C0630 Lathe Restoration Shanghai 11th machine works
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Re: C0630 Lathe Restoration Shanghai 11th machine works
If you want a CNC lathe you will be time and money ahead to just buy one to start with !!
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Re: C0630 Lathe Restoration Shanghai 11th machine works
That doesn't surprise me. That the spindle has runout doesn't necessarily mean the bearing isn't inscribing a circle. It might be difficult to determine why you're getting that small amount of runout, however, and I agree with you---it shouldn't be there.armscor 1 wrote: ↑Mon May 02, 2022 5:59 am Hi Harold, you say roundness is a function of the headstock bearings.
My lathe has 8/10 of a thou runout measured in the spindle taper and on the D1, 4 external taper.
I took a very light cut on a piece of 2" aluminium bar and measured at different locations on the circumference and measured with a tenth resolution micrometer and no deviation.
I'd certainly entertain any or all of those options. A bent spindle should be easy to identify---simply check the vertical surface of the D spindle for runout (the face on which the chuck bears). If there is any deviation, certainly a bent spindle would be suspected.Can I assume the spindle is not machined true or not seating true on the inner race of the bearing or worse the spindle is bent?
Mixed emotions. If the machine is yielding round parts, none of the above is important. It's like gripping a piece with a three jaw with runout. The work performed will be correct---but it won't relate to the portion that is gripped (you'd have an issue with concentricity between those two features). If the machine is serving your needs and the relationship between the machining and the gripped portion is acceptable, I'd say leave things alone. I'd have a different view if the resulting work was not round.I think the course of action is to replace the bearings and grind the spindle true if required.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: C0630 Lathe Restoration Shanghai 11th machine works
Thanks Harold, I like the idea of leaving things alone!
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Re: C0630 Lathe Restoration Shanghai 11th machine works
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Re: C0630 Lathe Restoration Shanghai 11th machine works
More photos belowBill Shields wrote: ↑Mon May 02, 2022 9:22 am QUESTION:
are you sure you have room inside the cross slide /compound for ball screw nuts?
Typically they are larger in diameter than conventional 'nuts'
we have an expression in North America involving silk purses and sow's ears.
The ball screw nut might just fit in with some grinding of the ballscrew mount, the gap measures 28x40mm
Re: C0630 Lathe Restoration Shanghai 11th machine works
I've ordered new starter caps for the motor, but i think i'll have to take it apart first to check out the windings coz the copper wires coming out of it are old and crusty. Not sure why 120v caps are installed when 230 V 50 Hz here in singapore
Re: C0630 Lathe Restoration Shanghai 11th machine works
Nah im a poor college kid with a few stepper motors on hand and access to cheap chinese sparts.John Evans wrote: ↑Mon May 02, 2022 1:13 pm If you want a CNC lathe you will be time and money ahead to just buy one to start with !!
Re: C0630 Lathe Restoration Shanghai 11th machine works
I think the 1204 ball screw, 12mm diameter 4mm pitch will fit if i grind 2mm off the H dimension.Bill Shields wrote: ↑Mon May 02, 2022 9:22 am QUESTION:
are you sure you have room inside the cross slide /compound for ball screw nuts?
Typically they are larger in diameter than conventional 'nuts'
we have an expression in North America involving silk purses and sow's ears.
Smaller ball screws will definiately fit, but i want to stay close to the original 13mm T13 lead screw size
Theres 0802, 8mm pitch 2mm lead
1002, 10mm pitch 2mm lead