Delrin vs UHMW

[Jaladel]

Hi,

Is Delrin enough better than UHMW that I should make the plastic parts out of it instead of UHMW? Delrin seems pretty spendy.

Thanks

[Den-Den]

Delrin is much better for things like acme nuts or sleeve type bearings if running against a smooth surface. UHMW would be better for sliding rough surfaces against (not really applicable to most cnc needs). When subsituting materials, it is impossible to compare the two without knowing what they will be used for and difficult to compare cost vs value even with lots of information. (a few dollars is important to some people, better performance is more important to others)

[cam1]

Delrin machines like a dream, UHMW not so nice.

regards

[Jaladel]

Delrin 2
UHMW 0

Looks like I'll be saving up my pennies then, thanks guys.

(looking at the JRGO plans and how to modify them to use my ACME thread (1/2-10)

[ynnek]

If what you are making needs the ability to hold precision during the machining process you need to use delrin. I use both platics where I work, so I can tell you this from experience. Another plastic to use for making nuts would be blue nylatron.

[AlienSteve]

I went to my local plastic supplier for Delrin, told them what it was for, and they recommended UHMW. I was warned that it is a little more difficult to machine than Delrin but that it would last longer and have less friction.

This website seems to agree:
http://www.johnsonplastic.com/plastics.php

"UHMW has one of the highest impact strengths of any thermoplastic and has excellent abrasion resistance, tensile strength, energy absorption, resistance to stress, cracking, and coefficient of friction properties. UHMW coefficient of friction is significantly better than nylon and acetal and is virtually the same as Teflon® but has superior abrasion resistance.

UHMW in sliding applications will out wear steel 10 to 1 and stainless steel 6 to 1."

BTW, acetal is the generic name for Delrin.

I see that there is now Delrin AF, which has threads of Teflon added. Based on the quote above, however, I'm sticking with UHMW for now.

Also, UHMW cost me $3 a pound versus regular Delrin for $8 a pound.

[grahamshere]

I used nylon to build my lead nuts and work good so far but its a you know what to machine but its cheaper than delrin. I'm using uhmw to build my bearing trucks though like these ones, what do you think, should be ok?

[AlienSteve]

You should know that nylon absorbs moisture and changes size when it does. So your nut may tighten or loosen if the humidity changes.

I recall reading about someone who'd made his own stands for the company's tradeshow display using nylon as expansion fittings. He said they worked great until then went to a show in an area with high humidity, then they couldn't even get the pipes into the openings due to the nylon swelling.

UHMW won't absorb any moisture. I don't think Delrin/acetal does either.

[grahamshere]

Great, they didnt tell me that at the plastic store, and I live in BC were rains 90% of the time, well my work shop stays dry some what, hope it works till I get some delrin. thanks mate. Graham

[2TALLTARY]

delrin is the best for machining and uhmw is very tough material but not so good for machining. it is better used in the food and dairy industry and for sliding and wear applications. if you want uhmw or delrin, a great place is Your Source For Plastic Sheet, Slab, Rod and Tube. 866-832-9315

[nokillzone]

Originally Posted by grahamshere I used nylon to build my lead nuts and work good so far but its a you know what to machine but its cheaper than delrin. I'm using uhmw to build my bearing trucks though like these ones, what do you think, should be ok?

Hey can you send me a drawing or blueprints of what you made .. its interesting !!!

[judleroy]

You really need to get some srap pieces of each so you'll know what your dealing with first hand. The fact that uhmw wears better in some situations does'nt make it right for your application. Since I still am not sure whats being made I could'nt begin to say which is better.If your using uhmw for a nut or anything that will be compressed then delrin is the clear winner. Uhmw has incredable impact strength and long wear when sliding against metal thats true. It is also very soft so it can be dented easily. When used as a nut it will compress and the nut will get loose very quickly and the threads would be more likely to strip out under reapeated heavy loads. Also you need too remember to check what temperatures each melts at because friction causes alot of heat and long cycles at high speeds is where delrin would excel over uhmw.
judleroy