AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: David Veith on September 10, 2008, 10:58:44 PM
-
Said it all in the subject. And yes I do have a lathe. Just never done one.
David veith
-
I would first turn a bore dia. rod a couple inches long from aluminum. Make it a no wobble fit for your bore. I like to make it a thumb press fit. Chuck your barrel in a 4 jaw chuck and indicate the rod and get running true within .0005 . Remove the rod , face the barrel and cut the crown chamfer. The angle of the chamfer is really subject of debate. But I can't see you going wrong with 45 degrees. Just deeper than the grooves by about .010
P.S It.s also a good idea to use 4 small wooden wedges to center the other end of the barrel in the head stock. A bit of gentle tapping and some shipping tape will hold them.
-
If you have to struggle (like most of us peons) with hand tools, Ol Chuck Dixons book explains this quite well!
Short reponse is clamp your barrel in a vise padded with wood blocks. Assume you have checked the muzzle for square. Get hold of a hand brace and chuck up a medium cut or finer ball cutter with the rod for the chuck! Have your barrel near perfect in vertical. Cut your campher slowly as you walk around the vise (or walk nearly around if your vise is attached to your large workbench). Then chuck up your brass ball with the rod attached and coat with fine valve grinding compound polish til satisfied. Then wrap some 400 or 600 cloth around that brass ball and finish the polish! You could finish polish with wet emory on your finger end as some folks do.
Like they say 'works for me' ;D
Ooops now I notice your question referred to recrown rather than crown. Well then don't do the ball cutter thingee just the rest!
-
I use plug guages i bought from harbor freight to indicate the muzzel in the four jaw chuck. Turning a plug from aluminum will work fine the guages are just quicker. Also get the tail end of the barrell running as true as possible. When making the cut, cut from the inside out and you wont raise a burr on the muzzle or rifling. I always used 11 degre on centerfire but 60 or 45 for muzzleloaders. Use a fairley fast rmp and slowest feed.
-
To add to and agree with Roger's method.........Having a lathe makes it easier, but it if not, remember, the face of the muzzle being square is not near as important as the chamfer being concentric with the bore.
Bill
-
You guys are getting too paranoid again. When we bought the Paris barrel business, crowning the barrel was the last
thing they showed us how to do, and was the last thing they did in finishing a barrel. It was done with a brace and a
countesink tool. We merely placed the barrel in a vise horizontally, then carefully lined up the countersink in the brace and turned it a few times, took all of 30 seconds to do it. When we moved the shop and started making barrels on our
own we used the same procedure for a while, then changed to doing the countersink, or crowning, while the barrel was
still in the lather, after we had turned it, a much better way. However, there really is nothing wrong with the way they
and we did it with the old brace and countersink tool......just try to get it lined up real well........Don
-
If you use a ball file, rather than a countersink, it will self center and cut more true than a lathe can. The muzzle flat, needs not to be perfect by this method, but you will have a very slight radius in the cut, that may require just a tad more effort to start your ball until the edges break in. You can speed this process by lightly twisting a piece of 400 grit, on your finger tip to break the sharp edge.
-
Don,
I'm one of those paranoid guys but I'm coming around. My heart went into overdrive as Bookie showed me how to crown a barrel just and you and Roger described except he has a small level attached to the chest brace.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi7.photobucket.com%2Falbums%2Fy298%2FPackdog1%2FRifling%2520barrel%2FBookiesday2.jpg&hash=1941a58bb7c3f7b440d13da2055385329cbe08b6)
-
Well guys I was raised by a old school tool and die machinist and if I don't get everything to within a half a thousanth I'm afraid i might get smacked in the back of the head!! :D :D
-
I was taught by Willy Boitnot the armor for the international Muzzleloading team way back when. He does very similar to Don Getz but uses a ball stone on a hand brace. I have been doing them that way ever since. Takes all of a min and you can have one done before the lathe guys can get centered. The ball self centers itself.
-
I use plug guages i bought from harbor freight to indicate the muzzel in the four jaw chuck. Turning a plug from aluminum will work fine the guages are just quicker. Also get the tail end of the barrell running as true as possible. When making the cut, cut from the inside out and you wont raise a burr on the muzzle or rifling. I always used 11 degre on centerfire but 60 or 45 for muzzleloaders. Use a fairley fast rmp and slowest feed.
I have done ML crowns on the lathe as well and it works very well. But the setup takes time. But you can do a 2-3 angle job that really looks nice if you want.
Almost anything will work for a ML. Anyone with a lathe can make a piloted tool and then double stick wet or dry paper to it. Drive it with a brace or an electric drill.
