while I could put beer cozies on two cup canning jars, and swing those, I’d rather get some custom bucket liners made.
internal diameter is just shy of 4", and I don’t believe they’ll take anything much taller than 5" and still swing.
not certain the chuck on the lathe I currently have access can manage 4" rod, but that’s pretty easy to figure out…and if it’s only the chuck holding us back it’s a no-brainer.
my real question is Delrin vs PTFE. Delrin is what they hand the students in machine shop…before they get to play with Alu. Pretty sure I’ve heard tell the PTFE is not as much fun.
Boss swears that they’re pretty much identical as far as chemical compatibility, and that I should just go with Delrin…cause it’s way easier to machine.
if I was making liners to swing canning jars in there, I’d use Delrin in a heart-beat, but the goal here is to make “tubes” with a ledge about halfway down to hold a screen.
When machining large volumes of delrin in production machining, you will actually release some sort of fucking formaldehyde gas. It will make you sick, sometimes for days on a long run in a small shop…or a big shop. Just keep a fan on, or if the machine is enclosed, don’t stick your head in when you open the door.
Use PTFE. Delrin is not equal to PTFE.
Delrin machines more easily than PTFE. Neither are hard to machine… unless your making PTFE seals like 18" in diameter and about .150 tall and .200 wide…then that’s hard to hold .003" tolerances…but that was on a VTL from the 50s…
Are you set on ptfe/delrin? Why do you need that kind of chemical compatibility? Are you looking to turn the adaptor into the filtering device as well? I designed and 3d printed a 4x 50ml adaptor for my swing buckets out of pla+ and have had no problems after a few hundred hours of max RCF. I also made a version to hold mason jars. Although, I haven’t had the time to test it yet. The actual printed adaptors are at my lab, but I have a pic of the rendered version. Possibly another way to achieve the outcome you wanted. Unless you are really in need of the added accuracy and chemical compatibility of the machined ptfe/delrin.
I agree this is actually a pretty good application for additive because you can print a nice hollow spacer. Delrin is chosen because it doesn’t have as much thermal instability as other plastics, making it easier to hit your tolerances. Other than that, it’s not any different than PTFE to machine IME. I also didn’t think it did very well as far as solvent resistance. I know from experience that cutting oil makes it swell
My rotor came with two 50ml adapters, and as a first approximation I was gonna grab a couple more. Based on the prices for delrin that I’m seeing, I was planning on buying from the OEM. Printed inserts would be great, and I’d rather the bosses money stayed local (you’re still in Eugene?).
I don’t usually shy away from telling the boss they’re wrong…and comparing the two chemical compatibility charts linked above, I’d have to agree they’re a long way from identical…
I have access to a small lathe, and a decent mill…however neither the guy that owns them nor myself really know what we’re doing (so starting with a Delrin project seemed like a decent idea).
As far as additive goes, yeah, that would certainly be a great solution for inserts designed to hold tubes (and I need a couple of those for 50ml tubes). I don’t currently have access to a 3-D printer…and if I did, chances are it would have been modified to fill carts at some point
@TwistedStill: Ignore the boss, and don’t huff the delrin… noted. thank you!
@pdxcanna I’m trying to keep the swung weight as low as possible, while I like the idea of off the shelf sintered disks, I’m concerned that their weight will limit my top speed. figured I’d have to play with weight vs strength to get it right. open to any and all suggestions.
Hi,
Ptfe is much more chemically resistant than acetal “aka” Delrin, which can break down into formaldehyde. Ptfe machines easy as a bar of soap, also dents like one… be carefull!
It is also stringy and often wont break chips, be carefull of getting the long noodle chips from wrapping up everything, or catching you or other near by tools. Start the hole with the largest drill you can muster, then your gonna have to use a boring bar to open up the inside diameter. Also because the material is so soft forget chucking the part by any hollow section, you will crush it. Machine if from the end of the rod and part it off, probably wont be able to face the backside with out el’scrapo!
The key for this one is hitting the same tolerances on each one, try to keep the weights the same. Afterword you can balance them by removing small amounts of material from each one until they weigh the same within reason.
not yet. there is also a curved profile at the bottom of the bucket & I haven’t yet figured out how to measure it. tempted to make a mold from the bucket so I can get my calipers on it. haven’t decided on material or mold release. grabbing the OEM bottles might be the simplest way to obtain those measurements.
