Helicoil repair

[Jetmech]

Hello all, my 25 caliber 3/4” percussion barrel has worn drum threads. Is it acceptable to drill and helicoil before fitting a new drum? It appears that the helicoil O.D. will be wider than the barrel flat.

 

[brushblind]

I'm no expert but that sounds like a bad solution to me.

 

[poker]

Hello all, my 25 caliber 3/4” percussion barrel has worn drum threads. Is it acceptable to drill and helicoil before fitting a new drum? It appears that the helicoil O.D. will be wider than the barrel flat.

Could you just go to the next size thread? Even if you had to use metric.

 

[IanH]

Fit a fresh one, JB-Weld it in, and don't ever take it out. I don't take out my flintlock FH liners to clean them, and the threads never get ruined. If it gets hammered loose or egged from the hammer hitting it, work the sear nose to reduce the hammer fall distance and epoxy the drum back in.

 

[Scota@4570]

Is it acceptable to drill and helicoil before fitting a new drum?

.........No

 

[2 shots]

not safely , dont feel its safe to use a helicoil on guns, same with glueing in a piece that can come out like a bullet.

 

[waarp8nt]

I read online that heli-coil repairs can hold up to 200,000 psi, whch well beyond the pressure blackpowder produces, but I wouldn't trust it. Go the next size up with the drum or better yet cut off that section of barrel, re-install the breech plug, drill / Tap and install the drum like it was a new one.

 

[Greg Y]

A timesert would be 1000x better than a helicoil....but neither is right.

The next size drum would be the answer. You have to drill and tap an insert.....so just pony up a few extra bucks for a drum and save the insert price. In the end it's likely cheaper and certainly safer.

 

[SDSmlf]

Hello all, my 25 caliber 3/4” percussion barrel has worn drum threads. Is it acceptable to drill and helicoil before fitting a new drum? It appears that the helicoil O.D. will be wider than the barrel flat.

Personal decision whether or not to use a Helicoil or not. For what it is worth, there was quite the stink 15 to 20 years ago when Green Mountain used Helicoils to make a repair after the incorrect thread was drilled and tapped into a number of breech plugs. Heilicoils were not acceptable as a good idea at the time and likely not a good idea today. Drill and tap the barrel for a larger size threaded drum and do it right, at least in my opinion.

 

[Colonial Boy]

How did the threads become worn?

 

[French Colonial]

I Have not had very good luck with helicoil's on a Jasper rebuild engine, the head bolts kept stripping out well below the recommended torque settings. Personally, I would fill the hole by welding or brazing a bolt in the hole and redrill and tap.

 

[Old Hawkeye]

This thread is why I have this rule. NEVER stand on the side of a muzzleloader with a drum. They should be banned from any public range, because you never know what some "shade tree mechanic" has done to it.

 

[Whitworth]

I once saw a drum go into orbit due to a sloppy screw. Glad I wasn't standing beside Butch when he touched it off. YMMV

 

[Greg Y]

I've done a lot of helicoil repairs as a machinist and know they can be very stout if installed properly. My issue is that you'll be on a blind hole so you could drive the coil into the bore and not know it....and the drum is the very worst place for moisture to migrate and a helicoil is terrible for wicking.

That's the two main reasons a timesert is a better thread repair solution.

With that said, up sizing and re tapping takes all of the potential disaster away.

 

[Eric Krewson]

One of my friends had it in his head that he had to take the drum out every time he cleaned his rifle, over time the threads wallowed out and the drum got loose. Our mutual friend built the rifle so he took it back to him for a repair which amounted to having the rifle fitted with an oversized drum, problem solved, or so we thought. The builder cautioned his friend about removing the drum for cleaning but old habits die hard, within a year the drum was loose again. My friend fixed it again but said no more, he wouldn't fix the rifle again.

Sadly, cancer took the rifle's original owner a year or so later.

 

[Rebel bull]

I Have not had very good luck with helicoil's on a Jasper rebuild engine, the head bolts kept stripping out well below the recommended torque settings. Personally, I would fill the hole by welding or brazing a bolt in the hole and redrill and tap.

I have been doing these repairs for 20 plus years the repair is always tig or gas weld the hole at least 2 sizes smaller then surface it. set it up in the mill bore it and tap it to original spec's install the new drum, torque into place then drill and tap for the nipple or touch hole liner. I do this quite frequently.

 

[2 shots]

helicoils are coiled wire, seems a lot of fowling could work its way in and cause issues. just a thought. not an area that should be 'rigged'

 

[Jetmech]

I have been doing these repairs for 20 plus years the repair is always tig or gas weld the hole at least 2 sizes smaller then surface it. set it up in the mill bore it and tap it to original spec's install the new drum, torque into place then drill and tap for the nipple or touch hole liner. I do this quite frequently.

Thanks all,

I acquired this rifle with the drum slightly loose. I’ll measure diameter and TPI and install next size drum if possible. If already oversized I’ll look into a weld repair. Should be ready for squirrel season soon.

This rifle is a valued part of my meager collection, I will do the right thing to preserve its value and ensure safety of shooter and by-standers. No helicoil!

Thanks all for the advice and responses. A lot of experience on this forum and I appreciate it.

 

[LME]

Hello all, my 25 caliber 3/4” percussion barrel has worn drum threads. Is it acceptable to drill and helicoil before fitting a new drum? It appears that the helicoil O.D. will be wider than the barrel flat.

How did the threads become worn?

I was asking myself the same question? I wonder if it is just cross threaded? If so he could use a tap and die set and chase the threads?

 

[SPQR70AD]

This thread is why I have this rule. NEVER stand on the side of a muzzleloader with a drum. They should be banned from any public range, because you never know what some "shade tree mechanic" has done to it.

also never drive on a single lane road with a tractor trailer coming the other way