What accuracy to expect from chinese spindles

[ftkalcevic]

I've just received my water cooled 2.2kW chinese spindle. I've wired to the VFD and it spins; a promising start.

I set up a dial indicator on the inside of the spindle taper to measure the spindle runout, and on my indicator with 0.0005" divisions, it only moves from 1/2 to 1 indicator, .0005" (0.0127mm), higher than the 0.005mm "runoff" promised.

I then chucked a ground 10mm bar using a 10mm collet (cheap ebay collets) I get about 3 - 4 divisons or about 0.002" (0.05mm) run out.

Is that a lot? Will I notice it?

I want to use my spindle for machining wood, aluminium and drilling PCBs, with drills down to about 0.5 mm.

I've noticed the inside taper of the spindle is quite rough, compared to the collet holder I have for my mill drill which looks ground.

Thanks,
Frank

[liaoh75]

Hi Frank,

I have a 3KW Chinese spindle and the accuracy is more than adequate for wood. I've done quite a bit of research on chinese spindle and found that there are over 20 companies in China producing almost the exact same product. They look the same but the quality varies from one company to the next. I did a measure on mine too and it is well within specs. You'll get more inaccuracy from vibration and flex than you will get from the .002" run out in your spindle. If you are not making molds, you should be ok. PC boards should also be ok. Good luck!

David

[ftkalcevic]

Thanks for the reply.

I'm still wait for the postman to deliver some precision collets before I decide whether I am happy with the accuracy, but given that the ebay seller listed the spindle as 0.005mm runout, and I'm currently seeing 3 times that at the spindle and 10 times that after mounting a test bar, I was wondering if anyone has got a spindle better than this?

Is it worth arguing with the ebay seller?
Should I just accept it as it is?
Is there anyway to improve the accuracy? I was thinking of mounting the spindle on the my lathe's bed and trying to turn or grind the taper under the spindle's power. Anyone done anything like this?

Frank