Originally Posted by justboating
My drill bit 5 1/2 inch keeps wearing out and they are expensive . Any suggestions ?
When you say 5-1/2", I'm assuming that this is a hole saw? If so, I know what you mean as to the price. I had to cut 22-4" holes in my second floor ceiling which is also plaster and lath. My hole saw made it all the way through the job alas it was about as sharp as a bowl of oatmeal when I was done. After the fact, 220/221 indicated in an earlier thread (see below) that you could run the saw reverse through the plaster layer and then switch to forward to cut the wooden lath. Evidently, this would preserve the teeth since cutting the plaster layer is what's killing them.
I haven't tried it myself but go ahead and report back!
Also, look at entry #24, page two of the following thread (earlier on this site):
Hole saw advice for ceiling boxes
I devised a contraption to catch all of the plaster dust. PM me if you'd like a picture or more information. Also, a lot of discussion throughout about the subject of hole saws, etc.