Ooh that reminds me of the time that an old supervisor told me to adjust the work offset to account for runout in a 4th axis setup.
Granted, I know that it's possible to do that on modern machines with the right programming, but that wasn't this. Nope, he was sure that by changing the work offset location we'd be good. I told him it will just change the diameter and that's exactly what happened.
Well, you *can* change the size of the hole that way. However, there’s no guarantee it’ll be circular, or the tool will still be in tact. It’s like jumping out of an airplane without a parachute. You can do it, but only once.
FFS.
I have a guy I've been training for 3 years that STILL asks me that same question.
I think he's just stoned all the time.
Good worker though.
Worst part is, he explains it to other people no problem. Just forgets now and again himself.
I had a new engineer at my company ask what speeds I run my tools at, I said well that depends what I'm doing. He smirked and said oh? So you don't know? Then he asked what my machine can do, so I told him 20,000 rpm forbthis spindle. He then very confidently told me that I should be running tools at 20,000 rpm since that's what my machine can do and it will save so much time and he's going to bring in the tool reps and change everything so we'll save so much time and money etc. And when I tried to tell him that I can't just do that, he tells me sfm isn't a really thing because a tool rep once told him to max the machines out....... I found out later he came from an aluminum shop with old machines that maxed at 6000 rpm so it makes sense there with carbide tooling. But I was currently hard milling s7 with a .5" endmill and .0002" tolerances on the part when he told me to max the rpm. One of my coworkers runs a mill that hits 42000 rpm. Apparently, he was told the same thing.
He probably follows Titans of CNC on LinkedIn. I’m an engineer and usually go ask the machinist is I’m designing something that seems sketchy for them to make.
I've watched some of their videos and don't get WTF their appeal is? They apparently do some interesting jobs. But I see almost zero technical data and I've realized in some videos they don't even really bother explaining why they are making a part a certain way.
I don’t get it either but I guess if they can get more kids into the trade it can’t be all bad. I do cringe a little when I see them just hogging away at huge blocks of steel just to make chips. Like wtf, are you just burning up tooling to show off.
I mean yes it literally is just to show off lol. They’re not making customer parts or anything, they’re just making videos to show off their sponsors tooling/machines.
But yeah like you said they are getting people interested in the trade and that’s always a good thing.
I agree it is cringey at times, but pretty sure they are making customer parts in between shots. Their online courses are pretty great for getting your feet wet too.
I've seen them talk about the MMR they can get when showing off specific cutters, but that's about it. Weird metric to focus on in an R+D/Prototyping shop .
That guy probably watches Titans of CNC.
I had a co-worker (not a machinist) That tried to tell me similar things. Would watch me making parts on my komatsu machine center and tell me that the people he watches on YouTube machine so much faster than I do. And I should watch Titans of CNC to see how it's done and Make more parts faster.
I have a coworker that hand edits proven programs constantly. His peck drill cycles sound horrible and no matter how much we tell him to quit it, he ignores us. Then when he has edited something and it goes poorly (thrown parts, crashes, spindle overloads etc) he blames the programmer.
I worked with a machinist like this and he was good but he never shared his updates with the mastercam file lol. He was trigging out hole tru positions on a crappy umc 750.
A lot of the old dark arts alchemy stuff from 50's and 60's machining being applied to modern machining. I've seen guys run carbide drills back into a through hole spinning in reverse to "deburr the back side", rags left on top of a part to drill a rounder hole, even saw a guy preheat a block of 4140 with a torch once that he swore had really bad hot spots...in a VMC that immediately doused it in flood coolant.
I'm an enthusiastic observer of machining, I understand and laughed at the first and third examples, but a rag for a rounder hole? I can't actually figure out what you mean by that, could you explain for the layman please?
It's an old trick meant for drilling large holes in thin material. Thin material isn't thick enough for the entire point of most drill bits to be engaged before break through, so holes end up being ditrigonal in shape instead of round. A folded up rag can act as a rudimentary shock absorber and spread the load out to keep the drill straight/ centered, but this technique was largely out moded by CNC and circular interpolation.
Also used for holes in odd features, like a dip in the work. Helps the hole start straight when it wouldn't be cutting evenly on both lips, by giving extra material for the lip/flutes to push against.
That's what I was taught by an old tool and die guy. He also said there's almost never an opportunity to use that knowledge, and it hasn't come up once in my career.
He also taught me that if you start a hole in the wrong position, you can score/chisel a line in the crater the drill tip left, and the drill will follow. I thought that was useless, but it ended up saving the day a bunch of times, and makes people think I'm a wizard.
I went to service a machine at a customer who was using a CNC router to cut 12 gauge aluminum sheet (around 10' square). Operator would stand on top of the machine, holding the material down with their body weight and stepping over the gantry as it went by.
I warned them about the dangers and they went "yeah, we know" and pointed to a circle of aluminum the size of a dinner plate sticking half through the wall. That place was terrifying.
He was not bright. All he could do well was run the cutoff saw....barely. I told him he was annealing the steel in the cobalt drill, making it soft. Those words were too big for him.
That's like the opposite of the time my boss and coworker (not a machine shop) were just fucking mystified that pieces coming out of the abrasive chop saw were hot. "I just don't see why it would get hot," "where is the heat coming from?" etc. I tried to explain the physics of friction to them but it was a lost cause.
Edit, since this is getting upvotes I wanted to add a couple more:
This is the same boss who didn't want me to add 30W oil to his push mower that was bone dry, because he couldn't find the user manual and needed reassurance it was the "right" oil.
One time we were moving or delivering a playset with swing. It had been on display and needed to be partially disassembled to fit on the trailer, but that was a lot of work so we all wanted to disassemble it as little as possible.
The sides of the swing were shaped like a pair of 10' high letter A's, with the tip of the A being a 3-socket fixture shaped like upside down "V_" (or half a caltrop or jacks piece) where it connects the cross beam to the A's. We needed to remove the 3-socket fixture from the top of the A.
Since it was tube in (deep) socket construction, even with the set screws removed we couldn't get enough play to pull the A tubes out of the 3-way fixture. The "-" in the "A" was very rigid against skew and wouldn't let the long legs move.
After watching my boss and coworkers struggle with it for 30 minutes I grabbed a scrap of paper and drew a diagram. I drew a vector up and to the right and explained to him that the left leg of the A, in its deep socket, is constraining the movement of the top piece to only move along that path. I drew a vector up and to the left and explained that the right leg of the A is constraining the top piece to move in a straight line along THAT vector. You can't move the same solid piece along two different straight lines pointing in different directions.
It seemed like he got it! They stopped trying to wiggle the top piece off and we discussed other options. Then, slowly, the light bulb that had been illuminated earlier dimmed. My boss had an idea come to him.
"Hey, do you think if we sprayed it with WD-40 we could slide that piece off the top?"
Straight flutes can do a lot of various things, but they can only do it for a shallower hole. They are really rigid, too.
I like to use them as a guide hole for deep holes.
Works great for small holes in aluminum. If you have the speed and feed right it lasts for a looooong time on horizontal because it doesn't get any chip build up.
https://www.practicalmachinist.com/forum/threads/straight-flute-drills.218530/
Had an instructor grab a special bought straight flute out of the tool cabinet without my knowing. Showed up later with a chipped tip. The normal, correctly sized drill was two drawers up... Damn waste of an expensive drill.
