Lathe jumps out of gear

[noel shelleyParticipant @noelshelley55608]

I've come late to the party but the pic of the dimples in the head show noticeable signs of wear and could well lift the ball out of the detente and stop the train. Hard balls on a soft iron casting ? Poor tooth contact due to a failure to fully engage won't help. Noel.

[Dave HalfordParticipant @davehalford22513]

Are both the layshaft bearings still good?

It's hard to see why a gear should start drifting when the gear lever has hardly been moved in 20 years even if the detents are a bit 'off'.

[BazyleParticipant @bazyle]

Good grief! 3 days and this trivial problem not fixed. You are as bad as me. I often say it takes me an hour to boil a 3 minute egg (HSE warning the recommendations are probably an hour boiling now to avoid listeria).
Just move the lever vertical, re-drill the roll pin hole, choose a single detent and make 3 new dimples in the clear area.

I suspect the designer's original intention (on the German designed lathe they copied) was to have 2 detents holding the mid position to give a very firm hold when the compound gear is out of mesh to avoid it being accidentally nudged when running and grinding the gears. Some twat in the Chinese drawing office also started with the left hand hole and then found the right hand hole clashed with the lever so shifted it a bit instead of redrawing the first hole. The manufacturing process involved a bloke on piece rate with a pistol drill who didn't care if the detents were misaligned.

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