Black Delrin (acetal) turns nicely and produces good threads. I've also found that it can be sanded with a random orbital sander and 220 grit paper to make a gorgeous matte finish that has a warm velvet feel that also resists fingerprints. For round parts, you should be able to create the same effect in 30 minutes in a rotary tumbler.
Another good option would be aluminum. You can black anodize the parts yourself. There are plenty of YouTube videos demonstrating the process, as well as inexpensive kits from Caswell Plating. You could also powder coat the aluminum for a nice durable finish that doesn't require as much chemistry. Either put a very thin coat of overspray on the threads or mask the threads to prevent them from being powder coated. The thread masking could be done as part of the powder coat fixturing. Thread the part onto a threaded fixture to hold the part when applying the powder coat and baking it to cure it, while also keeping the powder off the threads. On 02/23/2015 11:46 AM, Kirk Wallace wrote: > I am using this site as a reference for making some telescope eyepieces: > http://home.fuse.net/astronomy/ > > Larry chose to use urethane to make the blanks for machining. My > experience with urethane is that recipes range from rubbery soft to > pretty darn hard, but not fully hard. I need something that can take a > .6 mm pitch thread and stand up to assembly cycles. PVC pipe is the > wrong color, threads okay, but the threads smear easily. Acetal works > very well, but can't be bonded or painted. Polyester resin might work. > I'm also considering injection molding blanks from PLA. > > I'm wondering, are there forms of urethane that have the same > characteristics as acetal? Are there other materials that would be better? > > ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=190641631&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
