Sizer die set-up help

T

Tom Howell

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I have been using a Partner press and a Cartenson FL Die for several years with no problems. I purchased a set of shims last year as I have two rifles with slightly different headspace requirements and have used them with no problem. I bought myself a combo press and decided to set up my die this afternoon and here-in lies the problem. The same shell holder and die used in the Partner will oversize the case and push the neck back by probably at least 0.007 if not set up proberly. With the Combo press, with the same shellholder tight up against the ram before the ram reaches top stroke, I cannot push the shoulder back enough to measure and the case is still slightly tighter than I would like when closing the bolt. What causes this and what is the easiest remedy. I am not a machinist so if I need a thinner shellholder, where would I get one and more important, why would I need it when the same combination of shellholder and die work so good with the Partner? Thanks for your help. Tom:confused:
 
I don't have any experience with either of the presses you mention but the only thing that can cause the problem you describe is if the case doesn't enter the die the same amount even though the set up seems to be the same as in the old press.

It would seem that something in your press set up isn't working right in regards to allowing for the press stretch.

I used to use a big old Rockchucker style press, plenty of power and rigidity. I used Redding "competition" shellholder with the shellholder bottomed out hard on the bottom of the die. You swap incrementally taller shellholders over to set the shoulder bump. That worked fine until I got a Sinclair custom press with a C frame design.

The smaller Sinclair wasn't rigid enough to work to my liking with the shell holder hard on the die so I bought a set of die shims and set up the shoulder bump that way. The press frame stretches with the force needed to push the case in the die but there is no additional force from the shell holder bottoming out on the die.

When using the shims the shell holder should not touch the die otherwise swapping shims will alter the force of the shellholder on the die and alter the press stretch and thus also alter the shoulder bump. Alternatively, depsning on the set up, swapping shims will not alter the case sizing at all because all the change does is alter the press stretch.

Bryce
 
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Sizer die set-up

Tom Howell: yes, I had the same problem years ago with one of my .223 rifles: could not set the shoulder back far enough. Had the die adjusted down as far/tight as possible on the shellholder. I suspect your problem was created with the new press: dimensions are all different on all presses. Easiest way to go is get a set of shellholders that have different height dimensions, or take your shellholder ( to a machinest?) and have him surface grind .008" to .010" off the top of the shellholder. Sinclair Int'l. has the shellholder set. Hope this helps.:)
 
I figured that I might need a different shellholder but isn't the relationship between the shellholder and the die constant except for the possible flex? I am talking a world of difference here as I know I have mistakenly set the shoulder back way too far in the past before I bought the shim set. Tom

Still confused:confused:
 
If the die and the shellholder are the same as were used before (it is the same shellholder ????) then the press used shouldn't matter once it is set up right.

The Redding shell holders that Sinclair sell will not allow you to size a case shorter than the standard height shellholder, they are all taller than normal so the case is sized longer in 2 thou increments. They use the standard shellholder as a zero reading and go in +2 thou steps to +10 thou maximum.
 
Tom Howell said:
The same shell holder and die used in the Partner will oversize the case and push the neck back by probably at least 0.007 if not set up proberly. With the Combo press, with the same shellholder tight up against the ram before the ram reaches top stroke, I cannot push the shoulder back enough . . .
Click to expand...
maybe this is just terminological -- It sounds like if the shellholder hits the die (not ram, but die) in the Partner setup, you resize .007 too much. So, you've backed off the locking ring on the die, so the shellholder no longer hits the die. Presumably, you've reset this for use in the other press, but . . .

The words you use with the combo are "shellholder tight up against the ram before the ram reaches top stroke" did you mean "tight up against the die"? That would be a different situation.
 
Tom,

Is it the same shellholder ?

If yes then the only issue logically can be in the stretch of the press frame or linkages when sizing.

Get down at eye level and look for the shell holder to be further away when sizing a case than when there is no case in the die. The difference can be a lot and many people underestimate the effect of press stretch, especially one that isn't a big heavy O frame design.
 
