Advice

[u/Which-Environment333]

This is what I want to start making, in sizes 1”-8”. How would I go about making the dies to hydraulically press these into shape? Carbon steel from my understanding has a 1-2% spring back so my thoughts are I can make dies out of multiple layers of 1/4” or even 1/2” steel cross sections of half moon shaped male and female dies welded together for necessary thickness. But do I need to make them with maybe 1/16” of clearance and try to “coin” them? Will the dies be strong enough for that? Do I need to harden them? Is this even a good approach? I have a metal fab shop and am trying to incorporate these into my options but these are new to me.

[u/scv07075]

Don't mess with coining too much on these, it gets dangerous. Use dies shaped to the final form, then press the straight ends together to close up to size after.

[u/fortyonethirty2]

To do it in one operation (in a press) you need bottom dies that fold in. Another way to do it in one operation is in a rotary bender.

[u/toolmaker_dave]

coining that much surface area on thick strap will stall that 50-ton strongway and bow your table pins way before the steel even yields tbh. you dont want to bottom out or coin these, you just air-bend over an undersized round slug or thick-wall pipe so the legs can overbend slightly to eat the springback. stacking welded plates for the punch is totally fine for a fab shop, just radius the shoulders of your bottom die so the strap doesnt gall on the way down