Myford Super 7

[Tom GullanParticipant @tomgullan59234]

Back Gear

[Tom GullanParticipant @tomgullan59234]

Hello,

I have a problem with my Myford Super 7 lathe. I'm new to model engineering and have recently learnt how to cut threads using my lathe. This afternoon I engaged the back gear and started to cut a thread. When I switched on the power the spindle/chuck jerked rather that turned. It appears to be seized. When I disengage the back gear lever the internal gears rotate freely. Can anyone help with this problem?

[BazyleParticipant @bazyle]

Never played with a Myford but lots of lathes have a lever AND a pin to pull from the bull wheel (the big gear).

[Tom GullanParticipant @tomgullan59234]

Bazyle,

I've done that, the pin has been rotated and the back gear is engaged properly.

[BazyleParticipant @bazyle]

When you say the internal gears rotate do you mean the ones on the layshaft under the main spindle?

So with the pin pulled out and the lever disengaging the back gear cluster (layshaft gears) does the pulley cone rotate freely without the spindle moving – exccept for a bit of drag?

[Tom GullanParticipant @tomgullan59234]

Bazyle,

yes, the large gear which lifts up when you move the back gear lever rotates freely when the lever is in the down position.

With the pin out ( disengaged) and the back lever in the down position (disengaged) the pulley cone rotates and so dies the chuck.

[BazyleParticipant @bazyle]

There is a parts diagram at the bottom of this page. in case that helps. You can see why the lever on the bull wheel has to be turned a full 180 degrees.

"pulley cone rotates and so does the chuck." but not together I hope you mean. I think we had a problem reported once where the detent spring wasn't working and the lever swung back into engagement owing to centrifugal force.

[davebParticipant @daveb17630]

It sounds as if the pulley sleeve is seizing on the spindle. Lubricate and try again.

[Russ BParticipant @russb]

As per the last 2 comments, the 4 step belt pulley should rotate freely from the bull wheel when the little lever is disengaged (the bull wheel should be at one with the spindle – it is keyed).

A few paragraphs out of curiosity, apologies if I'm telling you how to suck eggs!

When was the last time you gave all the oil nipples a hit with a push type oil gun – specifically the one in the back of the 4 cone pulley! (Wanner or Tecalemit push gun for example) –

Also have you read the manual?

The manual covers all aspects of setting up the machine for first use, from initial levelling which is critical to the machines accuracy, to adjustment of the spindles front and rear bearings which is absolutely critical to its health. It also sets out all the oil nipples and points as well as how frequently they should be oiled – the spindles front bearing on mine I think quotes one drop every 10 minutes – its not like a car, you can't service it every 6/12 months and hope for the best!

You can find the manual on google if you don't have it, and I can supplement you with the removed/replaced pages for the "old" style clutch and spindle lube system if you need it.

Again, eggs, apologies……..

[Ian S CParticipant @iansc]

The pulleys seized on the shaft of my 1326BH Taiwanese lathe through lack of lubrication, that was 20 years ago, I found the oil hole, and since then no trouble. (the oil hole is not indicated in my handbook).

Ian S C

[Tom GullanParticipant @tomgullan59234]

Gentlemen,

Thank you very much for your input. I ended up removing the headstock spindle and greasing up the gears, pulley and spindle. It now works fine. I now have a manual, I didn't realise that the lathe required so much attention.

Regards

Tom

[DMRParticipant @dmr]

Tom,

Only just discovered your posting. Taking your wording, and bearing in mind you say you now have the manual.

None of the "grease nipples" on a Myford are for the application of grease. Nothing thicker than thin car engine oil. The amount of attention needed depends on use. If you only use backgear once a month, then apply a squirt of oil to the nipple in the spindle pulley once a month (before use). Same logic for all of the machine.

Dennis

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