The Accurate Reloading Forums
lathe question
11 July 2004, 04:09
GonHuntinlathe question
I know this is probably a dumb question, but if you don't know, you don't know!

How do you grip a tapered barrel with the chuck?
11 July 2004, 04:33
ASS_CLOWNNot a dumb question at all! I am immensely interested myself in hearing how it is done, correctly.
I know how I would do it, but it would not involve a "chuck".
ASS_CLOWN
11 July 2004, 06:17
johnnynighthawkI'm not a gunsmith, but as a machinist I would make a collar out of aluminum. Taper the inside of the collar to match the barrel, then split one side so it will tighten up on the barrel when you close it in the chuck.
One way, the way I do it if I need to chamber in a steady, is to cut a one inch or so straight section where the muzzle end is. This end gets cut off anyway so I turn it into a straight section that is easily gripped by the chuck. When done, it gets removed and a nice crown is added. Do this before shortening the barrel to its final length.
11 July 2004, 08:56
Alberta CanuckI gather you have a lathe with a spindle hole that is too small to push the barrel in to the point where you can grip parallel sides of the barrel.....
What I do if the taper is not too severe, is to wrap the barrel with about 6-10 wraps of old used crocus cloth, grit side OUT. The 4-jaw chuck compresses one end of the crocus cloth more than the other, but both give firm grip of the barrel.
AC
11 July 2004, 10:01
BBeyerIf you have 2 piece jaws you can make a set of soft jaws of aluminum and taper them with the cross slide set to the rirht angle and a boring bar.
11 July 2004, 10:22
GonHuntinActually, I don't own a lathe and I'm not a machinist.....I took the barrel to a friend who is a machinist and he did what I needed done in about five minutes.......the big problem is that there is no parallel point on the barrel.....he said if the job had been more complex, that it would have been a problem, however, since I just needed a few thousandths removed from the shoulder of a 22 rifle barrel (so the front sight would index) it wasn't a big deal.
So, do most gunsmiths who rechamber a used barrel do it in a steady rest and turn it with a dog? I see photos on different gunsmith's websites showing barrels being chambered and the barrel is through the headstock and held in a spider and the chuck.......I can't believe that some of these barrels aren't tapered/contoured??? I'm not a machinist and certainly not a gunsmith, so some of this is a mystery to me........sure would be enlightening to hang around for a few weeks in a good gunsmith's shop!
Thanks! Mark
11 July 2004, 15:16
jeffeossoMark,
in theory, the barrel is parallel with the bore, at the shank.. and can be held (dog, steady rest, at the chuck, or even a 5c collet chuck, and indicated for runout.. or the runout can be measured from the CHAMBER, but that's a little tougher......
you then have a pilot on the chamber reamer, and loads of cutting/tap lube....
aint easy, but it aint THAT hard...
jeffe
11 July 2004, 23:22
wallywI use lead sheet to cushion barrel against chuck jaws.
If you put a layer of "Bondo" on the barrel and turn between centers you will have a straight section that
is concentric to the bore. The same trick will work with octagonal barrels, or provide a pad for a steady
rest. When you are done alittle hgeat will remove it. One danger with chucking on a taper is pushing the barrel
into the head stock when chambering.
Good luck!
13 July 2004, 05:43
rick0311You can also tap/thread a piece of straight/round stock to thread onto your tapered barrel and grab that, rather than the barrel itself, with the chuck jaws.
Rick
13 July 2004, 06:09
Alberta CanuckIf there isn't ANY parallel part to the barrel, how is it held in the action? Surely the barrel has a parallel shank.....?
Anyway, is generally no big deal...probably any one of the suggestions mentioned here will work. For that matter, if desperate, one could wrap 3" or so of the barrel length in a piece of cardboard cut to make one or two complete circuit(s) of the barrel, then dusted on the inside with rosin. Four-jaw chucks generate a LOT of force when torqued up tight in the centering process, so they will compress the cardboard to where one end of the cardboard is very thin and the other not quite so thin, but both ends still very tight.
Very few rifle barrels have a taper so rapid that there is nowhere along the length that sufficient holding can be achieved.
Centering on the bore is also dead easy, given an indicator with a long stem, or the use of range rods. Personally, I prefer range rods such as those made by Dave Kif at PPG for almost nothing in cost.....
I have rebarreled, refitted, and rethroated a goodly number of rifle barrels over the years, and never do one between centers. I always put them through the headstock and spider, center with range rods on both ends, and haven't found one yet that couldn't be grabbed adequately to cut without marring or slipping.
Would also be possible with a chuck like a "Set-True" 6-jaw, used correctly.
AC
You can use pennies as the cushion, use your spider to make sure it runs true. Tape them on with masking tape. Aluminum can stock works fine for parallel surfaces. Normally you would not grab it by the tapered portion. When I do chamber or threading work I grab it by the parallel portion at the chamber end. If for some reason I want to let it hang out and use a steady rest over the chamber I figure on marring it up. Even with bearings on the steady rest it will mess up the finish. I try not to do that. For most jobs I tend to use beer can stock and a four jaw. For tapering a barrel that is a little different. I use a center in each end and a lathe dog. I offset the tailstock the required amount. Then set up the steady rest in the middle to prevent oscillations. Turn one side then pull the barrel out and move the saddle to the other side of the steady rest and turn the other side. Finally slowly remove the remaining portion that the steady rest ran on. I "drawfile" with a belt sander then use a spinner to polish. Mostly you are bettter off to get preturned barrels. It is a hassel to do it yourself.