New thimble install

Louis

New Member
Oct 21, 2018
64
Ocean County, NJ
Going to be replacing my thimble that goes into a mason chimney.. need to do so because the one that was made before i bought the house is very low making it so that the stove pipe coming off the stove collar is a very very short run into the thimble.

I will probably use Rockford Chimney Supply's Insulated Wall Thimble (round), my question is whats the best way to make the 6.25" hole cleanly through the brick AND the 3/4" clay liner. would a core drill work? im sure there is a concern on the liner cracking, but i assume a core drill would be best.

also, if anyone has had experience with that company's wall thimble let me know how it went install wise and how you like the product.

Thank you!
 

HomeinPA

Minister of Fire
Jan 4, 2018
510
Central PA
Going to be replacing my thimble that goes into a mason chimney.. need to do so because the one that was made before i bought the house is very low making it so that the stove pipe coming off the stove collar is a very very short run into the thimble.

I will probably use Rockford Chimney Supply's Insulated Wall Thimble (round), my question is whats the best way to make the 6.25" hole cleanly through the brick AND the 3/4" clay liner. would a core drill work? im sure there is a concern on the liner cracking, but i assume a core drill would be best.

also, if anyone has had experience with that company's wall thimble let me know how it went install wise and how you like the product.

Thank you!
My experience....No easy way to cut through the terracotta with out ending up cracking the damn thing or breaking something and ending up needing a liner to go with the new thimble. You can try drilling a hundred smaller diameter holes around the circle with a masonry bit and then using a demo hammer to chisel it out but like I said, something always happens and your hosed. Call me a pessimist.
 

HomeinPA

Minister of Fire
Jan 4, 2018
510
Central PA
Core bit. Zoop.

You may be able to rent the bit and an sds+ drill at home depot.
Never seen a 6.5" core bit for something like this. 4" but not bigger. I'm sure somebody has something but you're going to need a seriously big tool to drive that puppy. No puns please......

I didn't know HD would rent tools. Is that something new?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
The only core bits I have seen that big need to be run wet. If it is in an unfinished basement that may work ok if not using a wet drill wont work
 

WinterinWI

Member
Dec 6, 2018
150
Wisconsin
A few years back, we had a contractor running new utilities for the building expansion we put up. He was using a 6"+ core bit run dry to go through a thick concrete wall. My arm got sore thinking about what would happen if that thing decided to bite.

Edit: This was at work.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
A few years back, we had a contractor running new utilities for the building expansion we put up. He was using a 6"+ core bit run dry to go through a thick concrete wall. My arm got sore thinking about what would happen if that thing decided to bite.

Edit: This was at work.
It is worth looking into. I have used core bits lots of times and the ones I have never found one over 3 that was dry
 

WinterinWI

Member
Dec 6, 2018
150
Wisconsin
They got the holes done, but for all I know, they just used a wet bit run dry and burned up a bit. I didn't stick around, I could hear it loud enough on the other side of the plant. It took him quite a while.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
They got the holes done, but for all I know, they just used a wet bit run dry and burned up a bit. I didn't stick around, I could hear it loud enough on the other side of the plant. It took him quite a while.
I will have to look again I would get one if I could find one you can run dry
 

jetsam

Minister of Fire
Dec 12, 2015
4,536
Long Island, NY
youtu.be
They got the holes done, but for all I know, they just used a wet bit run dry and burned up a bit. I didn't stick around, I could hear it loud enough on the other side of the plant. It took him quite a while.
I don't think anyone makes dry core bits for solid concrete. The steel gets too hot and the diamonds fall off.

Some contractors would rather bill an extra $150-$500 for a new bit than deal with the mucky water (which actually isn't bad, you just put down a plastic dropcloth and set up a clay dam on top of it, or if you have a helper just stick a shopvac under the bit).

We always used Hilti bits when I was making big holes in stuff; those guys are pricey. The big ones go into the thousands of dollars, and can cost more than the drill.
 
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Louis

New Member
Oct 21, 2018
64
Ocean County, NJ
Thank you all for the replies.. I would just use a dry bit. I know HD rents and has for a long time now but not sure if they rent odd sizes such as a 6.25. might just have to grab one from ebay. My main concern was cracking the clay liner, ill take it easy and maybe when i get to the clay do some perimeter holes before running the core bit so if it does crack its less likely to crack else where and more likely to crack hole to hole (hopefully).
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
I just did one today. I simply used a grinder with a diamond wheel after trying to drill holes. They were just blowing out on the backside.

IMG_20190220_090707.jpg IMG_20190220_091456.jpg IMG_20190220_092805.jpg IMG_20190220_114655.jpg
 
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begreen

Mooderator
Staff member
Nov 18, 2005
80,791
South Puget Sound, WA
Good tip and illustration!
 

Louis

New Member
Oct 21, 2018
64
Ocean County, NJ
I just did one today. I simply used a grinder with a diamond wheel after trying to drill holes. They were just blowing out on the backside.

View attachment 241169 View attachment 241170 View attachment 241171 View attachment 241173

Thanks for the photos! very helpful to have a visual. The hole you made in the clay was exaclty 6" ?? And diamond bit grinder, ill have to keep that in mind. Did you perhaps use the one from Rockford Chimney? if not, which did you use??
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
Thanks for the photos! very helpful to have a visual. The hole you made in the clay was exaclty 6" ?? And diamond bit grinder, ill have to keep that in mind. Did you perhaps use the one from Rockford Chimney? if not, which did you use??
It was cut to match the 6" clay crock I stubbed through the chimney block. I use the olympia insulated thimble that I buy directly from them. I don't know what Rockford sells it may be theirs. It is by far the easiest one I have found to work with. I took a pic of the thimble partially installed but it didn't save correctly for some reason.
 
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Louis

New Member
Oct 21, 2018
64
Ocean County, NJ
It was cut to match the 6" clay crock I stubbed through the chimney block. I use the olympia insulated thimble that I buy directly from them. I don't know what Rockford sells it may be theirs. It is by far the easiest one I have found to work with. I took a pic of the thimble partially installed but it didn't save correctly for some reason.

https://www.rockfordchimneysupply.com/chimney-pipes/adapters-and-accessories/insulated-chimney-thimble-rigid-pipe-connection.php
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
What is the worst one you have worked with?
Safe t thimble was probably the most pita. It works fine but just isn't as easy to install.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,264
central pa
awesome, thanks. did you have to motar/cement the pipe inside the clay? or was it snug enough to not have to
No I attached the clay crock with refractory cement then buttered the back of the insulated thimble before screwing it fast. The stainless was a snug fit through the crock so there was no need to mortar that. Plus he will probably be getting a stainless liner in a few years so I wanted that sleeve to be removeable
 

Louis

New Member
Oct 21, 2018
64
Ocean County, NJ
No I attached the clay crock with refractory cement then buttered the back of the insulated thimble before screwing it fast. The stainless was a snug fit through the crock so there was no need to mortar that. Plus he will probably be getting a stainless liner in a few years so I wanted that sleeve to be removeable

Got it. Thank you very much for the knowledge.