Touch hole liner - ok solution?

[coopersdad]

I'd appreciate some advice on my current project. I'm rebuilding my first rifle from 20 yrs. ago, so many mistakes....One of them was drilling the touch hole liner hole a bit too low.   I made the liner from a 1/4" x 20 stainless set screw.  It looked awful but worked sorta ok.  The hex key hole was at the bottom of the pan and eventually made a nice ugly gas cut in the pan. Barrel is a Green Mt. .32 cal, 13/16".  The hole:



I know the very best solution is to cut and rebreech, but I'd like to avoid that if possible.   I can't use a new 1/4" White Lightning or other liner as the threads are finer.  I don't think a 5/16" liner will work, it may hit the breechplug, and the hole for it would be below the bore; not sure of the ramifications of that but I don't think good. 

So my thoughts:

- make a liner from a 1/4 x 20 stainless bolt, drill and cone the inside.
- fit it so the unthreaded portion seats in a countersink on the barrel flat.
- peen it a bit if needed (will stainless peen?) to fill the countersink, file flush.  Use some red loctite too for insurance.
- grind the pan to remove the gas cut and make the hole "higher" in the pan, although I hear that isn't as critical as I thought.
- There are 4 1/2 to 5 of those coarse threads engaging the barrel wall.  Enough?

Bad idea or reasonable?  Thanks!!




   

[Keb]

I've done this for bad hole placements when converting from a drum to flint & it will work out just fine. I used Ampco instead of stainless though.  Drill your vent hole in the proper position. It doesn't have to be in the center. Just my opinion.

[rich pierce]

I think all that would work but see no need for stainless.  The challenge will be that you need the touchhole to be offset from the center of the plug.  I would make a plug from threaded rod, screw it in the right distance (check from the breech and by running a wiper down the barrel). Then mark how far it needs to go in.  Cut the rod a little long, slot for a screwdiver, and screw it in, re-check its in the correct distance.  Peen it to lock it down, file it flush.  Then mount the barrel and lock and see where the touchhole belongs, drill it, and cone from the inside with one of those little tools.

[smylee grouch]

There are quite a few gunsmiths on this forum that could make a new breech plug for you that would fix your problem. Cut barrel off in front of vent hole, make and fit new plug so that it is the same length as existing barrel assembly in octagone shape with tang, (noch style plug). Then you can drill a new vent hole in the right position. I have had this done and it works great.  Smylee

[Bernard]

If you really want to fix the problem and have the tools to do it you can have an old 3/8 end mill sharpened to the size of an I drill .2720. Then mount the barrel in your vise on the vertical milling machine and machine a hole for 5/16-24 threads just far enough ahead and up so as to add all to increase in hole size to the top right of the present hole, while only removing a part of the threads on the bottom left of the existing hole. then cut threads using a 5/16-24 bottoming tap but don't go all the way through. Now make a touch hole liner from the material of your choice. I like the design of Chambers Lightning touch hole liners but don't drill the hole from the inside as Jim does 'cause you don't want the hole in the middle of this liner. Install the liner, cut it off, file it flush with the barrel, assemble the rifle, locate the best location for the touch hole (I like a bit high and to the rear of the centre line of the pan), mark the location, take the barrel out of the stock, mount it on the drill press or milling machine and drill your new touch hole.
If you don't have the tools you can take the barrel to a machine shop and ask them to bore a hole for 5/16-24 threads and move the centre of the hole forward and up as described above.

[Daryl]

I've done this for bad hole placements when converting from a drum to flint & it will work out just fine. I used Ampco instead of stainless though.  Drill your vent hole in the proper position. It doesn't have to be in the center. Just my opinion.

That is how Taylor and I remedied a too-high threaded hole in a .32X13/16" bl. I do believe we used stainless or maybe a schedule 5 bolt, turned the appropriate threads (as the original drum), coned on the inside and drilled the vent hold on a slight angle from the sunset position - Since the flash 'channel' to the inner cone is so short, it works perfectly.

If possible, deepening the pan is also a partial remedy.

[kutter]

I'd cut a shallow square counter sink into those existing threads. Big enough to clean up the existing tapered cut and just a touch more.

Make a new plug  with the 1/4x20 threads and the new 'head' to fit the new square edge countersink.
Leave the head a bit long and cut a screwdriver slot in it , but not so deep that it will show when the plug is seated and filed flush.

Seat the plug tightly multiple times to make sure it is seated all the way. Then file it down as far as possible but still leaving enough of your screwdriver slot in place so you can remove it.
**This will tell you how deep you need to cut it in the first place**

Mark the plug on the inside of the bore where it enters so you can trim it to the curve of the bore.

With the plug still in place and as flush as possible on the bbl,,place the lock back in position and mark the location of the flash hole.
The lock won't sit perfectly flat as the plug is still a bit high,,but will sit 'in place' and the flash hole can still be accurately marked.

Double check it and make a small 'witness' mark along the side the plug and bbl flat to indicated how far the plug is turned into place.

Remove the lock,,remove the plug.

Drill the flash hole where you have it indicated from the front.
Trim the back end to the arc you marked while it was in place to match the bore.
Now counter drill from the  back side for your liner purpose.

Reinstall plug in bbl tightening to the witness mark.
File flush to the bbl flat. You can lightly peen the head of the plug into the countersink just before it's flush for perfect fit between the two surface edges.

If you use regular steel for the plug, you won't even see it when re-browned/blued.
I use plugs all the time to repair unwanted holes in cartridge guns.

[coopersdad]

Thanks for all the great replies.  I am lathe- and milling machine-less, and no one around has one (who I'd trust doing the work or who does anything other than turn brakes) so I must go with the lower tech solutions.  Sometimes half the fun is figuring out how to do it with what you have.