Charlse, you are correct in that with the Partner press the shellholder does not quite touch the die for a setback of a measured .001 give or take. With the shellholder firmly bottomed out on the combo, I still do not set the shoulder back at all. Tom
 
BJS6, sounds to me like stretch is the only variable as the shellholder and die are constant. I best order a set of shellholders from Sinclair. Thanks. Tom
 
sizing die, again

Tom Howell: Good point was made previously about the thickness of the shellholders. If the Sinclair/RCBS set only gets "thicker" from standard, then they would not help. Call Sinclair and put the problem/question to them before making an $$$ purchase. They are very helpful with questions. It still sounds to me like you need a thinner shellholder, as I did, if you cannot set the shoulder back far enough. I've always used the "StoneyPoint"/ now Hornady headspace gage, take a dimension from a case fired in my chamber(s), then adjust the die to get the same measurement or a max. of .002" less. I like a little resistance when closing the bolt.:)
 
Hold fire on the shellholders Tom, they will only make the problem worse !! They will make the case enter the die even less and you will never bump the shoulder.

In the partner press as you indicate the shell holder just about hits the die when set up for a 1 thou shoulder bump. All good.

When you have put the same shell holder and die in the new press there is more stretch in the press and the same set up as in the partner press will not size the case the right amount.

That doesn't alter the fact that if the shellholder hits the bottom of the die the case shoulder will be forced back more than you need. The die and shellholder will work and the press they are in is irrelevant.

To allow for the extra stretch of the press frame you will need to wind the die further into the press than it is now but when sizing a case the press will stretch and the die will raise up relative to the shellholder and when set right will end up in the same relative place as it was in the partner.



Try this:

wind the die in so it just bumps the shellholder with the ram all the way up, just kisses it lightly. Now lube and size a case and get down at eye level and have a look at what happens, the shell holder will no longer reach the die. That gap is the stretch that you need to allow for.

Put no shim under the die collar and wind the die down until the shell holder bumps hard on the shell holder and still hits the shell holder when you size a case, just keep winding it in, you won't hurt anything. Now when the die is in far enough so that the shell holder stays on the die you can add shims to lift the die back up some until you reduce the shoulder bump as needed. At the right setting with shims the shell holder will just miss the die at the right bump just like it did in the partner press. Depening on haw far in you wind the die you might need a decent stack of shims to get the bump right. If you needed say 15 thou of shims you could simply wind the lock ring in by 10 thou worth and fine tune the shims again to end up with something around 5 thou.

It'd probably be easier to set up if the shellholder was skimmed by asy 10 - 15 thou so it never hits the die but that isn't vital.

Bryce
 
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When you have put the same shell holder and die in the new press there is more stretch in the press and the same set up as in the partner press will not size the case the right amount.
Click to expand...
This makes no sense to me. If the same shellholder is solidly against the die, it doesn't mater how much stretch is in the press.

What I suspect is that when actually sizing a case, the shellholder is not hitting the die with the "combo." Should be easy to check with a feeler gauge or shim stock, since there seems to be about .008 extra (based on the Partner setup.)
 
We are saying the same thing Charles.

What I meant by the "same set up" was the same relative position of shell holder to die BEFORE the case is actually being sized, the same starting point if you like. The same as Tom used in the old press.

In that case the change in press stretch will alter the ACTUAL or EFFECTIVE set up under load when the case is being sized.

All that is happening is the press is stretching differently to the old one and a new no load set up is needed to achieve the same set up under sizing load.

It is clouded slightly by the fact that it sounds like at the proper set up the shell holder is in contact with the die with with no case in the die but will in fact come away from shell holder contact when sizing the case properly. It would be easier to see what is happening if the case wasn't on the shell holder at all or it needed to be hard on the shell holder under sizing load to size correctly.

Bryce
 
When I screw the die down farther on the Combo press I just bottom out the stroke sooner and don't gain anything on the shoulder push. I am still puzzled as to how this can be possible as it appears that I have compensated for all of the flex without gaining anything. I am sure a thinner shellholder will fix the problem but why is still beyond my thick skull. Tom
 
Maybe tomorrow I will try the other rifle as there is about .003 difference between them. I have to use a thicker shim with it so if it works then I will at least know that I am close. I ate a pretty good lunch today so I think I was pushing pretty hard! :) I was clamped to my metal bench that weighs a bunch. I thought about that but no matter what I tried I was never able to push the necks back. My other press is bolted next to this one so I would take the die out and after fine tuning the adjustment ring, I was able to size all of the brass to between .0005 and .001 as best as I could measure. Just when I think I know a little bit about reloading after 40 years I seem to always find somethiing new to bite me in the bottom side! Thanks for all of the help. Tom
 
Ru

pushing the handle over center.Try setting it up to do the job before the top of the stroke.Just a thought.Good luck Jim
 
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