Thank you for the link. The final piece needs to be around 0.5" OD at the largest diameter. I think 1.0" diameter would be a little too large, but I noticed the same seller has both 0.5" OD and 0.75" OD rod, in the same red color. I put both OD sizes in my eBay "watchlist". Much appreciated!I don't know how big your end piece is, but here's a link to some 1" diameter red acrylic rod on ebay. Plenty to experiment with and to get things correct.
Yes, I'll have to polish it. I'm hoping successively finer grits of wet/dry paper will do the trick.Sure you can turn plastics on the lathe; you may have some polishing to do afterwards if you want the part to have a clear shiny finish.
Also drill to size, don't use a pilot drill as is often done with metals. Plastics can crack and shatter when trying to enlarge an existing hole
-Mark
YIKES!!!!
I've considered that approach! But as I mentioned, color matching is important to me, so I think my best chance of success will be to get a piece of the same material the other two knobs were made from. That kind of forces me to resort to a Millers Falls "804 series" screwdriver, which was made the same year as the Rivett 1R.I'd vote for considering a casting, with dye to color the stuff; Tap Plastics has transparent dyes
for this sort of thing... an epoxy or urethane casting would be nice and durable, compared to acrylic,
and you can get a good mechanical bond to the machine part by embedding it while
the resin is still soft. Machining to finished shape, or turning a mold, will satisfy the need to
make swarf...
I have several cutters that I keep nice radii on... one of them will end up on the front lines!You will also want to have a nice radius on your turning and facing tools. That will help with the finish and keep from chipping.
Cutting oil is my blood.
Why I'm committed to using plastic is a fair question. You're correct; I want it to look original. The first picture (of the three I posted) is NOT my Rivett 1R - it's someone else's. But it shows the appearance of an undamaged 1R. That's my end goal. Well, one of them, anyway!Personally, I'd do it on a wood lathe with hand tools. But I have a lot of wood turning experience. It will be grabby. Probably would mostly use scrapers. It would be easy to sand and polish by hand. As many have said, watch the cutting speed as you don't want to start melting / softening it. Another thing with plastics is you can/will get one continuous strand of swarf that can range from a nuisance to dangerous.
You do not state why you are committed to sticking with plastic/acrylic, why? I'm guessing that you want it to look original. It may be hard to match it anyway. So why not just use a piece of wood?