Or cut teeth in it with a file or graver, or use a stone, or a counter sink with or without wet or dry paper.
Almost anything will work. The ball stone is a good idea but it needs to be matched to the bore to do it right. A ball for a 54 won't do a 36 properly.
I have done this a number of different ways and they all work fine if the worker is *careful*. I dislike deep crowns but do think a short funnel or relief to .030-.050" below the crown helps a hunting rifle and if not over done does not hurt accuracy. Really deep funnels I am not so sure of. Nor would I remove the lands completely at the muzzle.
Also the width of the grooves will to some extent determine the amount of work needed on the crown.
I tend to put deeper reliefs/funnels in pistol barrels since they are harder to load due to the size of the firearm.
Dan
-
Brownells sells a piloted hand tool that cuts a 45 degree crown. I make up brass pilots on a lathe to fit any bore diameter required. Takes a few twists of the hand and it will cut as heavy or light a crown as you like concentric with the bore. The also sell one that is used to square the end of the muzzle with the bore, but it's only about 3/4 inch in diameter. As a consequence, it won't cut the entire surface of most ML barrels completely. However, it established a muzzle plane perpendicular to the bore and the rest can be cleaned up with a file quickly. (If you don't have a lathe or don't want to take the set up time.) I also use the spherical stones (and / or brass balls of various sizes with valve grinding compound) to create or polish the crown.
-
If you use a ball file, rather than a countersink, it will self center and cut more true than a lathe can.
I can indicate a bore within .0002 " fairly easily on my lathe, I don't think I could come close to that kind of accuracy with a rotary ball file or stone. I am not sure that it makes that much difference on a round ball gun anyway, some of my patches will vary as much as .004" in thickness across the width of the patch. I just don't think you can get something too precise. I am fortunate to have the tooling to do pretty close tolerance work so I use it. If I didn't have the stuff I would use a 60 deg. countersink and be a happy camper. I can't shoot well enough to tell the difference anyway!
-
You guys are talking about getting a barrel centered on the lathe within a few thousands....not sure that is really necessary. The first gun I ever built was with a Douglas barrel. They had a lot of stuff stamped on the muzzle end so
you had to cut the barrel off. I did that and filed it flat and square. I then took needle files and rounded each groove and
land, by hand, to accomplish a crown. The gun shot great, and I won a lot of stuff with it......doesn't that kind of make
you feel that you are overcomplicating it?.................Don
-
Don - I was going to add my method, but will recall a re-crown I did for a guy with a TC years ago. He couldn't keep 5 shots on a target with the thin patches he said he had to use. I pulled out my pocket knife, cut a sliver of steel from about the crown on his barrel, then a short old piece of emery from my pouch, and with my thumb rotating the emery and the barrel, I smoothed the cut. From then on, he was a new competitor with his heavier denim patches. This is about as rough-shod as a re-crown can get, but shows there isn't any rocket science needed.
-
Don - I was going to add my method, but will recall a re-crown I did for a guy with a TC years ago. He couldn't keep 5 shots on a target with the thin patches he said he had to use. I pulled out my pocket knife, cut a sliver of steel from about the crown on his barrel, then a short old piece of emery from my pouch, and with my thumb rotating the emery and the barrel, I smoothed the cut. From then on, he was a new competitor with his heavier denim patches. This is about as rough-shod as a re-crown can get, but shows there isn't any rocket science needed.
I think you are correct in this. I don't think the PRB cares a lot about the crown so far as absolute precision it only need be good enough. I have also reworked/polished crowns with wet or dry on my thumb.
But its possible to make them look better with a little tooling.
Firearms loaded with a false muzzle or from the breech need no crown at the muzzle at all and *probably* actually shoot better this way.
Dan
-
I used to use one of those Dremmel 1/8inch shaft V grinding bits to crown the bore and had no problem and once or twice a countersink. Didn't mention it before becasue everyone seemed to want to do it the harder ways. I didn't even polish a couple afterward but let the shooting work them in.
DP
-
I have done some super crowns on the lathe, while the barrel blank is still in the round. I would cut a chamfer on the
muzzle with a countersink, then will take a three corner scraper and actually round all of the corners to make a beautiful
rounded crown, then polish with scotch brite or fine emery. This is done before the barrel is reamed or rifled, but the end
result is superb. I think I did one like that for Brian and Taylor.......Don
-
What do the old guns have for a crown? I don't recall seeing the deep crowns like modern barrels come with. Of course, I haven't seen all that many old guns either!
Andy
-
They were often funneled and the grooves filed out to the muzzle it would seem and many did not shoot as tight a ball fit as we do. Partly due to the land/groove ratio on the early barrels.
Dan