What’s the purpose of the hole in the Zyto lathe’s headstock pulley?

[David Jenkins 4Participant @davidjenkins4]

I'm in the process of renovating my Zyto 3 3/8" lathe headstock, and I'm a little puzzled…

The smallest of the three flat-belt pulleys at the headstock end has a small threaded hole, and I can't see what it's used for. The only possible use I can think of is for getting oil into the inner bearing surface of the pulley, where it spins on the outside of the spindle. It can't be used for fixing the pulley, as that would defeat the operation of the pulley and back-gears!

Is it as simple as that, or have I missed something?

[David Jenkins 4Participant @davidjenkins4]

[HopperParticipant @hopper]

If it is the same as my old M-Type Drummond of the same era, you are correct. There is a small grub screw on one of the flat belt pulleys, on the surface the belt runs on. You take the screw out, add oil and put the screw back in before using the backgear. This lubricates the pulley spinning on the spindle as backgears do their thing.

Be sure though NOT to screw the screw all the way in or it will score the spindle and the swarf from that abrades the spindle and pulley bearing surfaces. My poor old M-Type has suffered this indignity and the pulley is a loose fit on the spindle as a result, making for a noisy backgear train. The screw should go in only far enough to be below the belt surface. A bit of teflon plumbers tape on the thread helps keep the oil in and secures the screw to some extent.

[Ady1Participant @ady1]

As Hopper says. oil hole

[David Jenkins 4Participant @davidjenkins4]

Many thanks!

I thought that's what it was – I was confused as I was given a headstock pulley from a different lathe, and that has a recess under the screw where the backgear driving wheel is fitted. My gear is part of the pulley.

Good tip about teflon tape – I'll bear that in mind on re-assembly.

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