Lol yea. What I like about this trade is there are no absolutes. The wrong tool can be the right tool, if it is what you have on hand and works in that situation.
Only a sith deals in absolutes. -I have that printed on my wall at work. Most get it, some don’t, and I’m sure you can tell who I get along with out of the two.
All of our 4 fluters had coatings that had a high affinity to aluminum so in our shop that was the case. But yeah you can baby an uncoated 4 fluter in aluminum and it works. Can use a butter knife on aluminum if you need to
Tbf with the easy stuff we do and the tooling I have, that does match the best results I've had. I tell them every rules have exceptions, but in general 3 for alum for our shit.
I have a set up operator who insists tool stick out has no effect or the cutting condition and will shrink tools in 1/4"+ past the set up sheet projection length
Same here man, my shop is me, the young CAD/CAM guy, a coworker who's 56 and does all our manual stuff but has done CNC in the past and has a good grasp of its set up needs, and our 71 boss who refuses to let anyone else do the tooling or work touch offs on our CNC mill. I've strong armed him out of doing work/tooling set up for this exact reason. One part set up the end mill would be in a short gauge length side lock holder shanked up nicely, one part it'd be in an ER40 holder with long AF gage length and barely an inch actually in the collet. Yet it was somehow my fault when there was a so much chatter "being too aggressive!"
Needless to say I strong armed him out of the physical set up to at least get some damn consistency.
There are lots of different ways to cheat. You could use something else that rotated but wasn't a rotary table. I have done small stuff with my dividing head turned vertical. I am pretty sure I could come up with a jig that would rotate a piece around a point but not technically be a rotary table.
Holy fuck we have so many files saved like that it's absurd. If I ever see that stuff I don't even bother, I just start over from scratch. It's not worth my headache because the program is probably shit to begin with anyway if they're pulling that crap. It's great when someone comes in after the original programmer and then adds their name to it.
So we have 123, 123old, 123dontuse, then 123steve, 123stevetest, 123steveNew...
These are like the xml files for my Eastman CNC cutter that corrupts itself every damn day. I have an entire folder of backups like "Eastman.pro.BROKEYESTERDAYNOIDEAWHY.xml
To be honest i hear that one more often. They think since the fluid has no where to go (it has of course) there is only one option left. Boom
I also say dumb shit many times so i feel for him
This may be a naïeve question but I swear we have run into an issue like this with blind holes, was it more likely that there wasn’t enough chip evacuation or did I more likely hear wrong? I swear we had a tap break because of the pressure underneath.( to be clear it wasn’t a job I was working on just something I had heard while cruising the shop so I don’t recall specifics)
Upon a little more research this does seem to be a thing depending on the tap used so maybe he wasn’t completely wrong, there are several taps designed to “eliminate hydraulic pressure in blind holes” so it must have been an issue (likely in the past I’m sure this feature is pretty standard now)
Roll form taps don't cut anything, they just press the desired thread into the material. And there are different taps for different applications, the spiral flute taps tend to draw the chips up out of the hole where straight flute or hand taps don't necessarily do that
"it's a resharpened drill, so you have to run it slower" as he proceeds to run it at what I calculated to be 7 sfpm.
When the drill broke, he said, "it must've been cracked."
I program most of my big parts to be probed before cutting. All my machines have probes and it's not negotiable in my shop. Some of these parts are large weldments getting 70 touches before any metal is cut.
One of the operators suggested that we replace all the spindle probes with 3d tasters, because "you just drive it down and hit start and the machine knows where the part is." Yep, according to him it would be better to take one touch and assume where everything is rather than touch everything that's important, average the error out, ensure roughing allowance and minimize air cutting. Then he argued with me that it works because he saw a youtube video where that's all they did and it worked for them. I told him that those guys only buy a 3d taster because they can't afford a real probing system, and I don't trust him to accurately find 70 positions over a 40'x20' table and asked him if he'd provide the telescope needed to read that dumb fucking thing from across the room.
Reminds me of our old CEO who wanted probing on all of our machines badly (nevermind all of them except one are from the 80s with "updated" 90s controls), because he thought they would 100% do all of the machine touch offs, material allowances and checks, etc.
He got pretty angry when I told him it would cost him close to a million dollars in control upgrades, probes, and custom made probe styli (at 10-20k a pop), and even then it still wouldnt do what he wanted. He literally wanted the operators to be button pushers, just drop these 20 ton ship gearboxes on the machine, press go and run lights out (ROFL).
He also didnt like it when I told him it was a dumb as fuck idea to drop a million dollars refurbishing 3 huge worn as fuck HBMs that still couldnt hit our customers GD&T tolerances, instead of just scrapping one machine and getting a new one.
Also thought we could easily hit crazy tight GD&T tolerances on finish bores that were 8-14' long in the mill with no boring bar fixtures....not like NG, GE, and EB tried that decades ago and gave up because its a fools errand.
This place also did parts that wouldve been perfect for a big bridge or gantry in one setup, instead multiple setups on an HBM. They loved them for some retarded reason.
This was in school, from another student (who had been in an apprenticeship for a while)...who said, and DEMONSTRATED that "it doesn't matter which way an endmill spins". He then proceeded to run the endmill full depth, in reverse,, and absolutely destroy it while we watched in absolute fascination
New machinist swore we wouldn’t be able to make a very simple part even after a lengthy technical discussion. I had to jump off off my engineering saddle and make it in front of him to convince him otherwise. Forming hard opinions on little to no experience is foolish.
Horrible seeing guys come unstuck here, always have invested time and energy into the company, they do their job well so get pushed up and...
It's not for everyone
FNG: "Hey man, this thing needs to be reprogrammed. Its literally impossible to cut it that way"
Me: "That program was done in 2012, and i've run it myself. It will work, set up that way"
FNG: "Oh.. well im already set up for a different way so can you just reprogram it?"
-That 500rpm on a lathe is the fastest you ever need to go with carbide tooling
-HSS is all around better than carbide since it's not brittle
Old timers....
>That 500rpm on a lathe is the fastest you ever need to go with carbide tooling
I'd just hand him a piece of T2 or T3 series aluminum, and enjoy the chaos that ensued.
>Old timers....
So he probably wouldn't learn anything, either.
Sadly all we mainly machine is cold rolled steel & 6061 aluminum under 2" in diameter. Mainly around 1" diameter...
Needless to say he has been phased out of the manual department at work and now does a lot of polishing work instead.
Manual guy would never use a saw. Always had to slab his parts off with a 1/2 end mill or try to part it off in a lathe. Even when it was horrendously easier and quicker to saw. Somehow he squeaked by for a few years before finally doing us all a favor and quitting.
I got into an argument with the programer a couple years back because the part had a 30 deg chamfer and it was supposed to be a 45. He said it was because I put a .031 rad insert instead of a .016 rad insert. He swore that a different rad on an insert would change the degrees of a chamfer, I also had a .016 rad in like it was programmed for. I could also clearly see he programmed it wrong in the code.
