Myford headstock bearings

I have a lot of experience with machines but I am a newcomer to Myford lathes. This is my experience with a newly aquired Super 7.

Because it was quite marked up I put a new gear on the end of the headstock spindle and turned the collar against the inner race, by hand, to set the play in the bearings but noticed that the end-play had now also gone between the pulley and the steel gear on the spindle and the backgear lever had become impossible to turn and lock.

I then tried to undoing the grub screw on the steel gear to see if I could move the gear to create more end-play without success so I resorted to backing the collar off a fraction which restored the end-play in these components.

To my mind the end-play between the pulley and steel gear on the spindle should be independent of the bearing adjustment, so I have studied the cross section drawings of the headstock in the manual which doesn't show a key under the steel gear but does show a line which I take to be a shoulder on the shaft.

My current guess is I might not be applying enough force to move the gear along the shaft but I don't like levering things without prior knowledge of their design.

Any thoughts on this matter will be appreciated.

No end-play in the pulley/backgear solved !

On taking the spindle out and putting the backgear and pulley back on it I found there is a gap between the bush and the last shoulder on the shaft (and not the other way round) the reason being the gear on the other side of the pulley has either crept out in use or has not been pressed fully home on fitting.

I am them tempted to pull the gear out and re-fit it with some Loctite 641.

Edited By C J on 15/03/2018 00:25:20

Pulled

Back together, but what should I expect?

Edited By C J on 15/03/2018 03:04:38

I think that you need to be checking the taper and not the chuck body as this may not be true with the register on the backplate.

Frank

Ooops! 😳 It could look like I’m checking for runout but I would have set the gauge differently.

My fault, I should have said “what should I expect in lateral movement once the spindle is set” as I haven’t adjusted the bearing locking rings yet and I’m getting some movement on the gauge when I push and pull on the chuck without turning it.

Can there really be no movement?

In the meantime searching for a narrow C spanner.

Edited By C J on 15/03/2018 07:32:18

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Edited By C J on 15/03/2018 07:59:15