Split Dies

[Old Navy]

Been reloading since 1963.
Never have seen nor heard of this.

Same since 67. Heat treated too hard maybe?

 

[Walt Krafft]

Hoop stress failure is not uncommon in high production form dies. Infant failure could be a manufacturing defect. If older might just be fatigue.

 

[kiwijohn]

I had an RCBS .308 form die split on me, when I was resizing mil surp, to then squeeze down to .260. I sent them pictures and they sent me a new die.

 

[PigButtons]

I think you guys are tightening the lock ring set screws too tight and it's point loading the die body. ( sarc )

 

[Bill K]

Started reloading in 1955, have used a whole number of various make of dies, beginning with C&H and Herter's back then. Now have Lee, RCBS, Redding, Whidden and still use the old original one's on some calibers, have never split a die body.

 

[K22]

I thought I've seen and heard everything after reloading close to 50 years but this is a new one! Very interesting and puzzling.

I have to cam over on my full length sizing dies to achieve a .001 to .002" shoulder set back but I've never had a die split like those illustrated in this post. Most of my dies are at least 25 years old. Now that I said it one will probably "split" on me tomorrow.

PS: Over the years I've loaded for 222, 223, 243, 270, 308 and 30 06. Dies used: Lyman and RCBS. Some of the dies have seen literally thousands of reloads with "cam over" settings.

 

[JFrank]

1st case, wow!
I might of lost my s#!+ right there.

I’m suspecting a heavy bottom of die to shell holder contact, how about you?

 

[DickE]

Learned something new today.

 

[DaveTooley]

never even heard of it---wow. gotta be bad alloy???

Case hardening too thick. Been there done that.

 

[243winxb]

What case lube is being used on all these split dies? May give a clue why.

 

[Bc'z]

I’m suspecting a heavy bottom of die to shell holder contact, how about you?

Same.

 

[M-61]

Hoop stress failure is not uncommon in high production form dies

Any chance you can share what that is?

Hope I'm not the only one that does not know.

 

[Fotheringill]

None, but now I have something else on my "worry" list because of this thread. Only kidding.

 

[Walt Krafft]

Any chance you can share what that is?

Hope I'm not the only one that does not know.

A round die, as it squeezes down on a case, is being stressed in a circle like a hoop. Just like bending a wire causes the wire to eventually fail, constantly stressing a circular die can eventually make it fail. The failure occurs perpendicular to the stress, so a round die will split lengthwise.

 

[M-61]

Thanks Walt.....clear understandable explanation.

 

[STOMP442]

I'm using Hornady Unique for lube. Same lube I have been using for years. Like I said I have been reloading for quite a few years and been doing it the same way. Never had die failures until now.

 

[243winxb]

Hornady Unique for lube

RCBS has said wax build-up can cause brass to get stuck in their Fl sizing dies. Could lube buildup have an effect , exerting more outward pressure on the die?

No idea. Just asking.

 

[okie]

Case hardening too thick. Been there done that.

that makes sense

 

[DaveTooley]

I was making custom dies 35 years ago, pre RUM days when we used the 404 Jeffery case then for an improved Lapua case. Never cracked a die. Then I had a few 243 AI dies that cracked. I called Richard BeeBe (SP) at Redding. He told me my heat treater tried to help me out by putting a thick skin on the die. I usually had to wait or pay extra for a thin skin. They were used to treating solid parts.

 

[okie]

I was making custom dies 35 years ago, pre RUM days when we used the 404 Jeffery case then for an improved Lapua case. Never cracked a die. Then I had a few 243 AI dies that cracked. I called Richard BeeBe (SP) at Redding. He told me my heat treater tried to help me out by putting a thick skin on the die. I usually had to wait or pay extra for a thin skin. They were used to treating solid parts.

definitely a case where more is not better--I learned something today!!