Thread: Discussion Change sun 12 bladed 70mm
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Old Feb 03, 2013, 04:05 PM
WhalleyB0Y is offline
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Originally Posted by PeterVRC View Post
Whalley.... I assume/hope that the shaft adaptor filing was really just to clean out the burrs from the grub screws!! If it was cleaned up and still too small.....never file out a shaft adaptor! hehe
At best you will make it worse than it was.... they need to be DEAD TRUE. Which maybe it wasn't even in the first place, but doing something by hand is unlikely to ever improve anything!

So the first thing to check for is burrs from the grub screw holes. They don't clean them up at all internally, so there can be sharp edges in there. they will actually clean up when you push a shaft through them - IF your shaft fits the real hole diameter ok.
You can use some other shaft to clean it too.... a file is not a great idea, or at least be VERY careful.

If a shaft does not fit at all, because it truly is a bit larger than the shaft adaptor hole, then HEAT UP the shaft adaptor. This is actually a good situation to have! As long as it is only that bit too small.....
Heating it up expands it, so the hole gets 'bigger' temporarily.
Heat it up with a hot air gun preferably... or over a flame (not too close to go black from soot!)... and put it onto the motor shaft. You then have a rock solid fitting result!

The opposite of this is having a LOOSE motor shaft, which you can never truly fix 100%.
So you really want a firm/snug fit... or too tight.... rather than loose/sloppy.

You don't get much choice... you get what they gave you.
If it is a terrible shaft adaptor you really should buy an aftermarket one from ExtremRC or Tamjets.
But also beware as it might be your MOTOR shaft that is the part that is not to specs.... eg a 4mm one that is really 3.85mm etc. So check that with a vernier too.
Lol no, sorry I think I confused you. I didn't file the shaft adaptor itself but the hole it passes through in the mount. My bad for not being clear.
In the meantime I benched the second pair same setup. The fan was pushing a 1000 watts steady @ 76 amps but I couldn't get the spinner to balance. At mid throttle it sounded rough but at wot it was smooth. Without the spinner the fan was dead quiet and smooth for the whole throttle band.
How do I balance this spinner (aluminum one)?
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