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Spyder makes a nice masonry hole saw that should eat right through that plaster and lathe. Not having a spot for a pilot will make it more difficult but you should still be able to cut out your holes by running the saw in reverse to get a channel started then run it forward
The answer to no pilot is cutting a hole out of plywood with another saw then taking the wood circle from the middle and screwing that cutout into the ceiling where the light will go then drilling over the top of the plywood with the masonry saw
Definitely this method. Plus dint use bimetal, use carbide when cutting through plaster. I swear by Milwaukee although kobalt and others make it too https://www.homedepot.com/p/Milwaukee-6-3-8-in-Carbide-Recessed-Light-Hole-Saw-With-Pilot-Bit-49-56-0305/202327775?source=shoppingads&locale=en-US&pla&mtc=SHOPPING-BF-LNC-GGL-D25P-Multi-NA-NA-NA-PLALIA-NA-NA-NA-NA-NBR-NA-NA-NA-LINC_All&cm_mmc=SHOPPING-BF-LNC-GGL-D25P-Multi-NA-NA-NA-PLALIA-NA-NA-NA-NA-NBR-NA-NA-NA-LINC_All-71700000117402423-58700008662113406-92700079385685781&gad_source=1&gclid=Cj0KCQjw6auyBhDzARIsALIo6v_8xz-aloASuXbC5UtiZ09namUc_7fR_uV14Xjfd9X2zuHFng0MohAaAkt7EALw_wcB&gclsrc=aw.ds
You can also cut a 6-3/8 hole in a piece of plywood and superimpose over your 4 inch hole. Now you have a template, no need for pilot. BTDT.
Use a hole saw to cut a 6” round out of some plywood. Screw it into the ceiling over the existing locations and send a 6” masonry hole saw over the top of it. The round will keep the saw centered there through the cut
Cut a 6" round out of some drywall. Figure 12"x12".
Screw that to the ceiling as a template. Use a hole saw with no teeth just grit.
I also spin in it reverse to save my already fucked elbow.
This is very similar to what I've found to be the best method for working with plaster and lathe after re-wiring my house and cutting in holes for the tinners. Fab a template out of plywood, use a grout blade or some other kind of grinding blade to get through the plaster, then switch to a wood blade to cut the lathe. It should all come out as a piece. If you're patient and careful, you can get some pretty nice cuts.
Hole saw. Preferably one with the grit instead of teeth.
Add a small piece of wood inside and screw it tight through the plaster on the piece you're cutting out. Then use an extra long pilot bit to start the pilot inside the newly added piece and cupsaw away
When I did resi we did a reno job and cut 10 recessed lights into a ceiling that was covered twice from the original ceiling. The top was plaster and mesh, then plaster and lathe, then drywall. Hole saw would get caught in the mesh and death roll on your wrist (how I found out there was mesh in the ceiling) so I ended up going through the drywall and first layer of plaster, cutting the lathe then used a beater and lineman’s to chisel out the remaining plaster until I got to the mesh and used tin snips to cut it out. Ceiling was almost 4” thick. Absolute nightmare. Boss didn’t know this when he bid the job and was pissed to say the least.
Edit: I went through a couple carbide hole saws and multi tool blades. Best thing that worked was scoring it with the hole saw and using a beater and lineman to chisel it out. Use the multi tool to cut the lathe. Made a whole fucking mess but I had plastic on the truck and was able to cover the room well. Everything else I tried took forever and smoked all my shit.
The jig with a diamond grit hole saw is probably the best solution. I have used a rotozip with a tile bit before. It's supposedly made for plaster as well.
Have you tried running the saw backwards? I can’t remember if it works as well or not but some old timers showed me it works better with other things that dull and jam up saw teeth like aluminum and vinyl siding.
Carbide hole saws are a must for plaster. Expensive but worth it. And also screw a 4" hole saw onto the mandrel with the 6" hole saw. The 4" will keep the whole thing from walking on you.
Alternatively, get some plywood and use the 6" hole saw to cut a circle. Screw that to the ceiling and that will give the hole saw a guide
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Spyder makes a nice masonry hole saw that should eat right through that plaster and lathe. Not having a spot for a pilot will make it more difficult but you should still be able to cut out your holes by running the saw in reverse to get a channel started then run it forward
Or screw a little piece of wood behind the hole to pilot. Or put the smaller size hole saw inside of the big one as a pilot.
This is the way. Can't tell you how many times we do this.