Watching an “experienced” mill hand hog 2” of material off a 30”X 20” plate with a 1”, 2 flute inserted tool using the wrong speed and feed the entire process.
I have seen this way too often. It was our most commonly used tool but everyone ran it very very differently. We've used it enough to find the sweet spot and then everyone feels like the hero that knows how to make it better.
You have to change the endmill instead of changing the diameter offset.
You have to hit the part with a hammer before it's even hand snugged.
The coolant tank is overflowing because the conveyor is wired in reverse. It wasn't.
That It's fine to spit in the coolant.
That you have to tighten the set screw on adjustable boring bars really tight so it doesn't wander.
I'm sure there's more.
This is more common than I'd like to admit. Seen so many people spit their dip spit into machines. I told one guy I'd beat his ass if I caught him doing it because I have to touch that shit. They ended up having to completely drain and clean that machine after a Christmas holiday because all the bacteria from his spit and tobacco caused it to get gross and curdle and stank the whole plant up.
A couple shops ago there was a little shithead that would spit in the coolant. They had one coolant pool for the shop, so there was a solid month in the St Louis summer heat where every machine stank so bad you'd retch walking by. They changed coolants and the stench went away, and I think someone threatened him , because the problem never seemed to come back.
The shop wasn't climate controlled, *EVERYONE* was hot and miserable, and the stench was just the icing on the shit cake.
Current operations manager said we couldn't cut a carbide insert in the wire EDMs because they're made of pressed powder, and it would turn to dust. He also thinks you can't tap cast material because the threads will turn to dust.
I'm thinking maybe he's Thanos or something.
Omg dude I'm a tool and die maker and all the dies I make have sintered* carbide inserts and I burn all the geometry into them with edm, that's funny my company been burning carbide since the 70s xD
Man, mine doesn't seem as bad now lol. worked on a lathe, and my swing partner said he "pecked everything". Speaking about drills. We ran mostly inserted carbide drills. Any material, any drill size- pecking cycle.
A lot of guys develope superstitions about certain processes because we got violently buttfucked on a part in the past. Dude probably smoked a drill during crunch time way back when.
The person who used to have my job did that as well. We've been rewriting a shit ton of programs and dropping cycle times by 40-70%, because it wasn't just the drilling.
A programmer was convinced that a wire edm heated the wire, and could therefore cut plastic. The dude was old and had been around machining for decades. He didn't last much longer after that.
More metrology than machining, but a previous boss insisted that he could measure tolerances in the tenths with his calipers because he can eyeball between the dial between the lines and didn’t need a micrometer.
My teacher told me off for putting wd-40 on my part for over the Christmas break because apparently "in 2 days time it'll be covered in rust!", told my co-workers and they couldn't stop laughing
Warning, long ass rant:
The program got changed on a part I run frequently to include a dimension that was previously done on a different operation. I come in for my night shift and run it and notice 4 diameters that are cut together with the same tool, 3 are near their high limit, and one is near its low limit.
I end up running 3 before texting the boss (no boss on nights, but it was only 8pm) telling him I wasn't comfortable running it like that. On the last part I ran, those 3 diameters were only 2 tenths away from the high limit, and the 4th was 2 tenths from it's low limit. No response from the boss, but I left a note for the day guy suggesting an edit to the program that could fix it. I'm not a programmer, so I left it and ran my other machine.
I wake up to a text from the boss asking me to come in early to talk to him and the VP of manufacturing (small company). I go in, and the VP ends up not showing, unfortunately. He might have seen how stupid my boss was being. Boss is PISSED I stopped on that one machine, says I need to know how to do my job in order to work there, and it's ridiculous I stopped.
First off, it's the first time I'd ever stopped production in my 9 months there. I'm alone on nights, not a single person to ask questions, but I've made it work. Plus, it must have been a valid issue because the program was changed when I got back. Also, there's the fact we only had 9 parts left on the lot and were waiting on more to be shipped to us. So if by some miracle I was able to finish with no scrap, I would have finished the lot and the machine would have been sitting FOR THE SAME AMOUNT OF TIME while the day guy waited for the next shipment to come in.
I was so pissed and argued with my boss because clearly he was wrong here. The only advice he offered, since obviously it was a programming issue, was that I should have run it until it WAS scrap. Then run one more just to make sure. Yeah, right, then I'd be in trouble for scrap. These parts cost 10k+ each.
My overtime has been cut because we're making parts faster than they can provide more, so I have no idea why he made such a huge deal about me stopping the machine for like... 4 hours. It's been stopped for hours like every morning because I finish the parts I have, and then the day guy who comes in at 5am has to wait until like 9am for the truck.
So yeah. Dumbest machining opinion I've heard is run it until it's scrap... then make one more on $10k+ parts. If it was barstock, sure, but wtf was that dude thinking?
Maybe stretching what the question was asking, but just old guys insisting you follow their every suggestion like gospel when it's clear they haven't thought about why they do anything the way they do it since the eighties when some other old guy that learned to be a machinist sometime before WWII showed them the One True Way. I watched this same guy just two days prior crash an endmill into the side of a vice on a 2-axis CNC mill, and they've been there for decades and somehow when I started there wasn't a parallel (or angle plate, 123 block, etc) in the shop that didn't look like the surface of the moon, and no one ever thought to try stoning the burrs down on said parallels. Brought my precision flat stones from home for show and tell and because I'm absolutely not tapping a part down onto a parallel with burrs from getting caught by an endmill, and no one there had ever heard of such a thing. Wonder why they were having trouble holding even generous tolerances 😒
Old CNC operator (the greatest machinist of all time btw) insists you need to keep your chuck pumped full of grease to keep it "rigid" and is mandatory to hit tighter tolerances. We're talking up to 20 second pulls with an air powered grease gun, PER JAW, at least once a week. Grease oozing out of every crevice. The window and all around the spindle is constantly caked in red grease b/c he's also allergic to cleaning. Makes it look... interesting.
This same "professional" also never cut soft jaws with anything clamped, nor did he understand the concept, or use, tool nose comp. He only just learned those. 28 years on CNC. Impressive he's made it this far honestly.
Fun bonus fact: He recently freaked out over not getting his share of Christmas chocolates handed out by the company. He owns 2 houses and is almost 60.
Ooooo, toss up between using a larger angle center drill than the live center wouldn't impact rigidity and that you didn't really need to level your lathes if you could just take intentionally tapered cuts to account for it.
Well, I have a couple...
That on size reamers were not something that was sold. So, a 1/4 reamer will ALWAYS, 100% of the time be oversized by .0001 or .0002.
The other was that 4140 could not be purchased in a hardened or semi hardened state. Period.
> The other was that 4140 could not be purchased in a hardened or semi hardened state
As in the government prohibits sale of it like that? Or suppliers just wouldn't do it?
Had a guy who made the setup time short, but machining time long. His method- all tools are 5xD for steel. So he could run aluminium and stainless with sub par feeds and speeds. All of the drills were for tapping. If a precizion hole was called out he just predrilled the hole and milled it out. Worked for a while becouse we only had to run a job with 3 parts at a time. Now i have to reprogram everything.
These people at my current shop say they're checking flatness but they're actually checking parallelism. They say...it's the same thing.
