Touch hole behind Nipple too large?

Not that it's related to muzzleloading but the jet engine company I worked for forbid the use of Heli-coil inserts in our designs. The few times I used one on a part I was designing, I had to give a lot of reasons for using it and the head of Engineering had to bless it before my design could be approved.

The problem was first, these were self locking Heli-coils (which you would never want to use on a muzzleloader) and they tended to unscrew out of the part when a mechanic was trying to remove a screw that had been screwed into it. Because of this, we always used key or ring locked screw thread inserts in our designs.

Because of this tendency for the Heli-coil insert, and to help seal the threads to minimize powder gas from blowing thru the threads, if someone is going to use one of these inserts to repair a damaged nipple hole in their muzzleloader, I highly recommend using a thread locking compound or a epoxy to keep the insert in place.

AntiqueSledMan said:

What we used to do if clearance was an issue, take the next size smaller, drill & tap to what you want. Then you have a smaller insert with your threads in it. Sometimes we just used a bolt & put desired threads in it.

AntiqueSledMan.

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Yeah this sounds interesting someone else mentioned it earlier just put a bolt in and cut off the head and retap into it. Seems it would be way safer/stronger.

Epoxy that was mentioned could also be wise i guess.

I'm just going to fire this gun a few times, first 2-3 shots with a string, maybe 1-2 live rounds. Then it's pretty much going to hang on my wall, after i've fixed it up a little more

Now i'll have to touch the nipple after each stringshot and see if i see any signs of it loosening up i guess.

I'll make sure to keep my head clear of the nipple trajectory on the few live rounds, worst case scenario you'll read a newspaper story guy dead from percussion nipple haha.

Man, maybe this thread insert isn't such a good idea after all, i'll have to consider actually welding the hole and retapping it : P

"just put a bolt in and cut off the head and retap into it."

Putting a bolt with good threads into a hole with damaged threads would be no safer or stronger than putting a nipple with good threads into a bolster with damaged threads. The damaged female threads are the weak point and the bolt wouldn't change that no matter how good the threads on the bolt or nipple are.

hawkeye2 said:

"just put a bolt in and cut off the head and retap into it."

Putting a bolt with good threads into a hole with damaged threads would be no safer or stronger than putting a nipple with good threads into a bolster with damaged threads. The damaged female threads are the weak point and the bolt wouldn't change that no matter how good the threads on the bolt or nipple are.

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That's cute. Thank you sir! :- )

Larsen,

You would have to make the hole oversized, if it's a 5/16" thread required you'd probably want a m10x1.25 tapped hole (drill 31/64) and not drilled through but just as deep as the nipple threads are. You would need a standard and bottoming tap to finish the threaded hole. This way you don't block your ignition passage, and can bottom out your insert or bolt (what ever you decide to use). Then you could mill it flush with the top of the bolster and put your nipple threads into the insert material and your done. But like I said earlier, you would need to set this up in a mill to hold alignment.

That's how I'd do it, AntiqueSledMan.

AntiqueSledMan said:

Larsen,

You would have to make the hole oversized, if it's a 5/16" thread required you'd probably want a m10x1.25 tapped hole (drill 31/64) and not drilled through but just as deep as the nipple threads are. You would need a standard and bottoming tap to finish the threaded hole. This way you don't block your ignition passage, and can bottom out your insert or bolt (what ever you decide to use). Then you could mill it flush with the top of the bolster and put your nipple threads into the insert material and your done. But like I said earlier, you would need to set this up in a mill to hold alignment.

That's how I'd do it, AntiqueSledMan.

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Thank you, really helpful advice i'll do like you say.

It might be more common to have a metric nipple put in standard and the other way too then we think. I have friends that don't know the difference. I try to keep a supply of both on hand in case someone needs a change. They are a mess since I keep them in a little plastic container with anti seize. Most important thing you can do with clean out screws, nipples and spark plugs.
The worst is a rusted in nipple and many threads have been stripped out.
I like Okie's suggestion because I hate Heli Coils too. They have worked for spark plugs in the past. A nipple like a spark plug should be started by hand--NO wrench. I actually use a rubber hose on deep spark plugs to start.

45man said:

It might be more common to have a metric nipple put in standard and the other way too then we think. I have friends that don't know the difference. I try to keep a supply of both on hand in case someone needs a change. They are a mess since I keep them in a little plastic container with anti seize. Most important thing you can do with clean out screws, nipples and spark plugs.
The worst is a rusted in nipple and many threads have been stripped out.
I like Okie's suggestion because I hate Heli Coils too. They have worked for spark plugs in the past. A nipple like a spark plug should be started by hand--NO wrench. I actually use a rubber hose on deep spark plugs to start.

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Hey thanks for your advice.

I've decided to go with the helicoil for now and i'm also going to use some epoxy like someone suggested.

