bronze wear plates?

[KenH]

Hello all, there are lots of folks here who have much experience with forging presses, especially Ed.

I see that Coal Iron has bronze wear plates on all their presses where there are sliding parts. Most of the homebuilt presses I've read about seem to use steel on steel for these places. Just how important are the bronze wear plates? To me, it seems like steel on steel that's lubed good would be just fine. BUT - I know I do NOT have the experience to determine how important the bronze wear plates are.

Bronze is expensive these days!

[Ed Caffrey]

Hi Ken!

Based on my experiences/friends with various designed presses, bronze wear plates are very much a double edge sword. They certainly do save wear on the steel portions of a press, BUT... IMO, the down sides overshadow their usefulness.
The two biggest down sides are that bronze wear plates in a press application MUST be kept lubed/greased.... and grease is a SERIOUS fire hazard in a forging press application.
I know of two individuals who had major fires in their shops because the wear plates simply got too hot, and ignited the grease/lube, and in one of those cases, the shop was a total loss.
The other down side is... with the intense stress/forces involved in a forging press application, they wear out rather quickly, much more so than in most any other application(s) and require replacement, which as you said, is pretty spendy.
I do have some bronze SHIMS that I use in Orange Crush, but they are there to take up some slack in the table's travel, and to help prevent "wracking" the press when I do something stupid.

Overall, I personally don't like, nor recommend bronze wear plates in any application that has to do with a forging press. If they're already in a press one buys, then it is what it is. If building a press, I'd suggest doing without them, and when using grease, use a synthetic that is a "high temp" variety, with low flammability.
Just my thoughts/experiences.

[KenH]

Thank you Ed, I was really hoping you'd see the question and comment. you bring some good points - as usual. This whole question (quest?) is more of an academic exercise than anything. I'm still ticked off by only getting a 9 ton press when I ordered the Coal Iron 12 ton press. Yes, the 9 ton (8 ton in my case due to mis-adjusted pressure setting) did work and I have learned LOTS from reading and using the press. Much of what I've learned is just how little I do know {g}.

I think I mentioned before Coal Iron's 12 ton press was designed for a 3.5" cylinder, but the 3" was "easier to source" (cheaper?) and they decided it worked ok. 3" cylinder working at 2550 psi is 9 ton, NOT the 12 ton the 3.5" cylinder would be.

I would LOVE to build a press, but I would pretty much build the same design I've got because it works for me to be able to move press in 'n out of shop for use. I would be working toward an honest 16 ton press - I think that would do just fine for the amount of "playing" I do with forging, etc.

I've been pricing pump, motor, control valve, and the steel to make the frame. It just isn't that hard to do, and a good bit of money could be saved vs buying. I found a local scrapyard that has angle iron for 50¢/lb. They said it's in straight sections 4 to 5 ft long, and 1X3" flat bar is also available.

Ken H>

[Ed Caffrey]

Yeah, that's the issue with using smaller, less expensive cylinders..... you have to really up the PSI to achieve any decent level of tonnage. Therein lies it's own dangers.

I honestly don't like to see a press pushing the PSI you mentioned (2550 psi), which is why I always try to pressure folks into NOTHING LESS than a 6" dia cylinder. Sure, the lines and other parts of the actual hydraulic system are typically rated for double that pressure, but forging presses are very unique in that they live/work in torturous conditions with usually not the best safety measures in place.

I always point out to consider what would happen if a hot piece of steel got onto a line without notice....even a pin hole leak would cut you in half like a light saber..... not to mention it would very likely be a flame thrower too. That same torturous environment.... consider the repetitions and the constant heating/cooling cycles, and you want to WAY overbuild the presses structure.

Bigger cylinders, with lower working pressures are the key to SAFE (at least as safe as a forging press can be) forging presses, just as ridiculously overbuilding the structure is the key to structural longevity.

All too often, those who offer forging presses for public sale fail on the side of building everything to just barely meet a relatively low standard, sometimes in the name of making a buck, but more often than not, I've found it to be a situation where those offering the tool (in this case a forging press) without ever having actually used one, day in and day out, over an extended period of time. If they had, every press out there would be built like Orange Crush.

[KenH]

To emphasize Ed's cautions about high pressure leaks, take a look at this sobering link:
https://www.mfcp.com/our-blog/bid/39...ction-injuries

[Ed Caffrey]

HOLY COW!! That is gona be a sticky on this forum!

[jimmontg]

I used to run a 200 ton punch press and now I know why all the pressure machinery, pump and fittings were behind the 3 inch steel uprights, front and back. It could only be accessed from the top and the maintenance guys always insisted that it be turned off before checking it.