Delrin?

Delrin is just lovely stuff to machine! (really, not being facetious).

Both McMaster-Carr and MSC carry small cylindrical stock in Delrin (acetal) plastic in natural and black, and usually in MDS-filled versions. It has good stiffness, elasticity, chemical resistance, and lubricity for all sorts of mechanical parts.

However, if your rubber is being cut by the metal, the plastic will be, also. Before wasting the time to make the parts, give a good look at the impingement angles between the roller and the metal. Ideally, the roller shouldn't be bearing right on the bitter edge of the cut metal, unless you're rolling a "zero radius" bead on the edge. In that case, you need a hardened, polished metal roller. Avoid skating and sliding, and a polished steel roller will be "non-marring".

LLoyd

LLoyd

So is Polypro other than sweeping up all the snowflakes from cranking the mill handles as fast as I could. Made a nice set of grippers for a part flipper for a conveyer the other night.

We used delrin where I used to work in combination with serated steel rules to cut unbacked carpet for automotive shelf panels. It seemed to hold up well since some fibers got shoved in the grooves which alieviated the effects of cutting in. Since the Delrin was used as the score plate, we also had the option to move the plate around a bit to distribute the wear.

If cutting rubber, I'd go with your idea of cutting against hardened steel though. That is how we diecut wood fiber based items and I don't see any reason rubber wouldn't work the same.

Wes S

Agreed, but don't ever let it burn. It is polymerized death. Like a nest of fire ants swarming down into your lungs.

But then your nitrile gloves are polymerized cyanide. And your cookware polymerized fluorine.

Amazing that these things are allowed on airplanes.

HI, FOR DELRIN, TRY TRANSMISSION DEVELOPMENTS, 01202 675555, ASK FOR ANDY, THEY STOCK DELRIN, AND SOMTHING THAT SIZE HE MIGHT EVEN SEND YOU A SAMPLE. THERE VERY HELPFUL. REAGRDS WILLIAM

Delrin is POM. It is very nice to machine, but quite hard. I would use PA, it is a bit softer and machines well enough with sharp tools and not to light cuts.

Nick

I have drops of UHMW from 1-1/4" thick sheet, they are discs over 3" diam

Thanks for all the replies. I should have mentioned that I will be rolling a fairly deep 1/2" curve down the length of slightly wider strips of 16ga.sterling silver with a pattern stamped on one side, hence the need for non-marring. I've already mirror-polished the mandrels, but where the female die transitions from groove to flat it cuts into the soft metal. I've rounded this transitioin somewhat and it helped a little, but a resilient roller probably is going to end up being the best approach; just looking for the most appropriate material or any ingenious ideas on how to accomplish this.

Mouse

No. Delrin is a brand name for polyacetal, not polyoxymethylene (POM).

Even DuPont doesn't know that!

To edit the same error in Wiki, click here:

Nick

(You had to go to Hong Kong to find that?)

Here is what DuPont (in the USA) sez about it:

Delrin® is the DuPont registered trademark for its brand of acetal resin also commonly [RK: but imprecisely] referred to as polyoxymethylene (POM).

Not all POM (understood as a family of polymers based on polyformaldehyde plus other things) is polyacetal. Polyacetal is more than POM (understood as polyformaldehyde per se). It's one of those confused polymer descriptions. Depends whether you mean POM proper, or something derived from POM or in the POM family plus other components.

It was the first one.

I only used the abbrev. POM and PA. Delrin is POM, as DuPont says. The "but imprecisely" was your addition (and you noted that).

PA is Polyamid PA is NOT Polyacetal POM is a Polyacetal or Polyoxymethylen

Nick

If you need to work the edge with a compliant roller, I'd suggest some of the high-durometer urethanes, rather than a more rigid plastic like acetal. "Durothane" brand comes in at least two durometer ratings, and is a two-part system you can cast into intricate and precise shapes.

LLoyd

That is my BIG complaint with all this #$%^&** using abreviations without defining them the first time one is used. Some people seem to think they can just make up an abreviation and everyone will know what they mean. ...lew...

They are international standard.

Scroll down to end of page for a _partial_ list.

Did I?

Nick

Found a nicer one:

They also have a list of brandnames and the abrevs "I invented".

Nick

But it is not so easy to drill a 1/2" or 5/8" hole. The plate will flex, then then quickly drill and chip around the edge of the hole. I learned that I had to put a vise in the mill vise that holds the Delrin plate very close to the hole being drilled.

Jon,

Thanks for the plastic rounds, they look great and the stuff looks like it will stand up well to my applilcation. You never know with this group who is going to show up with the right information or surplus parts.

mouse

J> I have drops of UHMW from 1-1/4"