Die Wobble when Threading into RockChucker 4

[Baddog0302]

Many reloading manuals tell you "before" tightening the lock ring to size a case and at the top of the ram stroke tighten the lock ring. This will remove any slop in threads and center the die in the press threads.

Another method is to place a rubber o-ring under the lock ring and this will allow the die to move and self center as the case goes into the die.

I use Redding competition shell holders that make hard contact with the die and Lee lock rings that have rubber o-rings.

There is a very good article in the Speer #9 reloading manual on how to setup your dies in the press and improve concentricity.

Bottom line, if there wasn't any slop in the threads the die would not self center and be aligned. And there is also slop in the shell holder that allows the case to self center in the die.

EXACTLY

 

[Fotheringill]

Gentlemen:

Thank you for the input. Now, back to wind and consistent trigger pull.

 

[DirtySteve]

No mention of a rubber O-ring under the locking ring...? I'll just leave this right here and watch.. lol..

 

[Uncle Ed]

No mention of a rubber O-ring under the locking ring...? I'll just leave this right here and watch.. lol..

Clean your glasses and read post #14

 

[243winxb]

See post #4.
RCBS said in an old news letter- the shell holder needs to contact the botton of the fl die to square it in the press. Then tightrn the lock ring.

Control shoulder bump? Redding comp shell holder set. Will do that.

 

[Uncle Ed]

I think it is a good idea to place a piece of metal with parallel sides on top of the shell holder when the die is in place and push against the bottom of the die hopefully squaring the die to the shell holder and then locking down the lock ring. just my thought.

Its called a feeler gauge, if you do not have Redding competition shell holders.

 

[danny]

When I thread a die (no matter which one) into my press, there is a slight wobble until the lock ring hits the top of the press. Then, it is in solidly without wobble. This happens with whichever die I am using. They are all cleaned on a regular basis.

Worry? Don't worry?

There is nothing you can do about that. It is due to the intended thread slop between the press and die threads. That is all established and there are what is called "thread fit classes" per the visual included here. As you go from three to one, the threads get looser and more sloppy, so you would feel more wobble. As mentioned, it is the mating shoulders engaging that takes out the slop and establishes the alignment. Die and Press threads are probably Class 2, maybe 1.

https://slideplayer.com/slide/5140137/16/images/9/Classes+of+Unified+Threads.jpg

Danny

 

[dcali]

As others said, it doesn't matter. Threads are not features that align things on purpose (although they do a surprisingly good job of it). If it mattered, we'd see dies designed differently - it wouldn't be hard to come up with some kind of system that eliminated the threads. That nobody has done that speaks volumes. At the end of the day, the loose fitting shell holder lets the case self-align to the die. Unless things are grossly out of alignment, that's all you need.

 

[D-4297]

A much more accurate process would be a series of "locking lugs" , similar to a AR bolt . The reason it isn't done is always the same old answer . Machining Costs ! Hundreds of Die blanks can be threaded by a Die Head at a 'cost per" , that the machining time of a CNC cutting Lugs could not come close to touching . It's always about the "Benjamin's" ......