Case trimming in the lathe

[country gent]

Several things speed up using the lathe for trimming. mount the cutter in the headstock ( this allows you to not have to stop and start the lathe spindle every time). A fixture to hold brass in the tail stock or carriage. with compound set 90* (parallel to lathe bed. and cases held in a fixture this would provide fine adjustment for tje cuts length. A stop on the lathe bed for carriage to butt against is needed. The fixture needs to be a quick release clamp. think a brass rod bored for the case split and hinged you can open it set case in and pinch closed with fingers wheile cutting. Set up would require indicating the case into dead center then not touching anything other than carriage feed wheel and compound for fine adjustments. An small angle plate or alloris tool block could be set up to do this. Making the tooling would be an investment in time and material though. For most trimming the simple cutters work well. a drill press is cheaper and eaasier to set up. ( a cheap bench top drill press can be dedicated and left set up even)

[rbuck351]

Actually what I said was 15/20 seconds for trim, deburr inside and out and polish the case mouth but read it anyway you want. And that includes mounting and dismounting the case.
Banger ,you have me curious. What kind of Lee trimmer are you using and how do you hold the case to spin it? Could you describe your process a bit better?

[Idz]

To trim down 24 ga brass for forming into 577/450 Martini-Henry I use my 3-jaw chuck on my 9x20 import lathe. The case head drops nicely into one of the notches in the jaws so I can gently tighten on the OD. Then take very light cuts to trim to length.

[Tackleberry41]

I think with the 577 snyder, it would be faster to cut most of it off with a dremel, then the last little bit with a trimmer. I know an issue that comes up is finding a trimmer the 24ga will fit in. It wont fit in my universal head RCBS trimmer. I got lucky and bought the lee hand trimmers for my 577/450 before they stopped making them. Thats what I do, cut most of it with a dremel, then the last little bit with the trimmer.

I have a lathe, and do not see how without special tooling it could be faster at trimming. I have trimmed a case here or there, usually something like turning a rim down, and its not fast. But I am not willing to spend a bunch of time messing with modifying a chuck or making some tool to do it. I can clamp my old RCBS trimmer down and away you go. Or the Lee trimmers for some stuff.

[bangerjim]

Actually what I said was 15/20 seconds for trim, deburr inside and out and polish the case mouth but read it anyway you want. And that includes mounting and dismounting the case.
Banger ,you have me curious. What kind of Lee trimmer are you using and how do you hold the case to spin it? Could you describe your process a bit better?

http://www.midwayusa.com/product/717...m-case-trimmer

Uses standard shell holders in your press. Just buy the die for the cal you are trimming.

You do NOT spin the case!!!!! The die firmly holds the case. You spin the cutter blades by turning the crank on top. I have 9 of the dies. Fast and efficient. And you get a little arm exercise in the process. I just dedicated a simple $25 extra Lee press for this purpose. Perfect clean trim + double chamfered in just a few turns of the handle. If one is uber-lazy, they even sell a power adaptor for a drill. Why on earth anyone would need that is beyond me. Holding a drill in the air is a pain in the.........ARM. 6 or 8 turns of the big crank know and all is done.

banger

[rbuck351]

Banger
That is really slick. Where do you buy trimmer dies for 25/20, 32/20,358N,350Rem, 7.62x25,7.62x54R,35Rem,300H&H,22H,30Rem?

[Latheman]

Ive been thinking about doing this myself. I have access to a Johnford twelve tool turret cnc lathe and it uses quick change collets. The way I would do it is set a stop in the spindle use a 3/8 collet for 223/5.56 cases chuck pressure 80 psi. Use a RH turn tool to hit the 1.75 oal than set up the deburr tool in a drill collet and deburr. run all the cases one side reset the stop in the chuck than lightly chamfer the military crimps out. I think about doing this every time im trimming hundreds of .223 cases. Total run time about 15 to 20 seconds side 1 and 10 seconds side two. 15 minutes to write the program. I know most people cant do this but thats why I love being a machinist.

[garandsrus]

A Gracey or Giraud trimmer is a much faster way to go than using a lathe. 2-5 seconds per case to trim, chamfer, and debut the case.

[EDG]

Many of the methods suggested will not trim ALL case designs but an engine/tool room lathe can be used to trim almost anything.

Take a look at the case holders used for a Wilson trimmer. They hold a case on the body outside diameter.

Buy the Wilson holder you need or make one yourself.

Tap the case into the case holder.

Use a 1" 5C collet with a stop on the inside threads. You might figure out a way to use a chuck but collets are far better for this work.

Hold the the case holder and case with the head against the collet inside stop to control the length.

Trim the case with your carriage locked to the right length. If you have to cut off an over length case during case forming you can grind your tool to do that too.

Then deburr inside and out

Remove the case holder from the collet and tap the case out. Make sure you do not leave any shavings inside the cases.

[Tazza]

I like the idea, but it does take time.

I was considering making something so i could make .38 super comp cases from standard .38 super cases. The super comp cases have no rim, unlike the .38 super cases that do have a very small rim. A simple punch setup can remove the rim, the issue is with the small rim gone, the groove for the extractor is smaller than it should be. For playing that is fine, but you want 100% reliability for competitions.

Without a current solution, i just suck it up and buy super comp cases when i get low. I always come home with fewer than i went there with

[Kilroy08]

Hardinge DSM 59. Machinable collet that has been bored to grip on the rim. Set up a cutter, OD deburr, and ID chamfer tool in the lever action indexing turret. If you were slick... Collet grips on rim and is also cut with a chamber reamer and a stop set in the collet. Grip on rim, then flip around and grip case while the primer pocket is reamed.

It would be the Cadillac of case trimmers, also way too expensive for the average yeoman.

