Lathe case trimmer
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Unless the collet is custom made with a step ground into it to serve as a case head depth stop, you won't get uniform case position each time. That means you will have to be individually measuring and then trimming off the difference calculated. It will be a painfully slow process. Even then, it will only work well on rimless case heads. The others need a step ground into the collet anyway, because a rim or a belt, which are the widest part that the collet will grasp, don't have enough length to straighten out in the collet, so they won't run true without that. Then you need a cutter to trim with that won't pull them loose from that precarious hold on that narrow band of brass, so you'll end up buying the same piloted cutters several of the commercial lathe trimmers use.
Where you might get some mileage out of your lathe would be by chucking the Lee trimmer holder is in it, then using their cutters. About $5 or $6 for each half of the gear. Run the lathe at about 150-200 RPM or so and insert the cutter by hand. Let the lathe engine to the turning part, which spares your fingers.
By the way, I don't know what you are planning to load for, but be aware that cartridges fired below approximately 30,000 psi will shrink rather than grow with use. There is never need to trim .45 ACP, for example, as long as you are using a taper crimp die. For roll crimping lower pressure rounds, you may want to trim cases short just once to get them uniform so the crimps will be uniform. That usually means trimming slightly shorter than normal, so you might find you have to grind a little off the Lee "length gauge" part of their trimmer to get where you want to go with it?
Where you might get some mileage out of your lathe would be by chucking the Lee trimmer holder is in it, then using their cutters. About $5 or $6 for each half of the gear. Run the lathe at about 150-200 RPM or so and insert the cutter by hand. Let the lathe engine to the turning part, which spares your fingers.
By the way, I don't know what you are planning to load for, but be aware that cartridges fired below approximately 30,000 psi will shrink rather than grow with use. There is never need to trim .45 ACP, for example, as long as you are using a taper crimp die. For roll crimping lower pressure rounds, you may want to trim cases short just once to get them uniform so the crimps will be uniform. That usually means trimming slightly shorter than normal, so you might find you have to grind a little off the Lee "length gauge" part of their trimmer to get where you want to go with it?
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I have a good South Bend 9" lathe. I have good, accurate 3C stepped collets.
I trim my cases on a Lyman Universal Case Trimmer, hand cranked.
I trim my cases on a Lyman Universal Case Trimmer, hand cranked.
As of now all I reload is shotshells. When I start reloading metallic it will be rifle, 243, 25-06, 7mm, 270 and maybe 30-06. For now I'm just trying to get educated and determine which loader and tools to purchase. My first will be a lyman book.
Back to the lathe, I can make a stop which comes in from the back of the collet, maybe even make something that can be adjusted easily (threaded). I would use the 3 jaw chuck but the pressue to grip the case may bend it. If the case has a rim, side not even, I got problems. If the three jaw chuck can be used I can machine a groove in the back of the jaws to allow clearance for the rim. The jaws are aluminum and I have extras, however, a groove in the back is not going to cause a problem when used as a lathe.
Thanks
Back to the lathe, I can make a stop which comes in from the back of the collet, maybe even make something that can be adjusted easily (threaded). I would use the 3 jaw chuck but the pressue to grip the case may bend it. If the case has a rim, side not even, I got problems. If the three jaw chuck can be used I can machine a groove in the back of the jaws to allow clearance for the rim. The jaws are aluminum and I have extras, however, a groove in the back is not going to cause a problem when used as a lathe.
Thanks
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I use the setup described by unclenick on my Sherline lathe. Works well for small runs of brass to trim. Large batches I use my drill press with a Forester collet setup. Works like a charm and is very fast with high production rate. Would assume if you have a lathe then you've also got a drill press be it floor or bench model.
The Forester collet unit is bolted to the drill press table, an alignment rod is chucked in the chuck and run into the collet base. The bolt in the base is tighten and rod removed substituting the cutter head. All thats left is adjusting cutting depth setting the quill lock.
Hunting buddy and I trimmed over thousand 223 cases, inside and outside deburred case necks all in less than three hours with this setup.
