case trimmer

I'm getting ready for a reloading party...
I don't own a case trimmer. I'm thinking use my lathe. Build a "U"
shape trough just the size of a cartridge to attach to the aloris tool holder. Set stop on lathe carriage with a cutter in the spindle. Drop cartridge brass in, move carriage to stop, you're done. repeat. I'll need away to stop the brass from spinning that's quick, I'm thinking one of those over center toggle clamps.
Is this a good idea? Got a better one? I'm way to cheap to buy a special machine.
Karl
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Karl Townsend wrote:

Do you really *need* to trim the cases? I've never trimmed my cases and never had an issue. Granted I haven't reloaded a huge amount, but it seemed to me that case trimming was only for the competitive folks.
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Yes, cases need to be trimmed. On the high-pressure varmint rifle cases sometimes every time, the brass grows that much. Necks may need to be turned, also, for thickness. Failure to trim will run pressures up, with top loads maybe popping primers. With most pistol cases, probably not a whole lot of trimming needed other than an initial one for revolver cases, to get a uniform roll crimp. If you're making brass for oddball calibers from other more readily available calibers, you definitely need a trimmer.
As far as the O.P.'s question, you can get a Lee trimmer set for the cartridge and turn the case lock-base however you want, the cutter has a pilot that sets things to length. That's probably the cheapest method, you can use a power screwdriver, an electric drill or wear your fingers out. A lathe would be a cumbersome method. Forster used to sell a trimmer base to be used with a mill or drill press, just had a toggle clamp for their trimmer collets and a cutter head that took the case pilots. There are two other commonly available trimmers that I consider to be properly engineered, one is the Wilson unit, that uses a ground and hardened sleeve for each caliber, the case head rests against a solid support so it's not only coaxial with the cutter, every case is supported the same way. It's a slow but accurate trimmer. I use a Lyman trimmer, the case holder pulls the case against a solid base, one holder does all types and sizes of cases, nothing extra to buy there. The cutter has a very finely adjustable stop and it doesn't move once locked. You just need a pilot for each bullet size, not each caliber of case. Comes with 9 or so, easy to make new ones when needed on a lathe. Can be powered by hand, a drill or an electric screwdriver, for big spenders, they make a powered version. The other brands use collets to hold the case heads, so no real guarantee that all cases will be the same exact length, the collets move back and forth each time you tighten and release, You also need a number of collets to cover all case heads and will still end up with some oddballs not being trimmable.
Stan
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    [ ... ]

    The one which I've had for decades has step collets which position by the front edge against the housing, and the clamp pushes over the taper on the back of the front, so the depth is constant.
    I forget the brand, and I'm not going downstairs to check now (it is already after midnight), but for those who might recognize a description, it has a gold anodized aluminum frame, blackened steel parts for the collet holder at one end and the cutter bearing at the other end, a ground and hardened steel shaft which slides in the headstock bearing, and the end of which is the cutter flutes to surround the pilot. A collar slides on the shaft and clamps close to the proper depth, and then a setscrew is adjusted to bear against the outer end of the headstock and locked with a another setscrew to set the length. There is a crank with a nicely bearinged handle to press on while you crank with the left hand. The collet is closed by a T-handle in the right hand. There are three sizes of step collets, which cover all sizes that I have had to fit. I don't know whether there was a forth collet which I've lost or not. :-)

    The range of the collets above covers everything that I use. To be honest, I've never checked the fit on a .50 caliber machine gun round. :-) Might have problems with a large shotgun shell too, but they are not trimmed anyway -- or are self trimming over time. :-)
    Enjoy,         DoN.
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    A Forster. I was just downstairs.
    [ ... ]

    I'm now *sure* that it would not handle a .50 BMG cartridge. I'm not sure about the big game cartridges. But I suspect that they are not reloaded that often. :-)
    Enjoy,         DoN.
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DoN. Nichols wrote:

Well maybe not for many but I reload mine. WAY WAY to expensive to shoot a lot if you don't.
On the rounds I intend to use for long range work they get a LOT more work as well.
Brass gets inspected for case bulges, splits, cracks, odd deformations, primer pocket and head condition. Then tossed in the bowl and cleaned. Out of there to the bench. They get inspected again for any cleaning media or uncovered damage. Then they get trimmed, de-burred and chamfered along with case mouth wall thickness check. IF they are ones that I have fired before I don't resize them unless there is a problem. Then they get primed all from the same lot, powder all from the same lot and every 5 rounds the powder gets checked for weight. Bullets all get weighed and set into groups by weight. Load up the bullet then into the concentricity tester. This lets me check that each round has the bullet seated the same way and that the tip is centered and everything is OK. If the round checks out I apply a touch of sealer around the bullet and primer (basically melted candle wax in different colors depending on bullet weight) It sounds like a lot of work BUT when you get into a match where the difference between winning and placing can be measured in the thickness of a playing card you tend to get REALLY careful.
Now for plinking rounds for the AR I will just clean the brass, check it for problems, toss it in the hopper and fill the primer tray, powder hopper and bullet tube and start pulling the handle. I built a scale attachment that drops each finished round onto a modified electronic scale that I set to zero with a sample round. Light or heavy rounds trip a red LED and a solenoid that locks the lever so I check the round.
--
Steve W.

