Whats the best way to cut out a Flue liner to install a pipe thimble.

[Seasoned Oak]

When installing a thimble into a terra cotta(think thats what they call it) flue liner i have not found a good way to cut a hole in the flue liner. WHen building new you can buy a liner section with a hole already in it.
So far iv been doing it with a hammer drill,but it busts up the liner too bad,instead of making a clean round hole. Even a ceramic tile rotozip bit wont cut these things, and i cant get a diamond blade saw in there so it would have to be some kind of rotary tool.

 

[ScotO]

When installing a thimble into a terra cotta(think thats what they call it) flue liner i have not found a good way to cut a hole in the flue liner. WHen building new you can buy a liner section with a hole already in it.
So far iv been doing it with a hammer drill,but it busts up the liner too bad,instead of making a clean round hole. Even a ceramic tile rotozip bit wont cut these things, and i cant get a diamond blade saw in there so it would have to be some kind of rotary tool.

Randy, Rotozip makes a diamond carbide 1/4" drive bit that does excellent in hard stone, in fact it is made to cut granite counter tops.....but it is quite pricey ($33.00 at my local Lowes)......well worth the money to get the job done right.....I bought one to cut a area of sandstone veneer (real stone, not the manmade stuff) and it works fine, but make sure you read the instructions there is a method that needs to be followed so you don't ruin the bit...after inserting the bit into the material you are cutting, you need to pump it in and out of the material so as to not ruin the diamonds on only one section of the bit....this will make the tool stay cool and last much longer for other projects in the future....again, you want the bit that was designed for GRANITE, not the ceramic bit........hope this helps out, good luck and keep us posted!....

 

[Seasoned Oak]

Thanks Scott i did not realize something like that was available. I cut the flue thimbles to size on an old table saw with a diamond edge 7.5 " blade in it. Works great where you have room ,but when working through a small hole in the chimney brick you need a small tool to get in there .The hammer drill busts up the liner too bad and then you have to patch it everywhere with Hi-temp cement,no the most ideal setup.
It would be worth $33 to do it right,and i am going to do some granite in the future anyway.

 

[pastera]

http://www.harborfreight.com/mercha...l-accessories/diamond-cutter-blade-67264.html
http://www.harborfreight.com/oscillating-multifunction-power-tool-68303.html

If you buy the multifunction tool, it will become a go-to favourite

 

[Seasoned Oak]

http://www.harborfreight.com/merchandising-promotions/merchandising/power-tool-accessories/oscillating-multifunction-tool-accessories/diamond-cutter-blade-67264.html
http://www.harborfreight.com/oscillating-multifunction-power-tool-68303.html

If you buy the multifunction tool, it will become a go-to favourite

WHat comes with the tool? Any accessories besides the sanding pad? Like the 3/4 angled cutter?

 

[karl]

http://www.harborfreight.com/merchandising-promotions/merchandising/power-tool-accessories/oscillating-multifunction-tool-accessories/diamond-cutter-blade-67264.html
http://www.harborfreight.com/oscillating-multifunction-power-tool-68303.html

If you buy the multifunction tool, it will become a go-to favourite

It's the first thing I have bought at Harbor Freight that had a power cord and wasn't a total piece of junk.