T-nuts for chimney support attachment

[Sealcove]

I have Excel exterior pipe with a single bracket supporting the chimney from a roof edge. The stainless steel band that goes around the chimney pipe and the bracket is all in great shape, but the flat back T-nuts (that is the best term I can come up with for them) are corroding and failing. I probably have galvanic corrosion occurring with with three different metals, but these are 15+ years old so the issue is not severe . I did not dare take the intact ones off for a picture fearing they will break, but it is a flat disk against the chimney with a square stud at the base and then round threads on the outer section. The threaded portion is probably 1/4 in or 5/16. The image shows a broken one and a intact one with the square holes they mate with on the strap.

I stopped at my local stove shop and so far they don't have a source for just the T-nuts. I would have to buy a whole support kit, when I really just need three nuts (and I want to get spares for next time). Does anyone one know the correct name for these fasteners and a source for them? Thanks.

 

[bholler]

I have Excel exterior pipe with a single bracket supporting the chimney from a roof edge. The stainless steel band that goes around the chimney pipe and the bracket is all in great shape, but the flat back T-nuts (that is the best term I can come up with for them) are corroding and failing. I probably have galvanic corrosion occurring with with three different metals, but these are 15+ years old so the issue is not severe . I did not dare take the intact ones off for a picture fearing they will break, but it is a flat disk against the chimney with a square stud at the base and then round threads on the outer section. The threaded portion is probably 1/4 in or 5/16. The image shows a broken one and a intact one with the square holes they mate with on the strap.

I stopped at my local stove shop and so far they don't have a source for just the T-nuts. I would have to buy a whole support kit, when I really just need three nuts (and I want to get spares for next time). Does anyone one know the correct name for these fasteners and a source for them? Thanks.

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That is a ventis bracket not excell and those bolts should be stainless. I have never seen.that happen unless its used for coal. I would call the installer and get new ones

 

[Turbo89]

That’s definitely the result of an installing mistake, they should have been stainless (the intact joint looks like stainless washers / nuts, but carbon steel bolt).

I believe the style boat you’re looking for is a Plow Bolt. You might be able to just use a carriage bolt, if you can’t find them. The washers look like a large flat washer, split ring lock washer and regular hex nut (all in stainless), available at the local hardware store.

 

[Sealcove]

Thank and sorry the chimney is Excel, no recollection of the actual bracket. I was the installer more than 15 years ago. The stove shop I buy from is looking, but no leads on just the fasteners so far. Also, the fasteners were stainless"originally and I imagine a lower grade alloy and are serving as an anode in this corrosion quadrangle. I am near the coast, so plenty of fog and even salt air.

 

[Sealcove]

That’s definitely the result of an installing mistake, they should have been stainless (the intact joint looks like stainless washers / nuts, but carbon steel bolt).

I believe the style boat you’re looking for is a Plow Bolt. You might be able to just use a carriage bolt, if you can’t find them. The washers look like a large flat washer, split ring lock washer and regular hex nut (all in stainless), available at the local hardware store.

They were stainless and that is what was supplied with the bracket! That is what they look like after 15 years of galvanic corrosion. Again probably a low grade stainless alloy and the weak link in the chain here. The question is where to get good quality replacements? A SS carriage bolt could work, but it would likely dent the chimney a bit.

 

[Sealcove]

Looking at the galvanic series of conductive materials, the problem here is likely the galvanized steel strap coming from the roof. Though it being less noble I would have expected to find corrosion on it rather than a SS fastener (assuming 304 or better). Not knowing what the fasteners were actually made of makes this just a guess.

 

[Turbo89]

They were stainless and that is what was supplied with the bracket! That is what they look like after 15 years of galvanic corrosion. Again probably a low grade stainless alloy and the weak link in the chain here. The question is where to get good quality replacements? A SS carriage bolt could work, but it would likely dent the chimney a bit.

S.S. Carriage bolts will be at any good hardware store, Lowes, Home Depot, etc.

You’ll need to measure the existing holes /bolts to get size, but they came right up on Amazon as well (as elevator bolts):

https://a.co/d/06jrx4E

 

[Sealcove]

S.S. Carriage bolts will be at any good hardware store, Lowes, Home Depot, etc.

You’ll need to measure the existing holes /bolts to get size, but they came right up on Amazon as well (as elevator bolts):

https://a.co/d/06jrx4E

Ah that's the name I needed, elevator bolts. Knowing that I am finding 316 stainless options available at McMaster-Carr. I looked there quite a bit, but not knowing what to call them kept leading me in the wrong direction. Thanks a million! I will go double check the hole sizes (I have good access to it).

 

[bholler]

Thank and sorry the chimney is Excel, no recollection of the actual bracket. I was the installer more than 15 years ago. The stove shop I buy from is looking, but no leads on just the fasteners so far. Also, the fasteners were stainless"originally and I imagine a lower grade alloy and are serving as an anode in this corrosion quadrangle. I am near the coast, so plenty of fog and even salt air.

Ahhh that explains it. How many do you need? I can dig through my parts bin and see how many I have. I.domt use ventis anymore so i.dont need them

 

[bholler]

Ah that's the name I needed, elevator bolts. Knowing that I am finding 316 stainless options available at McMaster-Carr. I looked there quite a bit, but not knowing what to call them kept leading me in the wrong direction. Thanks a million! I will go double check the hole sizes (I have good access to it).

They are 1/4 20 bolts

 

[Sealcove]

Ahhh that explains it. How many do you need? I can dig through my parts bin and see how many I have. I.domt use ventis anymore so i.dont need them

Thanks, I just ordered a dozen from McMaster Carr. These are 316 SS and probably will not have this corrosion issue. I only need three, but I figured I would get extras while I was paying the shipping.

 

[Sealcove]

Greatly appreciate the help folks. It's a small item, but mission critical and winter winds are stating to kick in.

 

[begreen]

I would think that stainless truss head bolts of the appropriate size would work. They have a flatter head. Our ACE hardware store carries them.