Helicoil repair

[user 34300]

When renewing the threads, or drilling and tapping a new drum hole, use a milling machine or stout drill press. After determining the drill will land in the exact middle of the old hole and you are 90* to flats, put in an undersized bit and go very slow. Then put in the tap drill bit. Then use the quill to guide the tap dead straight. It does not hurt to stop the tap a bit short so that the end of the drum snout has a slight interference fit in the threads. At no time break the set up. No not free hand it.

I have put Loctite shaft sealant on the drum thread for a nearly permanent assembly.

After the drum in correctly installed remove any drum snout that is protruding into the bore with a Dremel ball stone. Make brass sheet tube with a hole in it to protect the bore. There is no reason to maul the bore. Re install the breech plug.

Do a good job, if a drum comes out you may injure or kill someone.

 

[Jetmech]

When renewing the threads, or drilling and tapping a new drum hole, use a milling machine or stout drill press. After determining the drill will land in the exact middle of the old hole and you are 90* to flats, put in an undersized bit and go very slow. Then put in the tap drill bit. Then use the quill to guide the tap dead straight. It does not hurt to stop the tap a bit short so that the end of the drum snout has a slight interference fit in the threads. At no time break the set up. No not free hand it.

I have put Loctite shaft sealant on the drum thread for a nearly permanent assembly.

After the drum in correctly installed remove any drum snout that is protruding into the bore with a Dremel ball stone. Make brass sheet tube with a hole in it to protect the bore. There is no reason to maul the bore. Re install the breech plug.

Do a good job, if a drum comes out you may injure or kill someone.

Thank you sir for the instructions. I don’t have a mill but I do have a sturdy drill press, precision bits, taps and willingness to do the job correctly.

Thanks again

 

[Art Caputo]

I had poor results using the Helicoil with engine repairs when heat and pressure is present. I suspected the issue may have been the difference in the expansion coefficients between the Helicoil and the adjoining parts(ie. Oil pressure sending unit, engine block, and Helicoil). It would hold well until the engine approached operating temperature…then seepage would occur. Based on this experience, I would quite hesitant about using a Helicoil with the breach plug on a muzzleloader……..IMO.

 

[Pratt]

I have use Heli coils in service. I never liked the idea. Fill the hole and tap it.

 

[user 34300]

Structural welding is a specialized business. The chances of a less than perfect weld is good. I would go up one size, as needed, and make it right in virgin steel.

The Harbor freight transfer punch set has many uses. One is to put the best size in you drill chuck and determine the exact center of the existing hole. Once you have that do not break the set up until after the tapping is done. .

 

[Bad Karma]

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

Never get involved with blond women in the cutting horse scene…

 

[ZUG]

Heli-Coils and other such items have their place, but I don't think the ML barrel is one of them. It may work for a while but the corrosion from the residue of the black powder and water when you clean the gun will find its way into and under the Heli-Coil and cause corrosion which will eventually cause the drum to separate from the barrel.

 

[IanH]

....that's why I said install it with epoxy, solves the thread corrosion issue and the remove to clean issue at the same time. Heli-coils will work for this, but it would need to be installed by someone who knows exactly what they are doing. Done correctly, it will be stronger than the original size drum threads, but likely not as strong as drilling out and threading oversized. For home-gamers, forget I mentioned it.

Oh, and Jasper engines, every single thing Jasper makes that I bought (about two dozen units over a 3 year period) had major problems related to simple jobs done poorly. Jasper flew me up to their plant for a VIP tour along with a couple of others from my area as part of their promo deal. Their plant is nice, everything seems in order, then you actually get their product and find the stupidest things wrong with it, like clueless high school kids trying to fix a damaged part with hardware store stuff they are unfamiliar with. It all cost us a lot of money with comebacks, lots of diagnostic time, and replacing units for free, so I eventually fired them and went exclusively OEM for reman units.

 

[Indy Durtdigger]

....that's why I said install it with epoxy, solves the thread corrosion issue and the remove to clean issue at the same time. Heli-coils will work for this, but it would need to be installed by someone who knows exactly what they are doing. Done correctly, it will be stronger than the original size drum threads, but likely not as strong as drilling out and threading oversized. For home-gamers, forget I mentioned it.

Oh, and Jasper engines, every single thing Jasper makes that I bought (about two dozen units over a 3 year period) had major problems related to simple jobs done poorly. Jasper flew me up to their plant for a VIP tour along with a couple of others from my area as part of their promo deal. Their plant is nice, everything seems in order, then you actually get their product and find the stupidest things wrong with it, like clueless high school kids trying to fix a damaged part with hardware store stuff they are unfamiliar with. It all cost us a lot of money with comebacks, lots of diagnostic time, and replacing units for free, so I eventually fired them and went exclusively OEM for reman units.

When you said Jasper engines I cringed. Textbook examples of how not to accomplish thread repairs and sometimes and engine rebuild in general.

 

[IanH]

When you said Jasper engines I cringed. Textbook examples of how not to accomplish thread repairs and sometimes and engine rebuild in general.

HA! Yeah, I cringed too when French Colonial brought it up, haven't had to deal with their junk in a few years and had forgotten how much I don't miss it.

 

[Tumbledown]

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.

Ban muzzleloaders from public ranges, because you never know who might be trying smokeless.

Ban reloaded casings, because you don't know if someone really knows how to reload ammo.

Seriously, when was the last time someone's drum blew off and hit someone?

 

[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.

If I were you and I wasn't a gun smith I would carry it to one before I screwed up big time. This isn't a job for a shade tree mechanic. This shooting from the hip will get you into big trouble eventually.

 

[Rebel bull]

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?

no !!!! not!!! ever!!!

 

[BS]

Why not just get a new drum with the next size bigger threads?

 

[nkbj]

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'

Yeah, that was my thought on the matter.

Helicoils are good for what they're good for, functions that actually are not always repairs. But not for this.