solid breech

[Kelhammer]

So I am going to be working this Saturday, and may have the time to drill out some bar ends of 8620.  I have one about 7 inches long I did a few weeks ago, that just screams "make a pistol barrel out of me."  So as I am thinking about making a few more, I wondered what the down side would be to stop short, of drilling clear thru the bar stock.  The idea being I would not have to make breech plugs for them.  I could easily leave material for a tang, but the barrel would be a one piece construction.  I had not planned on rifling, so what would be the down side?  I have drills to do this in .500 and .625 diameters, to a depth of around 10 inches I think.

Andrew

[Don Getz]

Andy..........One thing for sure, you won't get any leakage around the plug.    Don't see anything wrong with doing it that
way, as long as you are satisfied with the finish that you will get with a drill.   There could be problems with that situation
on down the road if you dry ball it, and can't pull the ball, other than that I can't see any problems............Don

[Levy]

I brought a brass pistol barrel to the CLA last year that was recovered from a 1715 Spanish shipwreck off Ft. Pierce, FL.  the barrel was constructed in the same manner that you are contemplating, with no breechplug.  It went to a Miquelet pistol and the tang screw came in from the bottom.  Ed Rayl is making some copies of the barrel for me, but they will have bronze breechplugs that screw in for the reason that Don G. mentioned.

James Levy 

[omark]

 the inside finish could be cleaned up with reamers and honing.     mark

[Rasch Chronicles]

Kel,

Out of curiosity, how are you assured that the bore is straight? Wouldnt you have to turn it on centers from both ends? I'm not a machinist, though it is often assumed that I am because I once played one on TV...

Best Regards,
Albert “Afghanus” Rasch
The Rasch Outdoor Chronicles™
The Best Turkey Hunting Tips!

[Jerry V Lape]

If the need ever came to unbreech the barrel, couldn't he drill it on through and put a conventional breech in then assuming he made provisions with the tang to make that relatively convenient.

[keweenaw]

As Don pointed out the drill will leave too rough of a surface.  If you're going to do this you'll want to ream them after you drill to clean up the bore.  It is pretty difficult to drill a 10" hole that will still be concentric with the outside of the work at 10".

Tom

[Acer Saccharum]

It's awful nice to be able to ream straight thru.

Also consider if it DOES run off, you can turn it on centers to tru it up.

All said and done, it may be less work to drill thru and plug, in my mind, anyway.

Tom

[Jerry V Lape]

Well you can tell I am not a machinist.   

[Don Getz]

Another thought.   Aren't cannons made this way, by that I mean with a solid breech?    Remember, this guy is only making about an 8" barrel, smoothbore to boot, so why worry about accuracy.    As long as it is smooth enough to load,
go for it.    It's going to be real cheap to start with, don't stop with one, make two...............Don

[Kelhammer]

Run out on my lathe is usually a non-issue, well as long as I do my part.  The test blank I drilled a few weeks ago has near perfect concentricty on the start end, and a tir of .002 on the back end.  I am not yet a gun smith, but for what I want, in this case, I figured that would be close enuff.  For what its worth, I could insert a drill blank into the piece after drilling, but before any OD profiling began, and get an idea on run out that way.  Spinning the part in a v-block, on a surface plate, checking the drill blank for runout with an indicator.

This idea began when I was given a test drill at work.  OAL is around 10 inches, so I stand corrected, I can go 6.5 inches in depth, from each end if needed.  This thing is solid carbide, with thru coolant, I think I ran the part 2200rpm with a feed rate of .005 per rev, which was on the bottom side of the suggested speeds and feeds for the tool.  On 4140 pre hard, I got a hole with a shiny finish on the inside.  It looked almost like it had been ground.  Saddly the 8620 stock I have does not leave as nice of a finish in the hole.  Still it is as good as most reamed finishes, and with a little emery on a 12 inch ejector pin, I am sure I can put a glass finish inside the bore.  Anyway these drills work great, it takes just seconds to drill to depth, and pull the tool out.  When asked if I wanted any, I suggest a .500 and a .625 and I ended up getting 2 of each.

I started setting some things in place today as I left, so as long as the boss stays home tomorrow, I should be ready to sneak it in    If I get a few started, I'll let ya know how they turn out.  All I plan on doing is truing up the OD, and getting the holes in.

Andrew

[omark]

as far as runout, you will undoubtedly be boring before cutting the tang. just orient the barrel so the bore runs up, as we used to do the old barrels that werent true, then make the tang.    mark

[Kelhammer]

I could not be happier with today's work.  I have a nice blank with a 6.3 deep hole in it.  I would like to make this into a octagon to round barrel, is there a good resource for studying pistol barrels?  At least the OD contours.  Maybe sketch out what looks nice, and take measurement from the sketch?  It would be nice to not screw it up now.

Andrew

[Kelhammer]

In progress.

[Hungry Horse]

I have a trade pistol I made from a bunch of old kit gun parts. It has a round  .68 cal. sea service pistol barrel that is stamped Japan on the side. It is a solid breech as you describe. I have never had a problem with it. Its the best parade gun I've ever owned. I shot forty one blank shots in a row with it at Crescent City several years ago, without a misfire. That is with an old CVA mountain Rifle flintlock in it,  to boot.

                        Hungry Horse

[James Wilson Everett]

Be careful with the reaming a blind hole, that is a hole that is closed at the end.  With a twist drill the chips are pulled back out and away from the drill point, this is good.  A reamer tends to push the chips out in front of the tool, leaving a wad of chips at the bottom of the blind hole.  When you get the reamer close to the blind end of the hole, be sure to clear the chips by more than just pulling the reamer out.  Try to actually look into the hole and fish out any chips that remain in the hole.  A 18th c ramrod worm is really an ideal tool for this.

Jim