Old RCBS trimmer problems

[bigjake]

I have an older RCBS trimmer. Im not sure what model, it dosnt have any identifiable markings. Its made of either cast aluminum or die cast pot metal. It has 3/8"-16 nc threads on the T-handle thing. The problem is; I cant get repeatable dimensions with it. when you put the case in the collet, the more you tighten the collet, the more it draws the case away from the cutter. it has no stopping point. I can get some case lengths kind of close but not close enough. I have an old forester trimmer, when you tighten the collet, it has a definite stopping point.

Does anyone know how to use this old trimmer?

thanks

[EDG]

The original RCBS trimmer had a pull collet system as you described it.
The pull collet stops based on how tight you turn the Tee handle (same as the draw bar on a lathe collet) and the diamter of the case head. A smaller case head will allow the collet to be pulled in deeper.

The later RCBS trimmer does not have that problem. I think the second generation trimmer was a push collet design like the Forster. Then the 3rd generation is the Trim Pro with the spring loaded lever.

I would contact RCBS for the parts to convert you old trimmer to the second generation style or I would get rid of it.

[JimKirk]

Like this one ....here is my solution...





I made these pilots ....they go in the collet and the trimmer becomes a between centers cutter .....makes it much faster with a cordless drill attached to shaft...

Place a case on cutter pilot ...slide brass on collet ....tighten collet good(this makes sure the two pilots are in line with each other .....set cut length ...

Simply place case on the pilot (Small primer or large primer size) ...hold case with fingers(a rubberized glove may help you) ....push the cutter shaft at high speed towards case..... the speed cuts the brass smooth and quick ....

You use the depth stop to set the length ....your brass will come out the same length each time as long as you go until the stop. The brass head face is the controlling point not rim diameters....once the distance is set ....unless the stop moves ...the length from the brass face to cutter will always be correct...

I made these out a 1/2" piece cold roll . ...in a drill press with a file ....

[bigjake]

Thats the one JimKirk! thats a good idea. I have a sm lathe. I will whip a couple of those do-dads out!
It must have took a day to make those. it looks like you made them on a lathe, thats some good filing!

thanks for helpful replies.

EDG, I will call rcbs again. I phoned them about it before. I was nice to the lady. I told her that " I have all RCBS equip., and its all top notch, except that trimmer. I said that I couldnt believe rcbs was capable of making something so useless. I said that I was sorry for being so negative but that needed a trimmer that worked and thought the rcbs was a sure thing regardless of its age"

[Minerat]

They have 3 different collets for this old trimmer. Each one handles 4 different case base sizes. You have to match the shell base with the collet, I do this by placing the case in the collet then on the pilot. I push till the base sets then tighten the collet a quarter turn and trim away. Seems cumbersome but in practice it is pretty fast.

[JimKirk]

Regardless of using correct collet or not ....when the rim diameters vary ... as they do ...the pull type collet are going to give varying lengths ...

With the push type collets ....they "catch" on the front edge of the housing ....the closing taper is pushed forward over the collet ....the collet does not move ... whereas the pull type do move away from the cutter/stop because the closing taper is in the housing ....

I am sure there are other ways to "fix" this problem .... but my solution is the easiest and not only that ....it speeds up the use of the cutter when using a cordless drill ....zero time spent closing a collet...

[44magLeo]

I really like JimKirk's idea. I had a Lyman trimmer that worked like that. Figured out the variations I head/rim size caused variations in trim length.
I then went with the Lee trimmer. It uses a mandrel to control case length. Found most cases were short. I used it case a gauge, when case grew enough to need trimming the cutter trimmed them.
I lost a lot of my old reloading stuff in a move, so I don't have that trimmer any more. I might shop around to see if I can find one for a good price, then build such an adapter for it. Looks easy to make.
Make it with a peg that fits large primers pocket on one end, small pocket on the other.
Good Idea.
Leo

[Hollywood_Goon]

Indexing off the primer pocket will not yield any difference than indexing off the cartridge case base. Primer pockets are simply not uniform in depth. The only way to achieve this is by uniforming the primer pocket with a primer pocket correction tool.

Primer Pocket Correction Tools
https://kmshooting.com/product-categ...et-correction/

[ulav8r]

The primer pilot is for centering the base, it should not bottom in the primer pocket. The base of the cartridge will index on the shoulder of the pilot and give consistent results.

[JimKirk]

The pilots do NOT bottom out in the primer pockets ....they only serve to keep the brass inline with the pilot on the cutter head ....to make sure the cut is square with the head....

The brass face is the index point ....not the bottom of the primer pocket.

The photo may be misleading ....the primer pilot are much shorter than the depth...

[ioon44]

My solution for this trimmer problem was sell it and buy L E Wilson trimmers.

[Walks]

JimKirk, that's a great idea.
Back when I used one, it was simply a matter of a "light touch". Got to where I could trim to a repeatable one thousands off.

For the last 32+ years it's been a Lyman electric or a Forster.

Old RCBS is still sitting under the bench w/ all 4 collets.
Ya just never know when you might need something stashed away.