Best tool for cutting plaster and lath

[Andrew Nemeth]

Hello all,

I need to cut 9 large holes in a plaster ceiling to accommodate recessed ceiling cans. What is the best tool and method for doing this easily. I have had to do this several times before and I have never found a way that works really well. I know this is not quite a furniture grade woodworking question but this bunch has some of the best experience of any of the forums I visit.

Thanks for your input,

Andrew

[Josiah Bartlett]

I haven't tried them, but Lenox makes a hole saw specifically for this purpose. Look for Master-Grit hole saws.

I've had good luck cutting holes out for electrical boxes in my lath and plaster house using a Harbor Freight Multi tool, but those were all square.

[Ray Schwalb]

I've used Morse grit edge hole saws to cut holes for can lights, as well as Greenlee ones. In my experience, by far the slickest method for cutting in plaster and lath. I had set up a bucket with a hole in the bottom to catch the debris as well.

[Jay Jeffery]

I worked on a large projects retrofitting an old building with power cords, networking cables and fire alarm systems. We used bimetal home saws, which worked really well. The plaster grinds the sharp points off the teeth almost immediately, but they continued to cut until the gullies between the teeth became too small. I'd imagine a hole saw designed to cut plaster would have worked better, but the warehouse stocked the bimetal variety.

If you only need a few holes, you might just want to get a bimetal hole saw realizing it will become worthless for anything else. You might also just go with a cheap HF hogh carbon steel hole saw set and see how they work. A set of them will cost less than half what 1 decent bimetal hole saw would run you.

[Peter Quinn]

I've done something similar using a rotozip with a tile bit installed. It makes a nice clean hole, not sure about wanting to hold the rotozip over my head working in a ceiling. I haven't had great luck on smaller holes in my old plaster lathe house. The hole saw gets through the plaster just fine but can seem to grab the lathe somewhat aggressively and can cause a bit of damage and key failure to the surrounding area, so proceed cautiously depending on the age and condition of your plaster..

[scott vroom]

Stay away from any type of reciprocating saw as the blade will grab the lathe and shake it to the point where large areas of plaster will break loose from the lathe. Never tried a round hole saw, but I imagine you'll have the same problem. I always plan on just knocking off any loose plaster and repairing with a cementious mortar mix, then top coat with DW joint compound (looks just like french plaster when painted :)).

[Josiah Bartlett]

If you have access from above the ceiling, drill from the back. Then you can cut the lath before the plaster and it is less likely to destroy the key.

[Lee Schierer]

Supposedly the New Fein MultiMaster FMM 250Q can cut most any delicate material without disturbing the entire thing. I'm not sure how it works on round holes.