S7 leadscrew

[richard 2Participant @richard2]

Hi everyone

The leadscrew on my S7 is very difficult to turn making advancing of the carriage 0.001" very difficult.

The carriage moves smoothly and easily, everything is oiled (including my hands- courtesy of the Swiss made oilgun) but still no joy.

Does anyone have any suggestions, please?

What has happened to the Yahoo "Myford Groups" – I cannot get any joy there.

Regards and thanks to everyone.

Richard.

[richard 2Participant @richard2]

[John HaineParticipant @johnhaine32865]

I assume that you have disengaged the leadscrew from the spindle with the tumbler reverse? It will still be driving all the feedscrews, and in the "wrong" direction as the gearing from l/s to spindle is "up". If you just want to use the l/s handwheel for small movements, best to disengage the screw from the gear train by slackening off the banjo and sliding out of engagement.

[John HaineParticipant @johnhaine32865]

Posted by John Haine on 16/04/2016 15:36:54:

I assume that you have disengaged the leadscrew from the spindle with the tumbler reverse? It will still be driving all the feedscrews, and in the "wrong" direction as the gearing from l/s to spindle is "up". If you just want to use the l/s handwheel for small movements, best to disengage the screw from the gear train by slackening off the banjo and sliding out of engagement.

Apologies, I should have said "driving all the changegears"!

[Simon Williams 3Participant @simonwilliams3]

I'm just wondering if you have the half nut engagement adjustment set too deep. The half nuts have an adjustable stop by means of an allen screw and a spring, if this was allowing the half nuts to clamp down on the thread instead of just engaging it this might give you the symptoms you describe.

HTH Simon

Edited By Simon Williams 3 on 16/04/2016 17:07:21

[richard 2Participant @richard2]

Many thanks, everyone.

Went into the workshop and realised that, the vendor would have had the lead-screw off to shorten it.

So i managed to adjust the half-nuts (more or less by guesswork as I do not know how it should be done) as when I engaged them the lead-screw was even stiffer to turn; I loosened the nut on the lead-screw hand-wheel and tapped it slightly away from the bracket (using a short piece of ali rod and a plastic hammer) and it spun round with no stiffness at all.

So job done and the lathe is now lovely to use and I can move the carriage 0.0005" according to the DRO.

Many thanks to all you good people and I am off to the workshop to make a couple of 3/8" BSF screws.

Richard.

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