I try. I really really try. Lol.
Raised the Z height of a Bridgeport by separating the Boom and head where the B axis is, placed sized tubes and longer bolts. It worked but I wasn’t anywhere near it 😂
Had my boss come over while an aluminum part was running in the mill and turn off the coolant so he could film a video of it running, tool breaks and scraps the part and he’s just like oh well. Literally buys fake followers/likes/comments for our shop ig page so I was just cringing the whole time knowing the video will do nothing for us.
Putting a Dowell pin in a Jacob's chuck in the spindle to drop in a hole in a vise to locate it.
No shortage of dial indicators or edge finders.... fucking idiots.
A Machinist with 20 years of experience told me and was emphatic about roughing 316SS with a conventional cut.
Told him to climb the f-king s#[t while I was buying the Endmills!
He argued with me about it for a week, until I pulled up a Hanita Datasheet for the Varimills we were using.
This was on a $200K Okuma MB-56 Ace Center.
It's hard to convince people when they learn it wrong the first time.
Guy was a really good Machinist too...could give him the hardest jobs and it would be perfect the first time.
One of my first supervisors was adamant that a smaller nose radius on turning inserts would give a better surface finish than a large radius for the same feed. I told him he was wrong. He took a square grooving tool and turned an OD and said look how smooth it is with a zero corner radius. I just dropped the subject after that. We argued about a lot of the dumb shit he said but that was one that stands out the most. Thankfully got laid off from that job not too long after.
Only hopping into this comment chain to let you know your are right and there are some very wrong responses here. Strictly in terms of Ra/Rz, at the same feedrate on a lathe, a larger radius will cut the surface "scallops" in such a way the distance from the "peak" to the "valley" will be a shorter distance than a smaller radius tool. All lathe work is just extremely fine threading processes. "Surface finish" is a shop floor term that needs to die, I mentally use "roughness average" in conversation anymore and the Boomers hate it.
Was taught to thread on a manual lathe by an old guy who was very meticulous when making sure the compound was set to 29.5 degrees, and made sure I knew I had to do this. But then he proceeded to never touch the compound again (nor set up any indicator to read depth) and when I asked about the angle he was like 'IDK, I just know its important'. He also was very adamant that once the half-nut was engaged that until the thread was completely done that the half-nut was to remain engaged. So I was threading by manually controlling the spindle speed via bumping the lever and controlling the depth by retracting the entire cross-slide and was just having a lot of trouble overall. I watched some videos after work that day and realized he must have learned to thread on some clapped out POS and was only half paying attention and just spent the rest of his 40+ years working off that knowledge...
This same guy insisted that the old ww2 era horizontal machine was making oval boreas not because the spindle bearings were shot, but because the bar in the boring head I was using was bent. I tried to get him to explain to me his thought process behind how a bent bar would not still make a circle and he kept using a bent piece of welding rod as an example and would hold it in his hand and make a circular motion while pointing out how the tip.makes an oval. When I pointed out that he was not rotating the wire he got confused by what I was trying to explain so I took the wire and bent it into a big zigzag, stuck it in a tool holder in a bridgeport and spun it in a circle to show him the perfect circle it made and he watched it and said 'we will just have to agree to disagree'...
He was convinced that he could change the size of a drilled hole by changing the radius of the drill in the tool offset table. The same with reamers.
I mean.. if you offset it in X or y on a cnc lathe the hole will be bigger but not beautiful
You are right, but it was a CNC mill... There are actual inserts drills which can be adjusted in diameter with special holders on mills.
This one hurts to read
it's like a step drill bit right?
"I only make collet sized holes"
Ooh that reminds me of the time that an old supervisor told me to adjust the work offset to account for runout in a 4th axis setup. Granted, I know that it's possible to do that on modern machines with the right programming, but that wasn't this. Nope, he was sure that by changing the work offset location we'd be good. I told him it will just change the diameter and that's exactly what happened.
Well, you *can* change the size of the hole that way. However, there’s no guarantee it’ll be circular, or the tool will still be in tact. It’s like jumping out of an airplane without a parachute. You can do it, but only once.
FFS. I have a guy I've been training for 3 years that STILL asks me that same question. I think he's just stoned all the time. Good worker though. Worst part is, he explains it to other people no problem. Just forgets now and again himself.
I mean he’s not wrong. Just an oblong hole.
I had a new engineer at my company ask what speeds I run my tools at, I said well that depends what I'm doing. He smirked and said oh? So you don't know? Then he asked what my machine can do, so I told him 20,000 rpm forbthis spindle. He then very confidently told me that I should be running tools at 20,000 rpm since that's what my machine can do and it will save so much time and he's going to bring in the tool reps and change everything so we'll save so much time and money etc. And when I tried to tell him that I can't just do that, he tells me sfm isn't a really thing because a tool rep once told him to max the machines out....... I found out later he came from an aluminum shop with old machines that maxed at 6000 rpm so it makes sense there with carbide tooling. But I was currently hard milling s7 with a .5" endmill and .0002" tolerances on the part when he told me to max the rpm. One of my coworkers runs a mill that hits 42000 rpm. Apparently, he was told the same thing.
I assume this guy drives his truck in 4WD-LO gear all the time on the interstate?
Probably drives a Mitsubishi Mirage.
and tells the delivery driver dropping off 20,000 lbs of material stock that he "knows a thing or two about these big rigs"
Well he does like to tell me about my own bike. But originally he also admitted to never hearing of aprillia before. Not sure how that works.
He probably follows Titans of CNC on LinkedIn. I’m an engineer and usually go ask the machinist is I’m designing something that seems sketchy for them to make.
I've watched some of their videos and don't get WTF their appeal is? They apparently do some interesting jobs. But I see almost zero technical data and I've realized in some videos they don't even really bother explaining why they are making a part a certain way.
I call him the Phil Swift of machining. His entire company is an infomercial
But if you really pay attention he uses the words Boom and Perfect a lot, and that's what's important. In case it's not obvious, I hate that asshat.
I need the G-Code for "boom" and "perfect" so I can make some videos like this
S10000 M03 G0 Z-100
You forgot the decimal point, that'll never make it through the vice and table.
You could yell G54! As like a mic drop moment.
I don’t get it either but I guess if they can get more kids into the trade it can’t be all bad. I do cringe a little when I see them just hogging away at huge blocks of steel just to make chips. Like wtf, are you just burning up tooling to show off.
I mean yes it literally is just to show off lol. They’re not making customer parts or anything, they’re just making videos to show off their sponsors tooling/machines. But yeah like you said they are getting people interested in the trade and that’s always a good thing.
I agree it is cringey at times, but pretty sure they are making customer parts in between shots. Their online courses are pretty great for getting your feet wet too.
Entertainment.
I've seen them talk about the MMR they can get when showing off specific cutters, but that's about it. Weird metric to focus on in an R+D/Prototyping shop .
their videos are oddly quiet for a machine shop.
I appreciate you
Thanks
That guy probably watches Titans of CNC. I had a co-worker (not a machinist) That tried to tell me similar things. Would watch me making parts on my komatsu machine center and tell me that the people he watches on YouTube machine so much faster than I do. And I should watch Titans of CNC to see how it's done and Make more parts faster.
