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Best Lock Rings for a CO-AX

I need some new lock rings for some more dies I picked up to be used in a Co-Ax. I know the old Forster rings were aluminum with a straight slot tightening screw that didn’t serve the purpose very well. I have been using steel Hornady Sure-Loc Rings with a hex screw that has worked well. They are a little thinner than the old Forster rings so they move up and down in press slot more but it never seems to cause any issues.

Anyway, I think I saw that Forster redesigned their lock rings… aluminum with a hex screw.

What type of rings do you guys like in the Co-Ax?

Thanks.
 
I use only Forster in my Co-Ax.
I like the thinner Hornady lock rings for the case holders that go with my Giraud Trimmer.
 
Use the Forster aluminum rings. Unfortunately, they are pricey but if you buy the pack the comes in a dozen, it'll save you a little money.
 
Has anyone checked to see if they are square to the die threads when locked?
Rings can look good but be out of square.

the Sinclair steel lock rings that I use have been square. YMMV.

Another thing that has not been mentioned specifically is the aluminum versus steel issue. I have been using the coax for a long time it gets a lot of use. I feel that steel is your friend....after a lot of sizing strokes I have had problems with the aluminum rings because the aluminum threads either slightly deform and the shape or pitch changes, and/or they deform out of square. Took me a while to figure out the cause of having to re-adjust for bump, or cases that were not sized perfectly square.
 
Bugman
I am not surprised by your finding the deformation of the rings. The original design of lock rings for 7/8-14 dies did not intend them to be load bearing. In this case I am referring to the original Pacific dies designed long before Bonanaza came along. They were originally just a lockable ring that permitted reinstallation of the die to the same setting every time. The die threads took the sizing force. The lock ring took no force.

I do a lot of case forming including swaging of the case heads and I know that the aluminum lock rings with the small #6 screw are not going to withstand that forming pressure. The CoAx press has a lot of mechanical advantage but using the .312 thick aluminum lock rings to take the sizing loads was not a bright idea. The .312 thick ring needs to be machined with significant precision to insure it stays square on the sloppy 7/8-14 die threads. The short ring is only long enough for 4.99 threads but the chamfer of the thread on each side of the ring will remove about 1 thread total leaving only 4 aluminum threads to take the sizing forces. This is probably not a big concern for most users. However when forming cases or swaging case heads I have split several FL dies and I know that using only the lock ring to take the sizing forces would break the lock ring.
Quality steel rings would be better for heavy duty operations especially if they are of the non-split variety like a Redding ring so they cannot break the screw.
For extra heavy duty a different press should be used be cause the lock rings are the weakest part of the design and there are no good work arounds.



the Sinclair steel lock rings that I use have been square. YMMV.

Another thing that has not been mentioned specifically is the aluminum versus steel issue. I have been using the coax for a long time it gets a lot of use. I feel that steel is your friend....after a lot of sizing strokes I have had problems with the aluminum rings because the aluminum threads either slightly deform and the shape or pitch changes, and/or they deform out of square. Took me a while to figure out the cause of having to re-adjust for bump, or cases that were not sized perfectly square.
 
A while back a friend who has a lathe did some truing of lock rings. He chucked up a piece of stock and cut 7/8-14 threads on it, then he clamped lock rings on that thread, and took a light cut off of one face, and then flipped the ring and did the same thing on the other. Lock rings from several manufacturers were found to need some work.l I have always been curious about this detail. Shooters make so much of squareness and concentricity but assume these mass produced parts are straight. There is also the matter of whether the ID of a die is coaxial with its threads. That would take a more elaborate setup to check.
 
A while back a friend who has a lathe did some truing of lock rings. He chucked up a piece of stock and cut 7/8-14 threads on it, then he clamped lock rings on that thread, and took a light cut off of one face, and then flipped the ring and did the same thing on the other. Lock rings from several manufacturers were found to need some work.l I have always been curious about this detail. Shooters make so much of squareness and concentricity but assume these mass produced parts are straight. There is also the matter of whether the ID of a die is coaxial with its threads. That would take a more elaborate setup to check.
I think it's much to do about nothing.
When the case is being pushed in the die as long as the head of the case is being pushed straight . The case should mirror the die . Forster presses not only does the die move but the shell holder floats So you have a better chance of a straight push. . If the locking ring is tight. That's is all that matters.
Larry
 
Use of the lock ring slot in the Coax does not allow the die to tilt in any direction. If it is off it will stay tilted no matter what the marketing BS of Forster claims.
There are 6 degrees of freedom and the Coax only allows 2 to align. The third axis is the Z motion and it is just the vertical travel of the die head. Looking at the die from the front there is no compensation for CCW or Clockwise tilt off of the centerline. Looking at the die from one side you have the same problem. It cannot line up if tilted off axis.


I think it's much to do about nothing.
When the case is being pushed in the die as long as the head of the case is being pushed straight . The case should mirror the die . Forster presses not only does the die move but the shell holder floats So you have a better chance of a straight push. . If the locking ring is tight. That's is all that matters.
Larry
 
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Yes this is another source of possibly fatal error since there is no way to correct a die that has threads that are crooked or run out to the sizing chamber.
The best way to check this that I can think of is chuck a brass or aluminum bar in the lathe and set up a taper attachment or the compound to match the interior taper of the die body. One the taper is made to match the die interior just tap the die body on the spud and check the threads on the OD.
A good machinist or tool maker can make you a die that has both the ID and OD machined without rechucking the part. The problem is the heat treat. If the die warps when heat treated then you might have to start over.


There is also the matter of whether the ID of a die is coaxial with its threads. That would take a more elaborate setup to check.
 

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