Spindle runout

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RSG
Posts: 950
Joined: Fri Feb 04, 2011 9:59 am
Location: Ontario, Canada

Re: Spindle runout

Post by RSG » Sun May 14, 2017 8:13 am

This is all very interesting and I am learning a lot. I appreciate the input.
Vision is not seeing things as they are, but as they will be.

RSG
Posts: 950
Joined: Fri Feb 04, 2011 9:59 am
Location: Ontario, Canada

Re: Spindle runout

Post by RSG » Sun May 14, 2017 8:26 am

ctwo wrote:looks like a ridge on that collet. Maybe they are soft, and you said it's been crashed a couple times? Even though I mentioned grinding the spindle in place, it would be the last resort, maybe even after replacing bearings.
I measured the end of the collet at three different points with a micrometer while it was sitting on my bench and found it to be very consistent. It seems very rigid contrary to your suggestion above though and I was wondering if that's why the spindle is galled on three sides and perhaps a softer collet wouldn't do that. I tested runout with a few different collets yesterday and they were consistent with the 3/8" collet with the 3/4" being the best. I'm using an endmill in the collet to touch the DTI up again instead of drill rod too, not sure if that's better or not. I am going to look into a better 3/8" collet and do my tests again. I figure if I can get the same amount of runout as the spindle with new collets that should be better than it is now.

How can you tell if the bearing are bad without taking them out?
Vision is not seeing things as they are, but as they will be.

spro
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Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Spindle runout

Post by spro » Mon May 15, 2017 12:22 pm

RSG wrote:
ctwo wrote:looks like a ridge on that collet. Maybe they are soft, and you said it's been crashed a couple times? Even though I mentioned grinding the spindle in place, it would be the last resort, maybe even after replacing bearings.
I measured the end of the collet at three different points with a micrometer while it was sitting on my bench and found it to be very consistent. It seems very rigid contrary to your suggestion above though and I was wondering if that's why the spindle is galled on three sides and perhaps a softer collet wouldn't do that. I tested runout with a few different collets yesterday and they were consistent with the 3/8" collet with the 3/4" being the best. I'm using an endmill in the collet to touch the DTI up again instead of drill rod too, not sure if that's better or not. I am going to look into a better 3/8" collet and do my tests again. I figure if I can get the same amount of runout as the spindle with new collets that should be better than it is now.

How can you tell if the bearing are bad without taking them out?
Last to first: You can tell a precision bearing is bad Because of taking them out. (messes them up)
The spindle appears galled and that doesn't mean the bearings are bad. It may come back to that pin/key which must have been gone or damaged. Where did it go? What is part of it doing? Grinding an inside taper is very involved/ difficult without experience. There are so many ways to make it worse. That is why I was thinking how a "standard" of an R-8 shape could be located for bluing and possibly lapping the spindle taper. The R-8 isn't a self aligning taper, it depends upon a straight, centrally located drawbar.
I remember now how terrible my M/D was. The drawbar was obviously not on center when viewed from atop the spindle pulley. I set up some fixture next to it and found the actual center. Then turned a shaped washer which actually located, forced the drawbar to center. It improved the operation.

RSG
Posts: 950
Joined: Fri Feb 04, 2011 9:59 am
Location: Ontario, Canada

Re: Spindle runout

Post by RSG » Mon May 15, 2017 12:26 pm

Thanks Spro,

That centering washer idea for the draw bar sounds like a good Idea. I'l have to look into it.
Vision is not seeing things as they are, but as they will be.

spro
Posts: 7053
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Spindle runout

Post by spro » Mon May 15, 2017 2:07 pm

Well I may have muddied the water about that. I put a bronze sleeve and then shaped the thrust washer. As it came, it had two loose flat washers and the drawbar didn't have a thick neck to center it well. The R-8 Is fairly self centering but that bias of the draw bar was too much.

joshuaj97
Posts: 41
Joined: Sun Jan 03, 2010 11:50 am
Location: woodland park CO

Re: Spindle runout

Post by joshuaj97 » Mon Sep 04, 2017 10:32 am

When do you find this affects your work the most and causes trouble?

RSG
Posts: 950
Joined: Fri Feb 04, 2011 9:59 am
Location: Ontario, Canada

Re: Spindle runout

Post by RSG » Mon Sep 04, 2017 5:03 pm

joshuaj97 wrote:When do you find this affects your work the most and causes trouble?
To be honest now that I think about it hasn't really effected my work at all, I compensate for it. if you use an edge finder then you know it's central to the spindle, how much out depends on the run out I guess. Obviously one would want it to be minimal.
Vision is not seeing things as they are, but as they will be.

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