[B]I have an old flange that is in concrete. The old closet bolts where broken off and set in the old flange not removable. I tried to drill new holes to set a new spacer ring but the cobalt bit just broke. Tried a twist and set flange but it was a 4" and the 3" one too big one too small. I am about to give up. What should I do to get a new flange in this pipe?

SEE POST #3 and #4 below...

I'm not a plumber so I wouldn't do it Mark's way, too much work. I'd do it the way I think you are attempting to do, by putting a metal ring over the old flange.

First Cobalt bits are for hardened steel, the flange is not hardened steel. Use a regular twits bit. Cobolt bits are very sharp but also very brittle and break easily. The screw holes for the ring should allow you to drill directly into the floor outside the flange. Use a hammer drill and a masonry percussion bit. Use lead anchors and stainless steel screws.

If you need or want to screw through the old flange drill out the flange with regular twist bit then switch to masonry bit to drill concrete. Drill hole through flange larger than you need, then drill hole in concrete for anchor.

Hi Harold...

My answer above, which I deleted here and posted to the right thread, was actually supposed to go to this thread:

https://www.askmehelpdesk.com/plumbing/what-best-way-raise-toilet-flange-4-25-a-479300.html

I am not sure how I posted this answer to this thread but somehow I did... UGH!

Anyway, HDRIDER... go with Harold's advice... dead on!

Mark

I did not use either one. I cleaned the area real good and used a pvc flange and gorilla glue. IT WORKS GREAT.