The Forester collet unit is bolted to the drill press table, an alignment rod is chucked in the chuck and run into the collet base. The bolt in the base is tighten and rod removed substituting the cutter head. All thats left is adjusting cutting depth setting the quill lock.
Hunting buddy and I trimmed over thousand 223 cases, inside and outside deburred case necks all in less than three hours with this setup.
I ran across a guy from NH while shooting at the Wilson Matchs in the late 70s that came up with a unique method of triming cases, it works its fast and its accurate.
Its based on a rod with a cutter that trims and bevels the case at the same time. The rod is the same size diameter wise, as the mouth of the case, the cutter had a V notche that is adjustable via a slot in the rod. An alen head screw tighents the cutter. You run the rod in the case until it bottoms out, then slide the cutter to the proper lenght. You put the rod in a drill press, turn it on, then run the case up until it bottoms out and your done. Just that fast, slide the case over the rod until it bottoms out. You can use a collor over the rod to keep chips from flying around but if you wear safty glassed you can get by without the collor.
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Its based on a rod with a cutter that trims and bevels the case at the same time. The rod is the same size diameter wise, as the mouth of the case, the cutter had a V notche that is adjustable via a slot in the rod. An alen head screw tighents the cutter. You run the rod in the case until it bottoms out, then slide the cutter to the proper lenght. You put the rod in a drill press, turn it on, then run the case up until it bottoms out and your done. Just that fast, slide the case over the rod until it bottoms out. You can use a collor over the rod to keep chips from flying around but if you wear safty glassed you can get by without the collor.
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I too have a Sherline and use Lee trimmer stuff I purchased their "THREE JAW CHUCK" and "CASE SPINNER STUD" ($20/both). Their "CUTTER w/BALL GRIP" ($7). Now all you need is the proper "CASE LENGTH GAUGE" (>$6). (I like that system because it requires NO jerking around. Just screw the CLG you want to use into the Cutter and you're ready to go) I set the crossfeed table so I can rest my right hand on it while holding the cutter ball. I chuck the case into their 3-jaw and hit the switch. The lathe does nearly all the work with just a bit of pressure applied with to keep the cutter removing brass It's easy and I like easy! I've even had them make a goodly number of "custom" versions ... like for my .297-.230 Morris Short that I just got done reloading (.223" heeled 40gr lead bullet with a case loa of 0.574"). I used Buffalo Arms reformed Hornet brass ... so you can see that I've removed a good bit of brass to get to where I wanted to be. Not as fast as the drill press I'd guess, but it works fine for me!
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That looks interesting. Is the interior web depth that consistent? I have to assume it needs to be all one brand, since that dimension varies by manufacturer.I ran across a guy from NH while shooting at the Wilson Matchs in the late 70s that came up with a unique method of triming cases, it works its fast and its accurate.
Its based on a rod with a cutter that trims and bevels the case at the same time. The rod is the same size diameter wise, as the mouth of the case, the cutter had a V notche that is adjustable via a slot in the rod. An alen head screw tighents the cutter. You run the rod in the case until it bottoms out, then slide the cutter to the proper lenght. You put the rod in a drill press, turn it on, then run the case up until it bottoms out and your done. Just that fast, slide the case over the rod until it bottoms out. You can use a collor over the rod to keep chips from flying around but if you wear safty glassed you can get by without the collor.
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My mini lathe works great for trimming cases. You do not necessarily need a collet system to hold cases. The chuck jaws have recesses in them. I found that the cut off base of a 30-30 case will fit in the recess and act as a base to stop a 30-06 case in a uniform position. Loosen the jaws just enough to remove or insert the 06 case and the 30-30 case head stays put. If you form 7.65x53 Mauser cases from 30-06, as I do, you have about .4" of case to trim. The mini lathe makes quick work of it. I have a dial indicator on the tailstock quill and all my cases come out the same length within .001". I also make bullet seating plugs for myself and custom M die plugs.
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I have a Sherline and use a LEE 3-Jaw Chuck and their Case Spinner Stud. I just screw the correct Case Length Gauge into the Cutter With Ball and have at it ... all for just under $30 ... not counting the Case Length Gauge ($5.5And while the case in right there ... inside and outside chamfer and you're ready to go!
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