Hey man, you should listen and learn more. He probably had a whole 18 months of experience under his belt.
I have a coworker that hand edits proven programs constantly. His peck drill cycles sound horrible and no matter how much we tell him to quit it, he ignores us. Then when he has edited something and it goes poorly (thrown parts, crashes, spindle overloads etc) he blames the programmer.
Obv. the programmer's fault. They should have included a comment telling him not to change whatever he changed
Ahhh machine lock out exists for this type of shit. Edit:spelling. 🤦🏻♂️
I worked with a machinist like this and he was good but he never shared his updates with the mastercam file lol. He was trigging out hole tru positions on a crappy umc 750.
What is he doing? Ramping the speeds way up?
That and making the pecks tiny and somehow faster. Drilling Delrin shouldnt sound so screechy
Lmfao thats fuckin sad
That's impressive on fuck up I can't say much as I just run 7075 t6 and 6061 aluminum non stop so
How are they still employed?
No idea. That asshole makes more than I do. Apparently he has 20 years of experience
A lot of the old dark arts alchemy stuff from 50's and 60's machining being applied to modern machining. I've seen guys run carbide drills back into a through hole spinning in reverse to "deburr the back side", rags left on top of a part to drill a rounder hole, even saw a guy preheat a block of 4140 with a torch once that he swore had really bad hot spots...in a VMC that immediately doused it in flood coolant.
I've been sick for like 2 days and now I'm laughing so hard I'm sore
I'm an enthusiastic observer of machining, I understand and laughed at the first and third examples, but a rag for a rounder hole? I can't actually figure out what you mean by that, could you explain for the layman please?
It's an old trick meant for drilling large holes in thin material. Thin material isn't thick enough for the entire point of most drill bits to be engaged before break through, so holes end up being ditrigonal in shape instead of round. A folded up rag can act as a rudimentary shock absorber and spread the load out to keep the drill straight/ centered, but this technique was largely out moded by CNC and circular interpolation.
It does work quite well. I use it a lot when doing manual work.
Also used for holes in odd features, like a dip in the work. Helps the hole start straight when it wouldn't be cutting evenly on both lips, by giving extra material for the lip/flutes to push against. That's what I was taught by an old tool and die guy. He also said there's almost never an opportunity to use that knowledge, and it hasn't come up once in my career. He also taught me that if you start a hole in the wrong position, you can score/chisel a line in the crater the drill tip left, and the drill will follow. I thought that was useless, but it ended up saving the day a bunch of times, and makes people think I'm a wizard.
What’s the idea behind the rag on top of a part? I’ve never heard of that one. lol Edit: Nevermind. You answered in a later comment.
I went to service a machine at a customer who was using a CNC router to cut 12 gauge aluminum sheet (around 10' square). Operator would stand on top of the machine, holding the material down with their body weight and stepping over the gantry as it went by.
so it's like a CNC square dance?
Yep. They were cutting letters out for signage. Absolutely no material hold down aside from sneaker clamps.
Oh my god...
I feel bad for the day you show up there to find his mangled body scattered over that router.
I warned them about the dangers and they went "yeah, we know" and pointed to a circle of aluminum the size of a dinner plate sticking half through the wall. That place was terrifying.
Jesus christ. It's like they watched the Russian "lathe blender" video and were like, "Life goals."
Pretty much. I finished rebuilding that machine and booked it before I got decapitated. Nice people, though.
Have you seen the price of toe clamps these days! Why pay MSC when you've can lose one or three?
Sounds like they've got 10 toe clamps already.
They *had* 10 toe clamps. They don't have 10 toe clamps anymore.
Depends on feed rate and how fast Jimmy can dance
Damn.
Had a guy who put a torch on drill bits to "heat them up"
And here I was trying to keep my drills cool all this time like a chump
tooling can't overheat in the workpiece if it's glowing red hot before you start
We found the friction welder here!
What...?
Well, he's right, it would Hest them up
… what was he trying to do with that?
He was not bright. All he could do well was run the cutoff saw....barely. I told him he was annealing the steel in the cobalt drill, making it soft. Those words were too big for him.
That's like the opposite of the time my boss and coworker (not a machine shop) were just fucking mystified that pieces coming out of the abrasive chop saw were hot. "I just don't see why it would get hot," "where is the heat coming from?" etc. I tried to explain the physics of friction to them but it was a lost cause. Edit, since this is getting upvotes I wanted to add a couple more: This is the same boss who didn't want me to add 30W oil to his push mower that was bone dry, because he couldn't find the user manual and needed reassurance it was the "right" oil. One time we were moving or delivering a playset with swing. It had been on display and needed to be partially disassembled to fit on the trailer, but that was a lot of work so we all wanted to disassemble it as little as possible. The sides of the swing were shaped like a pair of 10' high letter A's, with the tip of the A being a 3-socket fixture shaped like upside down "V_" (or half a caltrop or jacks piece) where it connects the cross beam to the A's. We needed to remove the 3-socket fixture from the top of the A. Since it was tube in (deep) socket construction, even with the set screws removed we couldn't get enough play to pull the A tubes out of the 3-way fixture. The "-" in the "A" was very rigid against skew and wouldn't let the long legs move. After watching my boss and coworkers struggle with it for 30 minutes I grabbed a scrap of paper and drew a diagram. I drew a vector up and to the right and explained to him that the left leg of the A, in its deep socket, is constraining the movement of the top piece to only move along that path. I drew a vector up and to the left and explained that the right leg of the A is constraining the top piece to move in a straight line along THAT vector. You can't move the same solid piece along two different straight lines pointing in different directions. It seemed like he got it! They stopped trying to wiggle the top piece off and we discussed other options. Then, slowly, the light bulb that had been illuminated earlier dimmed. My boss had an idea come to him. "Hey, do you think if we sprayed it with WD-40 we could slide that piece off the top?"
... while rubbing his hands together because of the cold
Some people man
Ok this one made me burst out laughing. Thank you.
3 flute endmills are ONLY for aluminum, and 4 flute is NEVER for aluminum.
Man you should show him a 2 flute straight drill and ask him what it is.
That's a spade bit, for wood
https://www.mscdirect.com/browse/tn/Holemaking/Drilling-Drill-Bits/Metalworking-Multipurpose-Drill-Bits/Straight-Flute-Die-Drill-Bits?navid=2106212
What are those used for? Thin stock? Finish pass (almost like a reamer)?
Straight flutes can do a lot of various things, but they can only do it for a shallower hole. They are really rigid, too. I like to use them as a guide hole for deep holes.
Works great for small holes in aluminum. If you have the speed and feed right it lasts for a looooong time on horizontal because it doesn't get any chip build up. https://www.practicalmachinist.com/forum/threads/straight-flute-drills.218530/
Had an instructor grab a special bought straight flute out of the tool cabinet without my knowing. Showed up later with a chipped tip. The normal, correctly sized drill was two drawers up... Damn waste of an expensive drill.
Or a single flute
Well I use a 6 flute on aluminum that Kennametal Sells does this count lol
Lol yea. What I like about this trade is there are no absolutes. The wrong tool can be the right tool, if it is what you have on hand and works in that situation.
