Another design/materials Q.....


Apropos of my wiper Q, here's more info, with another Q.....

Since I don't think this wiper thing is going to be so easy to solve, and since from a sliding/friction pov it don't get much worse than alum on/in alum, I'm experimenting with making the slider ITSELF out of a nylon-ish/UHMW material. Altho I would still like a wiper, a plastic slider (and the lubricity thereof) should intrinsically help, from a friction/galling pov.

So the Q is: what would be a good substitute for the alum slider? I'd like a good combo of strength and lubricity, as stuff is attached to this slider, via 10-24 screws, 3/16 pins, etc. The 10-24 screws will not be threaded into the slider itself, but rather thru the slider and into another pc of substantial alum.

I've always liked nylon, delrin, teflon. Nylon seems to be a kind of ref. std, ito plastic strength, durability, and it seems that altho it doesn't have the lubricity of delrin, it's OK. Would delrin be better? Anything else?

fyi, the actual size of this particular slider is approx. 3/8 x 3/4, with a

1/8x1/8 rabbet on each side (so the captured sliding part is 1/4 x 3/4), with a 4.5" L

Any class of materials I should specifically avoid?

Idears, opinions?

I suppose I could test various materials, by buying or making something of a power hacksaw, and just let various materials reciprocate for a few days, see what stuff looks like at the end. Hopefully I won't have to go that route, tho.

Reply to
Existential Angst
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There are too many variables here to give you a definitive answer.

Do I understand that this "piston" doesn't have to seal anything? If so, any of the plastics you mentioned should work.

How much of an issue is friction? If a great deal, then UHMW polyethylene. If less of an issue, any of the others will do.

What is the specific load? You probably only have a qualitative handle on this. If so, you're on your own.

Is there some detriment to having a bit of clearance? If so, then how much?

If the performance or the service life of this thing is very important, then you need answers, or some tests, to answer it. If it's not -- if you can have some clearance, if you don't need very low friction, if there is no sealing involved, if the specific loads are within the range of these plastics, and if it doesn't have to cycle millions of times, any one of them should work.

Metal against metal would be my last choice.

Reply to
Ed Huntress

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