Another broken screw thread (pun intended)

[NYSB]

I have a Regency CI2700 insert. I removed the catalyst flame guard for cleaning recently, which is held on by two bolts. The bolts thread directly into 1/4” steel plate. The head on the left hand bolt sheared right off, leaving the bolt shaft even with the plate. It is in a very hard to reach spot with about 4” of space between the bolt hole and the inside front of the stove. As far as I can tell there are no panels I can remove to get access - It’s all welded steel
plate. My right angle drills do not fit even with short bits. I was able to get a right angle attachment for my dremel tool and with a carbide bit have been able to drill into the bolt shaft. However, any other drill bit or left-handed extractor bit will not bite into the bolt - the material is just too tough.

With some patience I will be able to drill the bolt out of the hole with the dremel. I suspect the threads in the hole will no longer be intact.

Obviously one could normally just run a tap through the hole and be back in business. In this case there is not enough room to get a tap physically in there. Do they make a special tight-spaces tap?

Could i try a self-threading screw? Any specific type? Maybe a steel clip of some kind, like a retaining clip that with one end inserted into the hole and the other has a screw that tightens against the outside of the steel plate?

Any other suggestions?

 

[Max W]

Bummer, I’ll bet there is some hardened self tapping screw, maybe with a hex head. If not what about cutting your tap to size and grinding two opposing flat spots and using a mini vice grip. I haven’t used a dremel but there must be a blade capable of cutting that. Of course one would need to keep the tap from getting over heated.

 

[rwhite]

Do you have a welder? Is there enough meat left to tack a nut on top?

 

[NYSB]

No welder, no welding experience. Don’t know anyone with either. But i did come across that technique when doing some Google research on the problem. Tons of cool techniques out there. The primary problem here is where the screw is located It’s just so hard to reach and no room for the tools one would normally use for something like this.

 

[rwhite]

Not familiar with the stove or seeing the whole picture but what are the repercussions of leaving it broke?

 

[Frenchman]

I had a somewhat similar problem I think: https://www.hearth.com/talk/threads/bolt-problem-on-antique-wood-stove.187458/

You might get inspiration from the answers I had had.

Some things that could be done, given that you don't have access to the other side, and need to preserve the threading:

1. You could try to "carve" a cross to turn that bolt into a screw, then unscrew it.

2. You could use some special drill, that rotates backwards, and drill in the middle of the bolt. Once the drill gets a good grip inside the bolt, because it turns backwards, it will unscrew it.

Hope it helps!