Using a lathe to trim cases?

07 December 2014, 20:04

Dan416

Hello, does anyone have any cleaver, simple technique on using a lathe to trim cases? 505 Gibbs won't fit in the case trimmer. I could make parts for the trimmer but I thought I'd go straight to the lathe. A mandrel in the drill chuck in the tailstock (with a relief cut for tool access) would be easy enough but I'm wondering how to consistently hold the base in the 3 jaw for length. Or maybe someone has a better idea all around.

07 December 2014, 20:19

Pa.Frank

I think Little Crow Gunworks may make one that will work for you... If they don't have a stock trimmer, they will make you one, and for a lot less than the cost of a lathe... and their trimmers are a joy to work with.

07 December 2014, 20:40

Bill Leeper

quote:
Originally posted by Dan416:
Hello, does anyone have any cleaver, simple technique on using a lathe to trim cases? 505 Gibbs won't fit in the case trimmer. I could make parts for the trimmer but I thought I'd go straight to the lathe. A mandrel in the drill chuck in the tailstock (with a relief cut for tool access) would be easy enough but I'm wondering how to consistently hold the base in the 3 jaw for length. Or maybe someone has a better idea all around.

Chuck the cutter shaft and pilot from your trimmer in the three-jaw. Now, make a piece which encloses the head of the case and holds it in alignment. This piece will be held in the tailstock drill chuck. Use the tailstock to feed the case into the cutter the required amount while holding the case from turning with you fingers. You won't be able to cut very fast unless you have a heck of a grip. Of course, you could use a set screw in your holder but you risk damaging the brass. Another alternative is to make a collet holder. You may also hold the case with a pair of padded pliers.
You can also make a shellholder like those which were sold by Lee for use with their case trimming system but by the time you do that, you could probably modify your trimmer.
I wish I could doodle on the computer because I can think of a half dozen simple fixtures but lack the ability to paint a sufficiently detailed word-picture. Regards, Bill

07 December 2014, 22:26

eagle27

To trim my 404 cases which wouldn't fit my trimmer I just made up an adjustable trim die to fit in my press and then file the cases to length. You obviously have a lathe so could simply make one from a 7/8" bolt or thread some stock and bore out. Very rarely need to trim these cases.

08 December 2014, 00:39

Dan416

My trimmer cutter maxes out at .45 cal. So i'll need to use a lathe tool.

I think one trimming will do for many reloads. I don't full length size.

08 December 2014, 02:41

TomP

I made a threaded shaft that fits a shell holder from a reloader, and used a carbide lathe cutter on the cross slide. I place the case head in the shell holder and screw it finger-tight, then start the motor and move the cross slide. It is reasonably consistent, and with a mandrel in the case mouth ( like a slightly undersize bullet ), you can turn the neck while it's there.

08 December 2014, 02:59

delloro

quote:
Originally posted by Dan416:
Hello, does anyone have any cleaver, simple technique on using a lathe to trim cases? 505 Gibbs won't fit in the case trimmer. I could make parts for the trimmer but I thought I'd go straight to the lathe. A mandrel in the drill chuck in the tailstock (with a relief cut for tool access) would be easy enough but I'm wondering how to consistently hold the base in the 3 jaw for length. Or maybe someone has a better idea all around.

lee might be able to make one for you.

08 December 2014, 20:14

Doug W

The rim held in a 5C collet would be better than a 3 jaw. You can buy soft machinable collets in 5C to machine to the rim.

A 3 jaw doesn't run very true, or repeatable.

If you don't have the 5C accessories for you lathe, you could hold the 5c collet in a square collet block and trim in the drill press.

08 December 2014, 20:35

L. Rivard

I have used the Lee case specific trimmers on a lathe by machining soft jaws for a three jaw chuck to hold the case head and holding the cutter in the tailstock. Works slick.

09 December 2014, 23:41

Dan416

quote:
Originally posted by Dan416:
Hello, does anyone have any clever, simple technique on using a lathe to trim cases? 505 Gibbs won't fit in the case trimmer. I could make parts for the trimmer but I thought I'd go straight to the lathe. A mandrel in the drill chuck in the tailstock (with a relief cut for tool access) would be easy enough but I'm wondering how to consistently hold the base in the 3 jaw for length. Or maybe someone has a better idea all around.

10 December 2014, 13:05

Rusty

I have the "Little Crow" WFT and it works. I'm sure that they could make you an insert for their Big Boy Cutter. If you ever use one of their trimmers, you will never go back to chucking on up and cranking a handle! Give them a call. The worst they can do is say "we can't do that".
WFT2

Rusty
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10 December 2014, 22:14

JohnD

I've used the Kwick Case Trimmer from www.possumhollowproducts.com in my lathe for .308 Winchester. It indexes off the shoulder so you don't need case holders. They don't list .505 Gibbs (Shocking, right?) but they say they'll make specials.

If you're making your own the concept should work.