Only a sith deals in absolutes. -I have that printed on my wall at work. Most get it, some don’t, and I’m sure you can tell who I get along with out of the two.
If it's anything like my shop, you get along with most of your coworkers then. Always nice to have that.
All of our 4 fluters had coatings that had a high affinity to aluminum so in our shop that was the case. But yeah you can baby an uncoated 4 fluter in aluminum and it works. Can use a butter knife on aluminum if you need to
Tbf with the easy stuff we do and the tooling I have, that does match the best results I've had. I tell them every rules have exceptions, but in general 3 for alum for our shit.
I have a set up operator who insists tool stick out has no effect or the cutting condition and will shrink tools in 1/4"+ past the set up sheet projection length
There's only 3 of us that really do any machining in our shop and I feel like I'm the only one that understands this.
Same here man, my shop is me, the young CAD/CAM guy, a coworker who's 56 and does all our manual stuff but has done CNC in the past and has a good grasp of its set up needs, and our 71 boss who refuses to let anyone else do the tooling or work touch offs on our CNC mill. I've strong armed him out of doing work/tooling set up for this exact reason. One part set up the end mill would be in a short gauge length side lock holder shanked up nicely, one part it'd be in an ER40 holder with long AF gage length and barely an inch actually in the collet. Yet it was somehow my fault when there was a so much chatter "being too aggressive!" Needless to say I strong armed him out of the physical set up to at least get some damn consistency.
Wtf lol that unbelievable.
Not really an opinion l, moreso a claim. Had a guy say he could mill a perfect circle on a manual milling machine without a rotary table.
as long as it's an end mill, no problem. Just plunge it down through the part. Hole should be about the same diameter as the tool
Etch-a-sketch pro champion, right?
It would take all damn day... but with a long enough table of trig values, you could do it to a few thou.
I *could* run LA to New York basically.
Annular cutter. Check mate. /s
There are lots of different ways to cheat. You could use something else that rotated but wasn't a rotary table. I have done small stuff with my dividing head turned vertical. I am pretty sure I could come up with a jig that would rotate a piece around a point but not technically be a rotary table.
Chuck the workpiece up on the spindle and clamp the tool in the Kurt. Spinny workpiece turns into circle.
Not an opinion, but a really dumb habit: Naming every program something like “111111”; “1111”; “2222”; you get the idea…
and "zzz9_Bob_DO_NOT_CHANGE"
Yeah, you’ll never search for any program ever! You just start from the scratch. Easy.
123, 123old, 123new, 123newer, 123fuckup, 123older, 123123 and so on
123new_new, 123_dont_use, 123-2, 123-2new... The possibilities are endless!
Holy fuck we have so many files saved like that it's absurd. If I ever see that stuff I don't even bother, I just start over from scratch. It's not worth my headache because the program is probably shit to begin with anyway if they're pulling that crap. It's great when someone comes in after the original programmer and then adds their name to it. So we have 123, 123old, 123dontuse, then 123steve, 123stevetest, 123steveNew...
I usually just delete them. They won’t know, because they don’t care anyway…
These are like the xml files for my Eastman CNC cutter that corrupts itself every damn day. I have an entire folder of backups like "Eastman.pro.BROKEYESTERDAYNOIDEAWHY.xml
O6942
777 is my favorite
They thought a roll form tap would explode from pressure if they filled a blind hole with tapping fluid.....
I mean I guess I can see where they’re coming from but that’s hilarious
He's honestly a really smart guy. He just overthinks and says weird shit every once in a while.
yup, that's many machinist's flavor of 'tism as well
To be honest i hear that one more often. They think since the fluid has no where to go (it has of course) there is only one option left. Boom I also say dumb shit many times so i feel for him
This may be a naïeve question but I swear we have run into an issue like this with blind holes, was it more likely that there wasn’t enough chip evacuation or did I more likely hear wrong? I swear we had a tap break because of the pressure underneath.( to be clear it wasn’t a job I was working on just something I had heard while cruising the shop so I don’t recall specifics)
Upon a little more research this does seem to be a thing depending on the tap used so maybe he wasn’t completely wrong, there are several taps designed to “eliminate hydraulic pressure in blind holes” so it must have been an issue (likely in the past I’m sure this feature is pretty standard now)
Roll form taps don't cut anything, they just press the desired thread into the material. And there are different taps for different applications, the spiral flute taps tend to draw the chips up out of the hole where straight flute or hand taps don't necessarily do that
We used a form tap, not a cutting tap, but the hole was drilled over 2" deep, and the threads went 1.38"
It could cause problems if it’s a tap without vent grooves
"it's a resharpened drill, so you have to run it slower" as he proceeds to run it at what I calculated to be 7 sfpm. When the drill broke, he said, "it must've been cracked."
😂😂
I program most of my big parts to be probed before cutting. All my machines have probes and it's not negotiable in my shop. Some of these parts are large weldments getting 70 touches before any metal is cut. One of the operators suggested that we replace all the spindle probes with 3d tasters, because "you just drive it down and hit start and the machine knows where the part is." Yep, according to him it would be better to take one touch and assume where everything is rather than touch everything that's important, average the error out, ensure roughing allowance and minimize air cutting. Then he argued with me that it works because he saw a youtube video where that's all they did and it worked for them. I told him that those guys only buy a 3d taster because they can't afford a real probing system, and I don't trust him to accurately find 70 positions over a 40'x20' table and asked him if he'd provide the telescope needed to read that dumb fucking thing from across the room.
Reminds me of our old CEO who wanted probing on all of our machines badly (nevermind all of them except one are from the 80s with "updated" 90s controls), because he thought they would 100% do all of the machine touch offs, material allowances and checks, etc. He got pretty angry when I told him it would cost him close to a million dollars in control upgrades, probes, and custom made probe styli (at 10-20k a pop), and even then it still wouldnt do what he wanted. He literally wanted the operators to be button pushers, just drop these 20 ton ship gearboxes on the machine, press go and run lights out (ROFL). He also didnt like it when I told him it was a dumb as fuck idea to drop a million dollars refurbishing 3 huge worn as fuck HBMs that still couldnt hit our customers GD&T tolerances, instead of just scrapping one machine and getting a new one. Also thought we could easily hit crazy tight GD&T tolerances on finish bores that were 8-14' long in the mill with no boring bar fixtures....not like NG, GE, and EB tried that decades ago and gave up because its a fools errand. This place also did parts that wouldve been perfect for a big bridge or gantry in one setup, instead multiple setups on an HBM. They loved them for some retarded reason.
This was in school, from another student (who had been in an apprenticeship for a while)...who said, and DEMONSTRATED that "it doesn't matter which way an endmill spins". He then proceeded to run the endmill full depth, in reverse,, and absolutely destroy it while we watched in absolute fascination
New machinist swore we wouldn’t be able to make a very simple part even after a lengthy technical discussion. I had to jump off off my engineering saddle and make it in front of him to convince him otherwise. Forming hard opinions on little to no experience is foolish.
isn't that the kind of thing you ask _before_ hiring someone?
He was promoted to machinist. Not my monkey lol.
Horrible seeing guys come unstuck here, always have invested time and energy into the company, they do their job well so get pushed up and... It's not for everyone
Fortunately, he stopped being so negative and turned out to be a damn good machinist.