[rondog]

FWIW, I love my Giraud Trimmer, it's perfect for trimming bottleneck rifle brass to length, deburring, beveling and chamfering all at once. Even does .30 Carbine with a little more effort.

But I'd kill to have a small lathe in good shape! I was a machinist for many years and got real used to having access to lathes and mills. When you don't have that access any more you really realize how valuable they are. I think of things weekly that I could use a lathe for.

[bangerjim]

IMNSHO....

I use machinable hard brass 5C collets all the time. Not that expensive, but I feel an overkill for the simple process of trimming a case. There are way too many good and viable case trimmers out there to mess with a clumsy and time-consuming lathe set-up. (And I have many decades of expereince with lathe and mill set-ups, usages, and machining techniques).

And why worry about the primer pocket at all? Reaming it will only lead to potential ill-fitting primers in a short time. I have a set of hand pocket cleaner/reamers and rarely ever use them. I don't concern myself with a little black in the primer pocket. Heck, I only clean my brass ever 4 or 5 reloads anyway. I have never found clean & shiny brass brings any additional accuracy to actual shooting.

Just my observations.

[bangerjim]

FWIW, I love my Giraud Trimmer, it's perfect for trimming bottleneck rifle brass to length, deburring, beveling and chamfering all at once. Even does .30 Carbine with a little more effort.

But I'd kill to have a small lathe in good shape! I was a machinist for many years and got real used to having access to lathes and mills. When you don't have that access any more you really realize how valuable they are. I think of things weekly that I could use a lathe for.

You should be able to find a good lathe on Craig's list in a big area like Denver. I would be lost without my 5 metal lathes, 3 wood lathes, and 2 milling machines! If I did not have any, I would go without food to afford one.

[EDG]

A lot of the purpose built trimmers will not cut off a case that was formed from a case .250 longer - that is unless you like generating a rat's nest of shavings for each case. A part off blade hand ground with an angle will easily cut off those long necks and trim in the same motion.
I read a lot of comments about the time burned so that must come from commercial loaders. If you comment you should provide some context because most of us are shooters not ammo manufacturers. The time it takes to load 500 rounds spread over a month is not very consequential.

Another thing that helps is to measure the length of your chamber and record that number.
Then DON'T TRIM until the case get close to the chamber length. Some military rifle chambers are 1mm that is .03937 longer than the trim to lengths in the manuals. You are kidding yourself if you think trimming a case .040 shorter than the chamber means much.
If your case necks get uneven trim the longer uneven cases.

[EDG]

Can you trim every case on the planet with your lee tool? Of course not.
But you can trim most with a 13" lathe. One of the little Hardinge 2nd op machines is very fast and you can do almost anything with them a lot faster than an engine lathe.


You can even make low pressure cases, lube sizer dies, nose punches, - check it out.

With my press-held Lee trimmer, I can trim AND chamfer (inside and out) a case in 5-8 seconds.....lots faster than any lathe set-up.

At 20 seconds to ONLY trim, that is almost 3 hours to trim 500 cases! And you still have to chamfer them.

My philosophy has always been: use the correct tool and for the purpose it was designed for.
Guess that is why I have ever tool made by man.....and many of my own design.

But do whatever floats your boat.

banger

[smokeywolf]

I use a Wilson trimmer that I motorized.

For brass that requires not just trimming, but shortening, like making 45-60 from 45-70 cases I use the lathe.

[bangerjim]

Can you trim every case on the planet with your lee tool? Of course not.
But you can trim most with a 13" lathe. One of the little Hardinge 2nd op machines is very fast and you can do almost anything with them a lot faster than an engine lathe.


You can even make low pressure cases, lube sizer dies, nose punches, - check it out.

Well, I personally do NOT reload every case on the planet. Only normal standard calibers. Not that other stuff some mention on here.

If one loads those cals, then have at it with a lathe device. I will stick with my fast & efficient Lee product. And spend my lathe & mill time making scientific and antique instrument and clock reproductions & repairs.

banger

[Whiterabbit]

I've noticed a few references to people using laths for case trimming.
I'd like to know, what kind of chucking and tooling are you using or have found best ?

Any info and ideas appreciated, TIA.

Cheers, YV

Howdy YV,

I do 400 cases in 15 minutes on a lathe (personal best). That's trim, deburr, and chamfer.

Here's the caveat: I'm not making big cuts. No .1" reductions. Just normal trimming-once-fired-brass kind of trimming. Not "forming". That said, 400 in 15 min is not hard with my setup.

Here's how I do it:

#1: use LEE case trimmer plus piloted bits.
#2: set your cut length by trimming the pin if needed. For max speed you need to use a primer as the datum. I will be intentionally vague there. But you can use the standard twist chuck for the cases and probably get 150-250 cases done in 20 minutes or so.
#3: you put the CUTTER in your 3 jaw scroll chuck.
#4: you set up 3 bins in front of the lathe. One for untrimmed, one for trimmed, and one for cases you tried to trim but no trimming happened (aka no need to chamfer and deburr this bin)

The caseholder you will have to screw into a ball (like a muzzleloader shortstarter) or similar. If you don't need the lee chuck for datum, then you can just hold onto the case itself, like using a WFT chucked into the lathe.

you apply the case to the cutter by hand. While the right hand pushes the case into the cutter, the left hand grabs another untrimmed case. When right hand falls to drop the case into the trimmed bin, left hand meets the right for the case changeover.

Max time is spent applying brass to the cutter. It's very, very fast when setup right.

When finished, take the cutter out and put the debur in the lathe chuck and repeat the process, holding the brass by hand. 2x for debur and chamfer. Fast.

[douglasskid]

That made me head to the lathe to try.
THANKS