Is this safe

[Eric Krewson]

I was drilling for my touch hole liner on a C weight barrel, the bit came loose out of my drill press chuck so I had to readjust. I didn't notice I was through the side of the barrel barrel and had gone about half way through the other side. I went ahead and drilled all the way through. I tapped the extra hole to 10/32 and plan to put a 10/32 lock bolt in to plug the hole, the barrel is1/4" thick at this point.

Is this safe or should I have the barrel cut off and have it rebreeched.

 

[rich pierce]

I figure if having a threaded breech and vent liner is safe, this is safe. Some patent breeched guns had clean out screws in this position.

 

[Eric Krewson]

Also a fine place for plenty of LocTite thread locker, looks like I need some of the red stuff.

 

[Eric Krewson]

I don't have to go 10/32, would course threads be better?

 

[EC121]

Chambers uses a 1/4x32 on his liners. If it was very dangerous, there wouldn't be any liners, nipples, drums, or clean-out screws. We would only be shooting matchlocks or straight-drilled flintlocks..

 

[SDSmlf]

Any of the LocTite products will work. The 263 (red) is labeled as high strength. Just make sure the set screw does not protrude into the bore. Could just leave it proud on the outside and file flush to the flat after the LocTite has cured.

 

[LawrenceA]

As long as there are at least 3 threads the plug should have strength.
You could soft solder the plug in but if you brown then there would be a ring.

 

[SDSmlf]

I don't have to go 10/32, would course threads be better?

I would use the finest thread you have.

 

[LawrenceA]

If it were me.
I would use the narrowest screw possible.
I would cut the screw such that it was flish on the inside.
Loctite it in a screw it in tight.
Then while the loctite was still liquid cut the head off and lightly hammer the screw shaft into the barrel to minimise the appearance of the gap between the plug and the barrel.
When the loctite set then dress the plug down.

 

[DOUBLEDEUCE 1]

What about putting something down the bore on the end of a steel rod ? You could place something solid against the side of the bore, then gently run your plug screw through the barrel wall until it touches the solid block inside. Measure what you have of the screw sticking out of the barrel. Maybe mark it with Dykem so you’ll know just how far to drive the screw. Maybe file the end of the screw to a small flat so no ‘point’ will protrude much into the bore of the barrel.
Or, make a go- no go type plug/ gauge to drop down the barrel on the end of a rod. Run the screw in, then drop the go-no go in. Slowly back the screw out until the gauge drops freely past it.

 

[Eric Krewson]

I have the breechplug out and used a tang bolt with a shoulder. I have cut the bolt to where there is only a tiny nib is sticking into the barrel. I will use a diamond bit in a Dremel to carefully grind this nib down to conform with the round barrel inside, I did this once before on a protruding liner on a thin 12 ga barrel. I slightly countersink the hole on the outside and peen the end of the bolt into the countersink after the Loctite sets then dress it down.

 

[Sidney Smith]

Thats what the stop on the drill press is for, to prevent the bit from going too far.

 

[longcruise]

What if you tap with a through tap without completing the threads. Then try the plug and tap further little bits at a time until the plug draws tight at just the point of raching the bore.

I have never done this and there may be many reasons to NOT do this. Just throwing it out for further discussion.

 

[Kap]

I wouln't worry about it. I would use a allen set screw, their grade 8 steel. Most machine screws are grade 2. They make locking set screws that have a spot of lock tight already incorporated in the screw. Would you not be putting a hole their if you were making a left hand flint lock.

 

[The Crisco Kid]

Put a touchhole liner in the off side, inlet a left handed lock, and make the rifle ambidextrous!

 

[jerrywh]

Many old English rifles had a cleanout hole in the opposite side of the touch hole. I would go with a 1/4" 28 thread. just put a screw slot in it.

 

[hanshi]

I see no reason why it wouldn't be perfectly safe. If the vent liner won't blow out then neither will a good set-screw fix.

 

[Col. Batguano]

Yup. Just like the vent liner inside the bore, get it filed flush so patches don't hang up on it. Use a metal for the plug that will take the browning (or what ever finish you're planning on using) and it will be almost invisible. It should be pretty well covered by the wood on that side too.

 

[Zonie]

I was drilling for my touch hole liner on a C weight barrel, the bit came loose out of my drill press chuck so I had to readjust. I didn't notice I was through the side of the barrel barrel and had gone about half way through the other side. I went ahead and drilled all the way through. I tapped the extra hole to 10/32 and plan to put a 10/32 lock bolt in to plug the hole, the barrel is1/4" thick at this point.

Is this safe or should I have the barrel cut off and have it rebreeched.

The others have covered this quite well but I'll put in my two cents worth.

The #10-32 screw you plan on using to plug the hole can produce a force of 815 pounds without overstressing it.
At a breech pressure of 20,000 psi, the force of the gas pressure on the screw is 25.6 pounds.
That gives the screw a safety factor of over 31. More than enough for the job you are giving it.

 

[LawrenceA]

The others have covered this quite well but I'll put in my two cents worth.

The #10-32 screw you plan on using to plug the hole can produce a force of 815 pounds without overstressing it.
At a breech pressure of 20,000 psi, the force of the gas pressure on the screw is 25.6 pounds.
That gives the screw a safety factor of over 31. More than enough for the job you are giving it.

Now that certainly brings it into perspective.