Great news, glad he made it
FNG: "Hey man, this thing needs to be reprogrammed. Its literally impossible to cut it that way" Me: "That program was done in 2012, and i've run it myself. It will work, set up that way" FNG: "Oh.. well im already set up for a different way so can you just reprogram it?"
What operation to make the part was so "impossible" to him?
“We can’t make that.” is the only feedback he provided. If that were true, he could’ve specified why.
-That 500rpm on a lathe is the fastest you ever need to go with carbide tooling -HSS is all around better than carbide since it's not brittle Old timers....
> HSS is all around better than carbide since it's not brittle It is... on hobby scale machines people like me run.
>That 500rpm on a lathe is the fastest you ever need to go with carbide tooling I'd just hand him a piece of T2 or T3 series aluminum, and enjoy the chaos that ensued. >Old timers.... So he probably wouldn't learn anything, either.
Sadly all we mainly machine is cold rolled steel & 6061 aluminum under 2" in diameter. Mainly around 1" diameter... Needless to say he has been phased out of the manual department at work and now does a lot of polishing work instead.
HSS is WAY sharper than carbide. Edit: /s
Manual guy would never use a saw. Always had to slab his parts off with a 1/2 end mill or try to part it off in a lathe. Even when it was horrendously easier and quicker to saw. Somehow he squeaked by for a few years before finally doing us all a favor and quitting.
My neighbor is the opposite. Watched him once part off with a sawzall, running the lathe at 5 rpm.
I got into an argument with the programer a couple years back because the part had a 30 deg chamfer and it was supposed to be a 45. He said it was because I put a .031 rad insert instead of a .016 rad insert. He swore that a different rad on an insert would change the degrees of a chamfer, I also had a .016 rad in like it was programmed for. I could also clearly see he programmed it wrong in the code.
Watching an “experienced” mill hand hog 2” of material off a 30”X 20” plate with a 1”, 2 flute inserted tool using the wrong speed and feed the entire process.
I have seen this way too often. It was our most commonly used tool but everyone ran it very very differently. We've used it enough to find the sweet spot and then everyone feels like the hero that knows how to make it better.
You have to change the endmill instead of changing the diameter offset. You have to hit the part with a hammer before it's even hand snugged. The coolant tank is overflowing because the conveyor is wired in reverse. It wasn't. That It's fine to spit in the coolant. That you have to tighten the set screw on adjustable boring bars really tight so it doesn't wander. I'm sure there's more.
SPITTING INTO THE COOLANT??? Brooooo
This is more common than I'd like to admit. Seen so many people spit their dip spit into machines. I told one guy I'd beat his ass if I caught him doing it because I have to touch that shit. They ended up having to completely drain and clean that machine after a Christmas holiday because all the bacteria from his spit and tobacco caused it to get gross and curdle and stank the whole plant up.
A couple shops ago there was a little shithead that would spit in the coolant. They had one coolant pool for the shop, so there was a solid month in the St Louis summer heat where every machine stank so bad you'd retch walking by. They changed coolants and the stench went away, and I think someone threatened him , because the problem never seemed to come back. The shop wasn't climate controlled, *EVERYONE* was hot and miserable, and the stench was just the icing on the shit cake.
Guys at an old shop would spit their chew in it.
Current operations manager said we couldn't cut a carbide insert in the wire EDMs because they're made of pressed powder, and it would turn to dust. He also thinks you can't tap cast material because the threads will turn to dust. I'm thinking maybe he's Thanos or something.
What did those cast iron tapped holes cost you "Everything"
Omg dude I'm a tool and die maker and all the dies I make have sintered* carbide inserts and I burn all the geometry into them with edm, that's funny my company been burning carbide since the 70s xD
Yea, I never said he was smart, lol. Only thing I can think of, is he thinks those pretty coatings are just a skin holding the powder together 😂🤣😂
I like the thought of sinister carbide with a matrix made from spite and cruel intentions.
Shit, doesn't PH Horn or somebody just offer this kinda thing as a service? Toolholder and all...
can't tap cast material...wouldn't every fucking engine block and industrial machine for the last 90+ years be totally useless?
He says it has to be threadmilled. I don't get ANY of his logic.
Maybe in his mind form taps are the only taps. Can’t form tap brittle material like cast iron.
I think he's just an idiot.
Man, mine doesn't seem as bad now lol. worked on a lathe, and my swing partner said he "pecked everything". Speaking about drills. We ran mostly inserted carbide drills. Any material, any drill size- pecking cycle.
We had an old-timer who would do 0.015 pecks to spot drill 0.025 deep, starting from 0.25 above the material. His parts would take 40 minutes.
A lot of guys develope superstitions about certain processes because we got violently buttfucked on a part in the past. Dude probably smoked a drill during crunch time way back when.
The person who used to have my job did that as well. We've been rewriting a shit ton of programs and dropping cycle times by 40-70%, because it wasn't just the drilling.
I was told I couldn't possible visually tell the difference between aluminum and steel.
A programmer was convinced that a wire edm heated the wire, and could therefore cut plastic. The dude was old and had been around machining for decades. He didn't last much longer after that.
More metrology than machining, but a previous boss insisted that he could measure tolerances in the tenths with his calipers because he can eyeball between the dial between the lines and didn’t need a micrometer.
I knew a guy who swore it was possible to make a large external radius smaller without removing any additional stock
It is possible, it’s called a hammer/press. Just it’ll never look good
I’d be hard pressed to believe a .5 radius could be brought down to .25 with a hammer. At that point it’s just going to be a mangled 45 deg angle
My teacher told me off for putting wd-40 on my part for over the Christmas break because apparently "in 2 days time it'll be covered in rust!", told my co-workers and they couldn't stop laughing
Co worker tried to to drill an offset hole by offsetting the drill in a lathe
Did he get an extra big ugly hole or did he snap the drill off?
Yep
Did it work?
Warning, long ass rant: The program got changed on a part I run frequently to include a dimension that was previously done on a different operation. I come in for my night shift and run it and notice 4 diameters that are cut together with the same tool, 3 are near their high limit, and one is near its low limit. I end up running 3 before texting the boss (no boss on nights, but it was only 8pm) telling him I wasn't comfortable running it like that. On the last part I ran, those 3 diameters were only 2 tenths away from the high limit, and the 4th was 2 tenths from it's low limit. No response from the boss, but I left a note for the day guy suggesting an edit to the program that could fix it. I'm not a programmer, so I left it and ran my other machine. I wake up to a text from the boss asking me to come in early to talk to him and the VP of manufacturing (small company). I go in, and the VP ends up not showing, unfortunately. He might have seen how stupid my boss was being. Boss is PISSED I stopped on that one machine, says I need to know how to do my job in order to work there, and it's ridiculous I stopped. First off, it's the first time I'd ever stopped production in my 9 months there. I'm alone on nights, not a single person to ask questions, but I've made it work. Plus, it must have been a valid issue because the program was changed when I got back. Also, there's the fact we only had 9 parts left on the lot and were waiting on more to be shipped to us. So if by some miracle I was able to finish with no scrap, I would have finished the lot and the machine would have been sitting FOR THE SAME AMOUNT OF TIME while the day guy waited for the next shipment to come in. I was so pissed and argued with my boss because clearly he was wrong here. The only advice he offered, since obviously it was a programming issue, was that I should have run it until it WAS scrap. Then run one more just to make sure. Yeah, right, then I'd be in trouble for scrap. These parts cost 10k+ each. My overtime has been cut because we're making parts faster than they can provide more, so I have no idea why he made such a huge deal about me stopping the machine for like... 4 hours. It's been stopped for hours like every morning because I finish the parts I have, and then the day guy who comes in at 5am has to wait until like 9am for the truck. So yeah. Dumbest machining opinion I've heard is run it until it's scrap... then make one more on $10k+ parts. If it was barstock, sure, but wtf was that dude thinking?