But since i've never fit a helicoil before i'll place a 2nd nipple in another piece of scrapmetal and overscrew it to rip out the threads/helicoil in my "test metal piece" before i decide to fire the rifle.

Just to get a feel of the actual strength of a helicoil, on that assesment ill decide if it's solid enough or not.

If i do think it's solid enough, i'm going to fire it 2 times with a string, then make an assesment of the nipple and if im pleased ill do 1 regular shot and then i'm going to retire this rifle on my wall.

If i was going to shoot this rifle thousands of times then i would def not go with a helicoil, but i think it will hold for this.

But i don't know i have no experience with these helicoils so maybe theyre really weak I've seen others doing this kind of thing and it seems to have worked for them at least, i think i should be fine.

I used a helicoil in a Morrocan style Afghany bazaar gun I picked up in an estate buyout.
The gun is a hand hammered homemade with a rolled/welded tube for a barrel and a plug welded onto that for a breech.
The musket nipple was stripped.
I did shoot it several times after repair with some very light loads and a smallish ball (.575 in a .65 barrel) but the helicoil held fast and worked. Yes the gun is dangerous, but has a very long documented history, including taking out the pilot in a Russian helicopter during the Russian invasion. Long story and documented in another thread on this forum.
Don't be afraid of the helicoils, just install carefully and be mindful that it is a makeshift repair.

Griz44Mag said:

I used a helicoil in a Morrocan style Afghany bazaar gun I picked up in an estate buyout.
The gun is a hand hammered homemade with a rolled/welded tube for a barrel and a plug welded onto that for a breech.
The musket nipple was stripped.
I did shoot it several times after repair with some very light loads and a smallish ball (.575 in a .65 barrel) but the helicoil held fast and worked. Yes the gun is dangerous, but has a very long documented history, including taking out the pilot in a Russian helicopter during the Russian invasion. Long story and documented in another thread on this forum.
Don't be afraid of the helicoils, just install carefully and be mindful that it is a makeshift repair.

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That's comforting to hear for sure thank you for that, i'll make sure to update anyone interested about my progress in the future, and thanks to each and everyone who replied and helped me out, you guys are the best.

Morrocan style Afghany Bazaar ? . I wont say never the twain would meet, but I think it most unlikely . Have you a picture not of the botched lock but of the whole piece The forged breech suggests its More Indo Persian region not Morrocan .While many regard all such as wall hanger décor it wasn't made to be and I rather like them . I've known them in use in Central Algeria that was in the 60s ( maybe the've got SKSs now). I gave one old owner two flints I was carrying & he beamed like a Cheshire cat .great people I found . Rudyard

Rudyard said:

Morrocan style Afghany Bazaar ? . I wont say never the twain would meet, but I think it most unlikely . Have you a picture not of the botched lock but of the whole piece The forged breech suggests its More Indo Persian region not Morrocan .While many regard all such as wall hanger décor it wasn't made to be and I rather like them . I've known them in use in Central Algeria that was in the 60s ( maybe the've got SKSs now). I gave one old owner two flints I was carrying & he beamed like a Cheshire cat .great people I found . Rudyard

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I am not the one who told the story, however, I do have documents that places Major Richards in the village from whence the gun came from. The Major died year before last and this came from his estate.
If you are that knowledgeable, then yes, I would love to hear your interpretation of what, where, when it may have come.
So as to not complete highjack the original thread, I will send the pics to you via CONV.

Okie Hog said:

What brand is the rifle? That will tell us the size of the nipple threads.

As a mechanic I've used lots of Heli-Coils. I've long had all the expensive Heli-Coil tools but still don't like the things. About 50 years ago i discovered Keensert thread inserts. Simply drill the hole to a standard oversize, thread and install the Keensert. Those really sound like the ticket. At those prices, you could order up 2 or 3 and get some practice on some old hunk of steel before trying it on your gun. There's another insert we used at a school I taught at. We used them on transmission cases and engine blocks. G M uses them on factory authorized repairs. It's called a Time-Sert but requires a heli-coil tap ( same thread pitch as heli-coil) and a reamer. Kind of expensive. Only reason we used them was because we did lots and lots of them. I'd go for the keen-sert.

i've repaired a few muzzleloaders this way using a 3/8X16 Keensert which has 1/4X28 internal threads.

https://www.carrlane.com/en-us/prod...all/key-inserts-thinwall-stainless-steel-inch

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Somehow my reply got interwoven into okiehogs post!

My post is this one:
"Those really sound like the ticket. At those prices, you could order up 2 or 3 and get some practice on some old hunk of steel before trying it on your gun. There's another insert we used at a school I taught at. We used them on transmission cases and engine blocks. G M uses them on factory authorized repairs. It's called a Time-Sert but requires a heli-coil tap ( same thread pitch as heli-coil) and a reamer. Kind of expensive. Only reason we used them was because we did lots and lots of them. I'd go for the keen-sert."