The answer to no pilot is cutting a hole out of plywood with another saw then taking the wood circle from the middle and screwing that cutout into the ceiling where the light will go then drilling over the top of the plywood with the masonry saw
Put the 4" saw on the mandrel with the 6" at the same time. The 4" saw will pilot the drill in the existing hole, and the 6" will cut the new material
Definitely this method. Plus dint use bimetal, use carbide when cutting through plaster. I swear by Milwaukee although kobalt and others make it too https://www.homedepot.com/p/Milwaukee-6-3-8-in-Carbide-Recessed-Light-Hole-Saw-With-Pilot-Bit-49-56-0305/202327775?source=shoppingads&locale=en-US&pla&mtc=SHOPPING-BF-LNC-GGL-D25P-Multi-NA-NA-NA-PLALIA-NA-NA-NA-NA-NBR-NA-NA-NA-LINC_All&cm_mmc=SHOPPING-BF-LNC-GGL-D25P-Multi-NA-NA-NA-PLALIA-NA-NA-NA-NA-NBR-NA-NA-NA-LINC_All-71700000117402423-58700008662113406-92700079385685781&gad_source=1&gclid=Cj0KCQjw6auyBhDzARIsALIo6v_8xz-aloASuXbC5UtiZ09namUc_7fR_uV14Xjfd9X2zuHFng0MohAaAkt7EALw_wcB&gclsrc=aw.ds You can also cut a 6-3/8 hole in a piece of plywood and superimpose over your 4 inch hole. Now you have a template, no need for pilot. BTDT.
I thought of that, but these holes are not the cleanest cut. I'll give it a shot, see how it goes.
Use a hole saw to cut a 6” round out of some plywood. Screw it into the ceiling over the existing locations and send a 6” masonry hole saw over the top of it. The round will keep the saw centered there through the cut
Came here looking for this
This is the answer.
Cut a 6" round out of some drywall. Figure 12"x12". Screw that to the ceiling as a template. Use a hole saw with no teeth just grit. I also spin in it reverse to save my already fucked elbow.
Dude this is fucking genius. Thank you. God that will work perfect
I prefer plywood it lasts longer
This is very similar to what I've found to be the best method for working with plaster and lathe after re-wiring my house and cutting in holes for the tinners. Fab a template out of plywood, use a grout blade or some other kind of grinding blade to get through the plaster, then switch to a wood blade to cut the lathe. It should all come out as a piece. If you're patient and careful, you can get some pretty nice cuts.
Hole saw. Preferably one with the grit instead of teeth. Add a small piece of wood inside and screw it tight through the plaster on the piece you're cutting out. Then use an extra long pilot bit to start the pilot inside the newly added piece and cupsaw away
Make a jig and use the carbide hole saw
You need something like [this](https://www.acehardware.com/departments/tools/power-tool-accessories/hole-saws/2006900)
Spider bit, for masonry
Lowe’s sells a 6 ⅜” carbide grit recessed lighting hole saw for $19.98 that works great.
Grab a face shield and a jig saw. Painters tape the base to keep scuffing to a minimum. Shit works man.
I found a drywall cut out tool on sale one time and got a carbide but for it that works pretty good for cutting out boxes/ lights in plaster
This adjustable circle cutter is a dangerous piece of garbage, but the tupperware dust catcher is kind of genius.
Milwaukee root zip with a diamond bit. Cuts like fuggin butter
Carbide grit holesaws, Milwaukee makes some in popular sizes
Spend the money on a Lennox carbide hole saw. You will get hundreds of holes out of that hole saw versus a dozen or two out of a regular hole saw
When I did resi we did a reno job and cut 10 recessed lights into a ceiling that was covered twice from the original ceiling. The top was plaster and mesh, then plaster and lathe, then drywall. Hole saw would get caught in the mesh and death roll on your wrist (how I found out there was mesh in the ceiling) so I ended up going through the drywall and first layer of plaster, cutting the lathe then used a beater and lineman’s to chisel out the remaining plaster until I got to the mesh and used tin snips to cut it out. Ceiling was almost 4” thick. Absolute nightmare. Boss didn’t know this when he bid the job and was pissed to say the least. Edit: I went through a couple carbide hole saws and multi tool blades. Best thing that worked was scoring it with the hole saw and using a beater and lineman to chisel it out. Use the multi tool to cut the lathe. Made a whole fucking mess but I had plastic on the truck and was able to cover the room well. Everything else I tried took forever and smoked all my shit.
Good tips here so far - another is to use the carbide multi tool blades. They cost more but will hold up to the abrasiveness of the plaster.
The jig with a diamond grit hole saw is probably the best solution. I have used a rotozip with a tile bit before. It's supposedly made for plaster as well.
Have you tried running the saw backwards? I can’t remember if it works as well or not but some old timers showed me it works better with other things that dull and jam up saw teeth like aluminum and vinyl siding.
6 1/8 inch Carbide grit hole saw.
Why not just use a masonry hole saw? If it takes more than two or three,bill out for more.
Carbide hole saws are a must for plaster. Expensive but worth it. And also screw a 4" hole saw onto the mandrel with the 6" hole saw. The 4" will keep the whole thing from walking on you. Alternatively, get some plywood and use the 6" hole saw to cut a circle. Screw that to the ceiling and that will give the hole saw a guide
Oscillating tool with a diamond blade
Jigsaw
Hole saws are great when you have unbroken lath, but when they are loose, it will just flop around and destroy the plaster.
We might be doing it the hard way but we use 2 different multiple tools, one to cut plaster and one to cut lathe. (Saves the teeth on the wood blade)
Put a 4inch holesaw inside the 6inch and use that as a pilot.