The amount of oil I need to keep the hammer lubed is incredible.  The hammer seized up yesterday.  That was fun taking apart.  Five hours later and a few mods later I'm back in business.  Today I lubed the heck out of it and the hammer is hot as a pistol.  Does the high density plastic swell?  Would brass bearing surfaces be any better?  At least I know what to do with my used oil....and before you jump on that one, lol, I've been using new 5-30w.  Marine grade axle grease wasn't the cure either. Help

UHMW as well as some other plastics can absorb water. Not sure about how oil affects it.

Great....did not know that.  I see brass sheet in my future.

Not only does some plastic take on different lubricants, it pretty much all will absorb metal dust over time. your Gibs get bigger and bigger over time. Brass Gibs are the way to go... for now.

I'm concerned for the last part of your comment. What does "for now" forebode.

Just that we are always diligently looking for a better way. As it is with allot of thing though, the older simple method wins out.

As of today I don't think there is a system for guiding a hammer head than brass oil and steel, at least not that will hold up and has near the value. 

That is all I meant.

Agreed.  I used it today for a while.  Not much.  It didn't heat up but I'm still watching it closely. Next week I'll price some brass sheet.  I like the hammer just the same.  I did a project that would take me 20 hours of work and got it down to 6.  That is a ton of time and fuel savings. Also easier on the arms.

Delrin/Acetal absorbs water more than UHMW. What is the surface finish on your ram? UHMW guides can powder and gum things up.

UHMW.  It is what the plans specified.  I'm looking at it like it is something I must have done.  I highly doubt that they would have specked it if the UHDM would not work.