Juma
- Thread starter whammo57
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It is harder than the highest rated standard polyurethane rod for sure. I use poly urethane for the universal shaft spinning lathe pins. And I have experimented with almost every hardness of poly rod that can be ordered and Juma does not machine like any of them. So this is a mystery to me, if it is a poly based material. If they said polymer based material I would have agreed, since that is a larger family of materials than polyurethane..
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Their web site doesn't really tell you a lot of info. I notice when you use the router on it .... the black dust is all over everything. It makes great slot rings.
Kim
Yeah. My guess is that a glass powder or something like that is a base & the urethane is the resin agent that holds everything to form. That would technically be a "polyurethane" material without giving any specific data. It's much harder than typical polyurethanes & abrasive to HSS blades. I'm almost afraid of using it because the fine dust it produces. Over time it'll wear heavily on lathe ways & such. If it can eat away HSS, it'll have no trouble with hardened steel.
With carbide should have no issues as well, right Eric?
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Carbide seems fine to cut with, but your lathe bed ways & cross slides aren't carbide. May not do any damage at all, I don't know. But i'm going to quit using it until I know what it's made of.
You think it's any worse than G9 melamine rods or glass filled acetal ?
I usually turn them down on the taper machine down with 20 thou or so then do the rest on the lathe.
For starters Juma is a name John came up with at Atlas. 2nd it's a power based material mixed with G-10 EPOXY . I helped test this stuff years ago and it played great but I would crack them when breaking with the stuff . I was than sent a new piece and was told it had more G-10 epoxy in it and so on and so on till it was right. all in all I love the stuff it sands awesome for blending , plays firm but with a quiet hit and does not feel like glass breaking when you strike the ball. I sell all my cues with the stuff also I have one on my new cue and have been breaking with it and no problems here , love it. D Hill
There is an other version of material that the company makes with glass in it. It might be that one.
The fine powder is rough on the lathe bed. I have noticed that it sounds gritty when moving the slide over the dust. I clean it off and lube it after cutting Juma. I always wear a respirator anyways.
Kim
I'd guess the powder is glass, especially if they're mixing with G-10. Makes sense why it tears up HSS. Thanks for the info, kind of along the lines of what I expected.
Nothing is worse than G9....except maybe diamond powder dust all over the machine. Hardened steel ain't very hard when compared to glass or diamonds. I won't cut G10 or G9 anymore, and likely will not use Juma anymore, either. Might have to do some testing on it to see how abrasive the dust is.