Steel rule die tonnage requirement

I need to make rubber washers (just a spacer) with a 2" ID, 2 5/8" OD. I've been using .063" neoprene, 50 or 60 durometer.

A few years ago, I made a little cutter out of 2 sizes of thinwall steel tube, sharpened and welded to a plate. Would press onto a piece of 1/2" UHMW, in a bottle jack style hydraulic press. Worked well enough, but not well, and the "die" would wear out frequently needing resharpening.

Recently, it went from well enough, to not working at all - thinking McMaster may have sent me the wrong rubber durometer, but buying the next harder one didn't help.

I need to get a better method for these. Looks like steel rule die is the answer, as long as I can press them on something I own (annual required qty doesn't justify spending a lot to buy a clicker press).

Ideally, I'd hit these things 1 at a time on a Diacro #2 punch (4 ton punch). With about 14 1/2" of steel rule, does 4 tons seem feasible?

Do you know approximately how much pressure you were using with your bottle jack? If I understand correctly you are going to be performing the same process and just using a different material for your cutter and a different press. I tried computing what force I would need for a die once and used all the formulas for area of the cutter, durometer, material thickness etc. and the results were all over the place. I ended up just trying it and adjusting the pressure accordingly. I should have done that to begin with.

I don't know how much force I was using, but probably more than 4 tons. However, that was with tube that's much thicker than a rule die, and certainly nowhere near as sharp. Dead sharp would roll the edge over.

Was more bludgeoning my way through, rather than cutting.

Also, on my old setup, the UHMW seemed too soft. I'd have to cut into it a fair amount before it would sever the rubber. What's the generally accepted backer? Hard plastic like plexiglass?

Just spoke with Apple Die, and the guy came up with about 4 tons as a rough tonnage estimate, without me mentioning punch capability. That's close enough that I'm going to go ahead and order a die and see how it works.

Just waiting on my RFQ to be returned.

Ended up ordering my die from Amark dies. $58 and 1 day turnaround. Can't beat that. Will absolutely use them for future dies.





Turns out 4 tons is more than enough. First test part went clean through the neoprene, and quite a ways into the 3/8" UHMW backer I was using, too.

Ease off a bit, and it cuts perfectly.



For kicks and giggles I also tried the die in a 1 ton arbor press, and it almost took care of it, but not quite. A 2 ton one would probably be fine.

I was guessing 2 tons.
If you can make some sort of stroke limiter you can advoid chewing up your cutting pad.

We sell and service swing-arm "clicker" type hydraulic press's that use rule dies to cut out leather and other heavy textile materials (like rubber), and our rule-of-thumb is to figure 1 ton per 6" of cutting edge.