Spindle runout - what is acceptable?

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Dale Allen

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Oct 27, 2012
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This is a short piece of aluminum stock that I used as a test.
The OD of the aluminum is .465" and I drilled into it about 1/8" with a 27/64" drill bit.
My scroll chuck is a new G3 with pin jaws and it works great.
The thickness of the rim varies between .0215" and .0225"
With the scroll chuck mounted I can see a runout of about .0015" and I get he same reading with the dead center installed. This seems consistent with the thickness variance above.





I spent about 2 hours last night dismantling the headstock of my HF lath. I wanted to get to the main spindle bearings, mainly to get the number off them and look for some replacements. One of them I left in the casting and the other was not removed from the spindle. However, both show no signs of wear and neither 'feel' like the bearings are worn in any way. However, that can be a very subjective way of determining the quality.
There is no change in the runout after re-assembly. It did need the cleaning and lube however. I would guess there is well over 300 hours run time on this lathe.

So, I'm not sure putting in new bearings would help the runout at all as it seems to be in the spindle itself. I would also guess that a new spindle would probably not be any better and may possibly be worse.

Would a runout of .0015" be acceptable? Who has checked theirs and has more or less with no issues?

I'd be interested to know the max runout on some of the new Delta and Jet models.
Yesterday I was at Hartville Hardware and they have the new 1221VS set up. However, I was not more impressed with it over the Delta 46-460. One thing that struck me funny was the fact that any tools you have in the holder above the lower belt access door would need to be removed before you could get the door open. I also detected some side-to-side movement in both the tailstock(not locked down) and the headstock spindle. At some point if it seems the replacement parts issue with Delta is resolved, I may buy one.
 

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I saw in the Supernova G2 manual this blurb.

ACCURACY: The SuperNova2Chucks are sample tested from each batch and are made to run
within the following tolerance limits:
Face Runout Maximum: 0.1mm (0.0039 inch)
Radial Runout Maximum: 0.13mm (0.005 inch)
 
Well then, perhaps I have a better setup than I know!:rolleyes:

Oneway touts a .005" runout or better so that seems to be a common theme.
I have to think that metal lathes are much more accurate and I'll assume that the majority of kitless threading I see posted here is done on a metal lathe.

I'm still not sure I'll get any better with a new lathe. Maybe the hardware will let me use my measuring tools to check the one on display before I buy it...ya think?:rolleyes:

I guess I'll have to use the other excuses for a new lathe, like a slower speed, indexing and reverse!
 
Levi, I had just yesterday read some mods using a DC motor and controller, neither of which I already have.
The total cost would be several hundred and I may as well buy the delta and save the trouble.
I was thinking in terms of a small gear motor with reverse that can be put into use as a secondary....but that's still just in my head!
 
I have a Jet 1642 and the runout on the inside of the spindle is less than .001", same for the spindle backplate. I consider this VERY good for a wood lathe, your .0015" is also very good...don't change anything!:biggrin:
 
Dale said:
I have to think that metal lathes are much more accurate and I'll assume that the majority of kitless threading I see posted here is done on a metal lathe.

!

A lot is done on wood lathes with taps and dies. The accuracy comes from drilling, tapping and turning the od in one set up. Same with id. Drill and turn and run die over. You can have a pretty sloppy set up as far as chucks go, but still get good results with the right process. (I have done this in shops with old equipment).
 
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