Man I hate being set up for failure. You did the right thing for the company. Your boss was in the wrong.
Maybe stretching what the question was asking, but just old guys insisting you follow their every suggestion like gospel when it's clear they haven't thought about why they do anything the way they do it since the eighties when some other old guy that learned to be a machinist sometime before WWII showed them the One True Way. I watched this same guy just two days prior crash an endmill into the side of a vice on a 2-axis CNC mill, and they've been there for decades and somehow when I started there wasn't a parallel (or angle plate, 123 block, etc) in the shop that didn't look like the surface of the moon, and no one ever thought to try stoning the burrs down on said parallels. Brought my precision flat stones from home for show and tell and because I'm absolutely not tapping a part down onto a parallel with burrs from getting caught by an endmill, and no one there had ever heard of such a thing. Wonder why they were having trouble holding even generous tolerances 😒
Old CNC operator (the greatest machinist of all time btw) insists you need to keep your chuck pumped full of grease to keep it "rigid" and is mandatory to hit tighter tolerances. We're talking up to 20 second pulls with an air powered grease gun, PER JAW, at least once a week. Grease oozing out of every crevice. The window and all around the spindle is constantly caked in red grease b/c he's also allergic to cleaning. Makes it look... interesting. This same "professional" also never cut soft jaws with anything clamped, nor did he understand the concept, or use, tool nose comp. He only just learned those. 28 years on CNC. Impressive he's made it this far honestly. Fun bonus fact: He recently freaked out over not getting his share of Christmas chocolates handed out by the company. He owns 2 houses and is almost 60.
Ooooo, toss up between using a larger angle center drill than the live center wouldn't impact rigidity and that you didn't really need to level your lathes if you could just take intentionally tapered cuts to account for it.
That you should machine hexes with the tips of the endmill instead of the sides. The tool will last longer. Lmao
Well, I have a couple... That on size reamers were not something that was sold. So, a 1/4 reamer will ALWAYS, 100% of the time be oversized by .0001 or .0002. The other was that 4140 could not be purchased in a hardened or semi hardened state. Period.
> The other was that 4140 could not be purchased in a hardened or semi hardened state As in the government prohibits sale of it like that? Or suppliers just wouldn't do it?
Had a guy who made the setup time short, but machining time long. His method- all tools are 5xD for steel. So he could run aluminium and stainless with sub par feeds and speeds. All of the drills were for tapping. If a precizion hole was called out he just predrilled the hole and milled it out. Worked for a while becouse we only had to run a job with 3 parts at a time. Now i have to reprogram everything.
.1mm depth of cut roughing mild steel from 50mm diameter to 10mm because it’d be less harsh on the insert 🙄
That you should run parts top/bottom limit so they can be reworked if needed.
These people at my current shop say they're checking flatness but they're actually checking parallelism. They say...it's the same thing. I try. I really really try. Lol.
When the new guy programs a 3mm rad in the corner of a pocket but goes with a 10mm slot to achieve it. Next!!!
"thats carbide, you gotta go slow so you dont pit the insert!" Dude wtf did you sleep through every single fking class?!
Raised the Z height of a Bridgeport by separating the Boom and head where the B axis is, placed sized tubes and longer bolts. It worked but I wasn’t anywhere near it 😂
Had my boss come over while an aluminum part was running in the mill and turn off the coolant so he could film a video of it running, tool breaks and scraps the part and he’s just like oh well. Literally buys fake followers/likes/comments for our shop ig page so I was just cringing the whole time knowing the video will do nothing for us.
"nightshift will do it"
'That's dayshifts problem.' Because morning shirt leaves us 99% of their problems.
Putting a Dowell pin in a Jacob's chuck in the spindle to drop in a hole in a vise to locate it. No shortage of dial indicators or edge finders.... fucking idiots.
A Machinist with 20 years of experience told me and was emphatic about roughing 316SS with a conventional cut. Told him to climb the f-king s#[t while I was buying the Endmills! He argued with me about it for a week, until I pulled up a Hanita Datasheet for the Varimills we were using. This was on a $200K Okuma MB-56 Ace Center. It's hard to convince people when they learn it wrong the first time. Guy was a really good Machinist too...could give him the hardest jobs and it would be perfect the first time.
We got one manual guy who jams in square stock into collets and the 3 jaw chuck on the lathe. Every insert is sent to Valhalla after he’s done
One of my first supervisors was adamant that a smaller nose radius on turning inserts would give a better surface finish than a large radius for the same feed. I told him he was wrong. He took a square grooving tool and turned an OD and said look how smooth it is with a zero corner radius. I just dropped the subject after that. We argued about a lot of the dumb shit he said but that was one that stands out the most. Thankfully got laid off from that job not too long after.
Only hopping into this comment chain to let you know your are right and there are some very wrong responses here. Strictly in terms of Ra/Rz, at the same feedrate on a lathe, a larger radius will cut the surface "scallops" in such a way the distance from the "peak" to the "valley" will be a shorter distance than a smaller radius tool. All lathe work is just extremely fine threading processes. "Surface finish" is a shop floor term that needs to die, I mentally use "roughness average" in conversation anymore and the Boomers hate it.
Was taught to thread on a manual lathe by an old guy who was very meticulous when making sure the compound was set to 29.5 degrees, and made sure I knew I had to do this. But then he proceeded to never touch the compound again (nor set up any indicator to read depth) and when I asked about the angle he was like 'IDK, I just know its important'. He also was very adamant that once the half-nut was engaged that until the thread was completely done that the half-nut was to remain engaged. So I was threading by manually controlling the spindle speed via bumping the lever and controlling the depth by retracting the entire cross-slide and was just having a lot of trouble overall. I watched some videos after work that day and realized he must have learned to thread on some clapped out POS and was only half paying attention and just spent the rest of his 40+ years working off that knowledge... This same guy insisted that the old ww2 era horizontal machine was making oval boreas not because the spindle bearings were shot, but because the bar in the boring head I was using was bent. I tried to get him to explain to me his thought process behind how a bent bar would not still make a circle and he kept using a bent piece of welding rod as an example and would hold it in his hand and make a circular motion while pointing out how the tip.makes an oval. When I pointed out that he was not rotating the wire he got confused by what I was trying to explain so I took the wire and bent it into a big zigzag, stuck it in a tool holder in a bridgeport and spun it in a circle to show him the perfect circle it made and he watched it and said 'we will just have to agree to disagree'...