Definitely go with wood first. Plastic is an entirely different animal. It’s nothing at all like turning wood.
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I made a POM KnKN today to see if the press fitting would work well with the material. It does. It also opens up dyeing options (unlike polycarbonate).
Making this one helped me to dial in my axle length for press fits. You can see on this one that I made the axle about 1.5mm too long and so when I assembled it using my arbor press, the axle went in too far causing a bulge in the face of one half.
The only problem with using POM is it’s difficulty to finish nicely. It always ends up looking pretty scratched up with use.
I was also hpping that it would take less time to finish, but it didn’t.
I will keep exploring using POM for the model because it is cheaper and more readily available in rod form than polycarbonate.
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I’ll buy it
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Just wait until you see what I’m about to post about 30 minutes…
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Look outstanding Glen! I bet a run of these would be a mega hit.
Does PC have higher density than wood and therefore create generally longer spin times? Is the weight similar to wood with same dimensions or did you have to make any modifications to your original dimensions to accommodate the PC material?
Seems like this highly polished PC would create a bit less friction against the string as compared to wood which I’d think would also increase spin times. Has this affected the response at all though?
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The density is significantly higher than wood, that’s why I make these PC models undersized, otherwise they would be way too heavy, something like 100g.
This Button is 85% the size of a regular Button at 48mm diameter. Every aspect is 85% of a Button except for the response holes.
Interestingly, I polished the response area of this one, unlike the PC KNacks I made and it responds even more reliably and smoothly. I have no idea why.
The spin time is comparable to a full sized Button.
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Thanks for the details! Makes perfect sense now!
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It just occurred to me that maybe you could experiment with a full size PC model that has a “cup” and thin walls to get the weight down. Not sure if PC is strong enough for this though? Is this something you’ve considered?
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I considered it, and there are a lot of problems with that.
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The next experiment is to make a Knick-KNack that is 88% rather than 80% the size of a KNack. This will bring the diameter to about 50mm instead of 46. The original size is good, I just want to experiment with a larger one to see how it feels.
I also would love to make a yoyo out of this stuff, which is basically the most advanced, semi-crystalline thermoplastic available. Its very tough and very resilient under all kinds of tests. Just look at that price!
It probably won’t happen. BUT, if I can find it in a rod diameter, of 1/4", I may use it for the axles in a new UHMWPE Survivalist model. It has a melting point of over 250 degrees Celsius, so no fear of the axle melting.
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Do you flame polish those?
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No. I don’t think you can flame polish polycarbonate.
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Ah okay, does Vapor Polishing work?
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Yes, if I can get my hands on whatever super nasty chemical works on polycarbonate.
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Seems they use Methylene Chloride/Dichlormethane to do this. Don’t know if that stuff is readily available somewhere. And you are right it’s pretty nasty stuff. The good thing is it does not seem flammable in normal Air.
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It’s pretty rare for me to make unresponsives these days because is rather difficult to do using only a wood lathe. But I have rethought my methods and tooling and now making them is easier as well as more efficient and reliable. This one plays like a dream and is virtually vibe free (for those who care about that kinda thing).
I was looking for a new slightly undersized yoyo that is on the heftier side (67-68g). I ended up trying to make what I was after, and it turned out really nice. The only complaint is that it feels a lot floater than I was going for, but oh well, its a bit of a side effect of making yoyos from POM.
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That looks fantastic. I have to say, in my opinion you overestimate the vibe in your POM yoyos. I completely understand why, as you don’t want to have a buyer crying that their handmade yoyo isn’t 100% vibe free. However, at least the cherry red Spinworthy I have is a fantastic player, and has become my go to plastic.
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Thanks, mate! I’m glad you like it!
I hope to make a few more POM yoyos, maybe even experiment with putting steel rings in them. Any idea where I can get myself some of those @yyfben2.deactivated?
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