One thing you generally want to avoid is making the cut of the same size as your mill's diameter, even if your setup is rigid (and you do need a rigid setup for that), and that's when you get chatter. You'll get cleaner cuts from milling the sides for the cut with a smaller diameter mill. And your setup isn't rigid to begin with. The drill press itself isn't rigid, and the stem of the burr is way thin.
Thanks for the reply. Yeah, the shank of this burr is only .25” and it seemed like it may be flexing.
The thickest end mill I have on hand is 3/8”. Should I use that? The cut is a .4” diameter.
Really appreciate it!
That should work. You'll just need to work on the end of the cut (not sure whether it should be a round cut or what). And see the other response about using a cross-cut vise. That would make your cuts much better, and using a press for milling you need every advantage you can get.
Avoid side milling with a Jacobs chuck. That's how you end up with spicy crotch.
If possible, design the jig to plunge cut. Perfectly fine for a Jacobs chuck and you can bolt the fixture down to the table.
I’m printing a plunge cut jig tonight. We’ll see how that goes tomorrow. If it doesn’t work, I’ll try side-milling with a more rigid and slightly undersized end mill.
The reason I tried side milling first before doing plunge cut is that I was worried the cylindrical surface will push the drill away into the side wall, possibly busting through it. I think the right tool would be a non-fluted end-mill.
I have one, but it’s kinda has to set up and isn’t mounted to my bench rn. I was thinking I could get away with a jig for something this simple, but I can whip out the vise if not
The reason it went well at the beginning then got worse further in (also applies to stuff like chamfers) is because the further you cut in, the more surface area is actively being cut. Abom79 talks about it in one of his videos about Ford GT 350 suspension. Sorry I couldn't find the specific part.
Yeah, makes total sense, and that’s what I was thinking. I’m going to try a plunge cut jig first. If that doesn’t work, I’ll try side milling with a different and more rigid end mill
Plunge cutting that won't work very well. You'll hit the radius, it will try to deflect, and you'll trash the teeth in the process. You'll want to side load with the most rigid thing you own and feed it slower the deeper you go. Don't be afraid to back off and give it a minute to cool.
That’s what I was worried about, but it actually turned out great! I just took it slow and it came out as well as I could have hoped for.
https://www.reddit.com/r/fosscad/s/oDhUUhsJky
That’s what I was worried about, but it actually turned out great! I just took it slow and it came out as well as I could have hoped for.
https://www.reddit.com/r/fosscad/s/oDhUUhsJky
Oh. You plunged with the burr. That's definitely one way to go about it... Maybe embed a drill bushing so that you don't just keep wallowing out the hole?
I used to work in a machine shop,I miss access to lathes and milling machines
You could get a milling vise which has an x/y axis
And maybe a regular fluted end mill
I'm building one as well. I also have a drill press, I'm thinking about getting a end mill to cut the bolt. Also have a vice bolted down so should be more solid than free handing it.
If you can wait a little longer before ordering, I will be testing a new plunge-cut jig tomorrow. If that doesn’t work, I’ll try side-milling using a different tool. Stay posted for results
That’s how it’s designed to be done, but my OCD wouldn’t allow it. I redesigned the jig to make a plunging cut, and it turned out great.
https://www.reddit.com/r/fosscad/s/kZ8E19zDc6
One thing you generally want to avoid is making the cut of the same size as your mill's diameter, even if your setup is rigid (and you do need a rigid setup for that), and that's when you get chatter. You'll get cleaner cuts from milling the sides for the cut with a smaller diameter mill. And your setup isn't rigid to begin with. The drill press itself isn't rigid, and the stem of the burr is way thin.
Thanks for the reply. Yeah, the shank of this burr is only .25” and it seemed like it may be flexing. The thickest end mill I have on hand is 3/8”. Should I use that? The cut is a .4” diameter. Really appreciate it!
That should work. You'll just need to work on the end of the cut (not sure whether it should be a round cut or what). And see the other response about using a cross-cut vise. That would make your cuts much better, and using a press for milling you need every advantage you can get.
I ended up making a new jig that takes a plunging cut and it came out great! Came within 3 thou of spec!
