If you happen to have a Unimat SL or DB200 mini-lathe around the house, and you need something to trim your cartridges to the proper length, you're in luck. If you don't have a mini-lathe lying around, it's not worth the cost of buying one just for trimming cases. I just happened to have one that my dad gave to me, so I decided to give it a try, and it works great, with just a couple minor mods. The first thing you need to do is buy a case trimmer with a diameter of 1/2 inches.
I just happened to have a Lee Precision 90275 hand trimmer lying around that I just bought from Amazon. I had to cut the ball off to free the cutter head and shaft. That pretty much nixed any chance of a return. The important thing is that the diameter of the cutter head is as close to 1/2 inch as possible.
I just happened to have a Lee Precision 90275 hand trimmer lying around that I just bought from Amazon. I had to cut the ball off to free the cutter head and shaft. That pretty much nixed any chance of a return. The important thing is that the diameter of the cutter head is as close to 1/2 inch as possible.
Unfortunately, the Unimat's tailstock hole diameter is 0.47, and the Lee cutter's diameter is just under 0.50 (0.495), measured with my $50 digital caliper from Home Depot. After several tries at making the cutting head fit, I resigned myself to the fact that I would have to bore about 3/4 of an inch of the original tailstock, using a half-inch drill bit. The tailstock hole is slotted, and even after boring, the cutter wouldn't just slide in without a little help (spreading the slot using a flat blade screwdriver).
If you limit the depth of your bore to just what is needed to fully contain the Lee cutter head, you won't ruin the original tailstock. The lathe tailstock centering bolt will still fit and work. My attempt to reduce the cutter shaft diameter is shown in the far left photo below. I took the cutter out to my work shed and used various metal files with the cutter chucked up in a drill press, to no avail. When Lee says it's hardened, they mean it's HARDENED.
If you limit the depth of your bore to just what is needed to fully contain the Lee cutter head, you won't ruin the original tailstock. The lathe tailstock centering bolt will still fit and work. My attempt to reduce the cutter shaft diameter is shown in the far left photo below. I took the cutter out to my work shed and used various metal files with the cutter chucked up in a drill press, to no avail. When Lee says it's hardened, they mean it's HARDENED.
Below: Using the Unimat to trim 30-06 cases. If you insert each case all the way to the stop in the chuck, and use a new case to set the correct case length distance, you will get a precision trimmed case every time. I moved the tool rest all the way to the right until it contacted the tailstock, to make it easy to reset the length for 30-06 cases.
