My 'new' case trimmer...


May 17, 2010, 09:42 PM
So I bought some 'antique' reloading dies from a popular auction site the other day. When the box arrived, it was heavier than what I thought four sets of dies should be, but when I opened it it had a note inside saying 'Hope you can use the extra stuff.' Included were four die sets, from Pacific Reloading Die Co. of Palo Alto, Ca., a newer (I think) RCBS primer tool, which I'm still trying to figure out how to use (no manuals included in any of this stuff), and this - a Grigsby Engineering Case Trimmer:
After cleaning up some of the 'patina', it looks as if it will work just fine. In fact, it seems like it may be a bit over engineered - there seems to be a set screw on just about everything. The collet is what has me baffled - it seems to be 'stepped' inside, like it may be universal, or fitting numerous cases.

I'm also curious about the cutting head, and if it's possible to resharpen it, as it is one piece with the shaft, and not replaceable. Anyone have ideas on this, or know of a source for parts?

ETA: Looking online at the Forster trimmers, I'm now wondering if I can replace some of the parts on this with Forster parts - namely the cutting head + shaft...?

ETA: Well - it still trims brass just fine. I tried it out today on an old 30-06 case. I called around to the few remaining machine shops, and stopped by two of them and showed them the trimmer. Both guys said the same thing - if 'that piece there (referring to the pilot shaft at the business end of the cutting shaft) could come out, it'd be easy to sharpen it.' I even went as far as to call Forster, and ask them about their resharpening service for their trimmer shafts. Because the outside diameter of this one is .497, and theirs are .490, and .552, they said they don't have anything to hold it in while it's being sharpened. They did however politely offer to add me to their catalog mailer list. Both of the machine shops recommended I use a small file when it comes time to sharpen it. Sooo... I guess I'll make this thing work for me, and when the time comes, do my best with a single cut file to resharpen it. I'm still damn happy with it - it was free, it's an old piece of machinery from a bygone era (one of my favorite things), and it still works - I suppose a testament to the tool makers from long ago. I was saddened to find out however, that most of the machine shops in my area have gone the way of the Dodo. I guess instead of fixing anything anymore, people just toss stuff out, and buy new....



If you enjoyed reading about "My 'new' case trimmer..." here in archive, you'll LOVE our community. Come join today for the full version!
May 17, 2010, 10:39 PM
the collet looks like it has the same design as the rcbs trim pro. which has collets which can hold several case heads. the cutter may be to hard to sharpen with a file. it would not take to much to modify it to take the rcbs 10 dollar cutting heads. it looks to be good quality.

May 17, 2010, 10:55 PM
SCORE! Congrats!

And as a last resort I'm positive you can take your cutter to a "tool grinder" shop to have the blades sharpened.


May 19, 2010, 07:37 PM
Just found a source for a new Brown & Sharpe style collet for it - my brother in law in Ca. has been a machinist for all of my life! He's checking to see if he has the right tool to make a new cutter shaft + head combo...

May 19, 2010, 07:57 PM
The pilot should either unscrew or have a set screw on the shaft to hold it in place.

Many small machine shops made various specialty reloading tools and dies in the 50s -60s. Much of what I've seen of it was well designed and well made but most of them couldn't get a big enough toe hold in the market to survive.

Stepped collets (Brown and Sharpe type) are common shell holders for trimmers.

May 19, 2010, 09:35 PM
Is the collet bad? I could understand the cutter being dull. Mine almost got messed up by water from a storm which blew the top off my reloading shed. I sharpened my cutter with a flat fine diamond hone from a knife sharping kit. I was very careful and took my time as not to change the angles of the cutter. Works as good as new!

Jimmy K

May 19, 2010, 11:12 PM
Ranger - The pilot isn't removable. It was pressed in place, hence the sharpening problem. I think I have a replacement cutter shaft lined up though!

Jimmy - The collet isn't bad - I'm just trying to line up replacement parts beforehand, rather than after something goes wrong. There is indeed, a Murphy in my family tree.

The good side to all of this is, my brother-in-law is a machinist for a japanese automakers performance F1 division. After showing him pictures tonight, he's fairly confident he can have the two parts CNC'd for me in about 9 minutes... I'm sure it's going to cost me somewhere else though... Still...Not bad for a free case trimmer, which still works pretty dang good for my limited knowledge.


ETA: That had to be one hell of a storm!

May 20, 2010, 06:07 PM
Small Tornado... got my shed, My dad's tobacco barn, a wire fence, neighbor's tractor shelter and who know what else along it's path. Big, tall pines all over my yard, not a single one on my house! Scary thing is my brother, Dad and I watched it do all the damage. Murphy could have been the storm's name!

Jimmy K

May 21, 2010, 12:59 AM
Jim, could you post the dimensions of the collet attachment you showed me?

May 21, 2010, 01:17 AM
but when I opened it it had a note inside saying 'Hope you can use the extra stuff.'
Nice. Bet you haven't been told that many times.

The patina would be the only reason I would suspect you'd have to actually sharpen the cutting edges.

I'd be worrying more about finding a way to put a motor on that crank handle. Which you could do, with a nice vertical jig that holds the rig in a drill press for you....but I digress. Good luck with the free stuff. Nice problem to have.

May 21, 2010, 08:10 AM
It is a piece of cold roll steel .500 in diameter with the small/large primer pilot turned on it. I cut the pilot slightly smaller than the nominal primer size to allow the case to fit on but not move much. The pilot is shorter than the depth of nominal pocket to avoid the bottom of the primer pocket setting the OAL of the case. The length of the case is determined by the bottom(face) of the cartridge to the edge of the trimmer cutter. Really a min-lathe with two centers, if you can picture that. Fingers provide the holding power to keep the case from turning. That is not hard if you don't put to much pressure on the cutter. If you put too much pressure on the cutter, you can't hold the case. A sharp cutter helps.

Here are the exact dimensions I used:

Small primer pilot: .170 Diameter - .085 length

Large primer pilot: .205 Diameter - .120 length

The over all length of the whole pilot itself: .750 length - .500 Diameter, it will fit in the same step as a 30/06 rim in the collet.

Jimmy K

May 21, 2010, 04:23 PM


May 21, 2010, 05:59 PM
Like this (

I copied Jim's idea. The royalty check is in the mail. ;)

If you enjoyed reading about "My 'new' case trimmer..." here in archive, you'll LOVE our community. Come join today for the full version!