[SweetJustice]

I finally found myself in a place with room for a workshop. Got my taig mil (the CR model with the 1/4 hp motor) out of storage and put an ER16 spindle on it. I've done a bunch of cutting with it, and mostly everything works great.

The problem is when I put it on either of the two fastest pulleys. It turns maybe 200 rpm, and won't ever get up to speed. Doesn't matter how loose or tight the belt is.

Doing the reversed ohmmeter test on the start cap suggests that it's OK. I'm not sure what else to try.

[Jeff-Birt]

Well, if the motor comes up to speed without the belt on it points towards the spindle itself. If it is a new spindle then you may want to run it for a few hours to break the bearings in and see how it does at higher speeds.

[SweetJustice]

Thanks, that seems to have worked. Ran it for a half-hour on the third-fastest pulley, then it would spin up (barely) on the second. Ten minutes of that, and it worked on the fastest.

The spindle itself seems mighty hot after that (uncomfortably hot to the touch) but I'm hoping that's just because it's still breaking in.

[Jeff-Birt]

I cut parts all weekend at 10,000 RPM (top speeds) and the spindle just got warm to the touch. If it is getting really hot it could be the belt slipping or a bad bearing (or two).

Was this a new spindle?

[SweetJustice]

Yes, brand new spindle from A2Z. I'll check with them.

[SweetJustice]

Update:

I got a very helpful explanation from Tim at A2Z. He says that the overheating behaviour I'm observing is due to pre-load on the bearings, and is to be expected while they seat in. Basically I just need to be careful at high speeds for a while, and shut it down for a cooldown period when things get too hot. He said it took 40 hours on his taig.

The hard starting is likely because I have the older single-capacitor taig motor, which doesn't have great starting torque. It should go away as the bearings seat in.

[M250cnc]

Follow this link to see how to run in your bearings.

Lubrication - SKF.com / Products / Interactive Engineering Catalogue/High-/super-precision bearings

Phil

[SweetJustice]

Also:
http://www.sherline.com/4335inst.pdf