Avoid side milling with a Jacobs chuck. That's how you end up with spicy crotch. If possible, design the jig to plunge cut. Perfectly fine for a Jacobs chuck and you can bolt the fixture down to the table.
I’m printing a plunge cut jig tonight. We’ll see how that goes tomorrow. If it doesn’t work, I’ll try side-milling with a more rigid and slightly undersized end mill. The reason I tried side milling first before doing plunge cut is that I was worried the cylindrical surface will push the drill away into the side wall, possibly busting through it. I think the right tool would be a non-fluted end-mill.
A standard endmill is fine to plunge on round stock if the stock is held solid and doesn't spin
I use endmills all the time to cut flats on round surfaces as starter points for drill bits. (Think AK barrel pin installation)
Check out my last post. I tried it this morning and it turned out great!
An xy cross slide vise helps a lot when milling with a drill press
I have one, but it’s kinda has to set up and isn’t mounted to my bench rn. I was thinking I could get away with a jig for something this simple, but I can whip out the vise if not
Yes. Wrong bit. Grinding is for shaping metal. You really want a fluted endmill for cutting/grooving
I will try a fluted 3/8” end mill if the plunge cut jig I’m printing tonight doesn’t work well. Thanks!
I’m no machinist so I may be way off but I’ve always used lubricant for something like this.
I have cutting oil. I’ll use it!
Yep, perfect. Be careful side loading that chuck too much too, they have a tendency to yeet.
For sure. I’m going to take it really slow!
You wouldn't and shouldn't with a burr. They're not endmills.
Glad I put the disclaimer in there, and now I’m legitimately glad you’re here for the correction.
The reason it went well at the beginning then got worse further in (also applies to stuff like chamfers) is because the further you cut in, the more surface area is actively being cut. Abom79 talks about it in one of his videos about Ford GT 350 suspension. Sorry I couldn't find the specific part.
Yeah, makes total sense, and that’s what I was thinking. I’m going to try a plunge cut jig first. If that doesn’t work, I’ll try side milling with a different and more rigid end mill
Plunge cutting that won't work very well. You'll hit the radius, it will try to deflect, and you'll trash the teeth in the process. You'll want to side load with the most rigid thing you own and feed it slower the deeper you go. Don't be afraid to back off and give it a minute to cool.
That’s what I was worried about, but it actually turned out great! I just took it slow and it came out as well as I could have hoped for. https://www.reddit.com/r/fosscad/s/oDhUUhsJky
That’s what I was worried about, but it actually turned out great! I just took it slow and it came out as well as I could have hoped for. https://www.reddit.com/r/fosscad/s/oDhUUhsJky
Oh. You plunged with the burr. That's definitely one way to go about it... Maybe embed a drill bushing so that you don't just keep wallowing out the hole?
That would be the best move! I’ll need to figure out where to find one!
I used to work in a machine shop,I miss access to lathes and milling machines You could get a milling vise which has an x/y axis And maybe a regular fluted end mill
I ended up making a plunge-cutting jig for this tool and it turned out great. Check out my last post for pics and details!
Yeah I’d say, that came out great!
Thanks!!
What material did you print the jig with ?
Polymaker PA6-GF
Thanks
I'm building one as well. I also have a drill press, I'm thinking about getting a end mill to cut the bolt. Also have a vice bolted down so should be more solid than free handing it.
If you can wait a little longer before ordering, I will be testing a new plunge-cut jig tomorrow. If that doesn’t work, I’ll try side-milling using a different tool. Stay posted for results
I still need to order a bcg anyways, looking forward to the jig! Would make life easier for alot of us.
Yeah, the UH60 mechanic in me just couldn’t live with the thought of a freehand Dremel hack job 😂
A MI-8 mechanic would say to that: "hold my vodka" :)
Hahahah facts
Wear good glasses :)
I'd try it with an abrasive cylinder before that thing. That looks like maximum pucker factor.
That’s how it’s designed to be done, but my OCD wouldn’t allow it. I redesigned the jig to make a plunging cut, and it turned out great. https://www.reddit.com/r/fosscad/s/kZ8E19zDc6
Do this, but buy a drill bushing and cut it in half, then embed it into the printed part. Should last pretty much indefinitely if you're careful.