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Pete C. wrote:

I was never "competitive" but did like to pot 'chucks out to about 350-400 yds ... and that means fairly hot loads , which can cause the brass to flow towards the neck . If your cases are staying uniformly within spec , don't worry about it . If they are starting to crowd the limit , trim 'em all to the short spec . While you're in a machining mood , check neck thickness and turn them <there are a couple of outside neck-turning tools out there> all to a uniform thickness .
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    If you reload a lot, and are using high-powered cartridges, the cases stretch, and eventually get so long that the end of the case wedges in the chamber gripping the bullet tighter, and increasing the pressure.
    It is a good idea to measure the length, and trim as needed. I'm not sure whether a .357 magnum would grow enough to be a problem, but I do find that the .22 Remington Jet (a bottlenecked case made from the .357 Magnum) do grow enough to need trimming from time to time.
    Probably a .38 special would never need trimming, unless you were loading it so hot that it was threatening to blow up the gun every time you fired it
    And I would certainly check high power varmint cartridges each re-loading -- if I shot those.
    I bought a case trimer decades ago, and it has a set of stepped collets to hold the bases of various cartridges, and the cutter is sort of like a piloted counterbore with a crank. You *do* need a pilot which fits the resized case (trim after resizing) to keep the mouth of the case from walking.
    If you can get a big piloted counterbore for the spindle, and some similar kind of collet for the toolpost (or put the collet in the spindle and the counterbore in the toolpost). For this, you either want a depth stop on the collet, or to take a machinable collet and machine a step bottomed fit for the case base. In my case, I would to it the latter way, because I have a lever-style collet drawbar on my lathe, so it would be a lot quicker to change cartridges.
    Enjoy,         DoN.
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"DoN. Nichols" wrote:

My reloading so far has been 9mm and 7mm Rem Mag. I never suggested not checking the case length though and I do do that on at least a few samples from each batch of brass to reload (all used the same number of times). I haven't found any that have gone out of spec, but I haven't pushed the 7mm brass more than about 4 reloads since I didn't really want to find out the limit of how far they can go before they have issues.
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wrote:

I have a counterbore with a removable pilot. You could use the same counterbore and turn up custom pilots for each caliber. As a matter of fact, I think that's how my old Forster trimmer is set up. Maybe I'll go look while I'm waiting for the chiles and garlic to cool.
Yup, just checked.
Pete Keillor
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On Sat, 03 Mar 2012 08:51:15 -0600, Pete Keillor

So you use chiles in your reloading for "hot loads", Pete? Interesting...
-- It is characteristic of all deep human problems that they are not to be approached without some humor and some bewilderment. -- Freeman Dyson
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On Sat, 03 Mar 2012 09:27:47 -0800, Larry Jaques

Well it is Texas....
No, chili puree => chili gravy => cheese enchiladas from Robb Walsh's Tex-Mex Cookbook. We'll see if it's worth the bother. My handicapped son is a cheese enchilada lover.
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On Sat, 03 Mar 2012 11:40:57 -0600, Pete Keillor

Say no more.

Aw, his taste is all in his mouth. Everyone knows that chicken enchos are the best, followed by string beef enchos.
-- It is characteristic of all deep human problems that they are not to be approached without some humor and some bewilderment. -- Freeman Dyson
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    [ ... ]

    [ ... ]

    [ ... ]

    Just checked mine, too. It is a Forster. Three stepped collets for all the reasonable sizes of cartridges. But the piloted counterbore is also the shaft -- all the way back to the crank.
    I did mis-remember which way around I used it. Crank to the right, collet tailstock to the left.
    Enjoy,         DoN.
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Straight wall pistol cases that headspace on the rim can be fairly forgiving. "Rimless" cases like 45 ACP that headspace on the mouth should be trimmed to a consistent length for best accuracy.
Bottleneck rifle cases should be trimmmed occasionally, depending on the loads & rifle. Mild loads can go a lot longer between trimmings. They should pretty much always be trimmed after the first firing.
I'm in the midst of trimming 3000 once fired .223/5.56 cases. Fortunately, I invested in a Giraud trimmer, which takes about 6 seconds a case. The downside is that it trims relative to the shoulder, so the length will vary if your sizing process isn't consistent.
Doug White
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Make a custom counterbore pilot?
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wrote:

Kind of depends on what cartridge you are reloading. My thought would be to make a die that would let any excess length stick out, and then use a file to take off the excess. Depending on the cartridge , it might be easy to make a die that is good enough. For a pistol cartridge just a hole thru a piece of stock that is the right thickness. For rifle cartidges might have to grind a drill to the shoulder angle.
Dan
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Greetings Karl, If I had to trim a bunch of cases I'd do it in the mill. Using a V block and a toggle clamp would probably work well. If you mount the toggle clamp at an angle such that it moves toward the primer end when clamping then the case would be pulled tight against the mill table and the lengths would repeat closely. I have mounted on my Bridgeport a switch that is controled by an adjustable screw that mounts in the quill stop. I use this switch to control a solenoid operated air valve. I have several air clamps that I've cobbled up from air cylinders and the like. When the quill is raised the switch turns on the solenoid which in turn opens the air clamp. If you have enough cases to trim you could save a lot of time. I'll bet a cycle time, part to part, of less than 7 seconds, would be esay to attain. I could post pictures of the switch setup and a clamp or too if anybody is interested. Eric
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I generally use an air-actuated vise in a cnc mill for that kind of thing.
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PrecisionmachinisT wrote:

One of those air operated 5C collet closers periodically seen in the ENCO flyers perhaps?
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