Case length trimming-procedure improved

[oldman10mm]

When I started reloading in the 70s',it wasn't long before 'there has to be a better way'.
ALL cases get trimmed,rifle and handgun. Most say there's no purpose/reason to trim handgun brass. After I started trimming to attain a consistent crimp,all of a sudden chronographed velocities shrank in variance.
Turning the hand crank manually didn't last long. I worked in a lab that had machining facilities and I made a shaft for powering. They're available now,back then they weren't.

That worked fine but had to work on trim length adjustment next. Had/got a bunch of washers/spacers for the 9/16" shaft diameter of the trimmer. Had a large enough variety to accommodate anything. Once the trimmer was set for the shortest case I reload(which was 9mm back then),remove the shaft from the housing and insert the appropriate spacer(s) to accommodate a longer case.

Worked fine for many years. But always room for improvement.
So,a 'Master Case length Gage'.
Fabbed up a 9mm 'master'

Made it to SAAMI minimum case length .744"(I'll get to the reason for this further down). Put the master in the trimmer case holder,removed the trimmer pilot,put the cutter head against the 'master' and locked the adjustment collar down there. Removed the master,inserted the pilot back in,inserted a 9mm case and trimmed it. It came out .744,no more adjusting or spacers.
Ordered some steel tubing to start making other 'master gages'.

And then made these

Everything has been working FINE.
The reason for using SAAMI minimum length is if I want,let's say,.005" longer than SAAMI minimum length,all I have to do is put a .005" automotive feeler gage between the master and the cutter head. Impossible to go shorter but easy to make longer.

 

[rwsmith]

I love ingenuity....

That is a neat set-up.

 

[C Broad Arrow]

Interesting set up. How did you cut the steel tubing to be precise measurements?

 

[Nemo288]

Very cool set of adaptations.
I have that old grey Lyman.
Think I got it used in the 80's sometime.
Unfortunately it doesn't cut square any more.
It may never have, I just started to care more.
I think the main bushing is shot.
Looking to get something newer like the Wilson or CH4D.
I only trim a box or 2 a year so it's hard to justify the expense.
Once is enough for cylindrical cases.

 

[oldman10mm]

In reference to post#3,how was I able to cut them precisely.
Those should have been fabricated on a lathe but I don't have one. Cut(as squarely as possible) them in a vise with a hacksaw to about 1/16" of the dimension I needed. Then still with in the vise,hand filed (as squarely as possible) each end until I got .001-.005" over the dimension I needed. My basement drill press has a 1/2" chuck capacity so I 'chucked' them up in the drill press and ran them down into emery cloth/sandpaper to truly square the ends. Once both ends were 'square',I worked one end down(in the drill press) into the emery cloth until the dimension was reached. It was time consuming,but I'm retired and it was winter with snow outside so I had the time to do it.

 

[H Richard]

I've used a cordless drill to power my RCBS for quite a few years. I just took a bolt with the same thread as the one securing the handle, and turned the head off. Chuck my drill on that and use a pre trimmed case to set the stop. Don't see any reason other measuring devices, just have a set of cases set aside as the measure.

 

[gregintenn]

I chuck the old Lee shell holder in a hand drill.

 

[da gimp]

nice set up oldman10...

 

[Just another 22 shooter]

For trimming rifle cases, I've been using a Forster trimmer with a drill press for more years than I can remember...........MUCH easier on the wrists and hands than a hand crank. I don't trim pistol cases.

 

[USSR]

Ya got WAY too much time on your hands.

Don

 

[Cdog]

Impressive work.

I'm fully automated/powered on case trimming. RCBS 3 way cutter for most common rifle cartridges.

If I felt the need to trim pistol cartridge brass, I'd likely get over it...