Taig lathe gets power feed

Spent yesterday afternoon installing the latest version of the Taig lathe - there are various improvements that have been made over the years, but the most significant one is the addition of a rather neat saddle power feed system. There's a gearbox attached to the headstock which is driven from the spindle pulley, giving 3 different feed rates

- the finest gives a really fine cut but even the coarse setting gives a good finish.

The neat part of it is how the feed is engaged; the old rack and pinion saddle traverse has been replaced by a leadscrew attached to the output of the gearbox, and this engages a worm gear that is attached to the saddle traverse handwheel. As the leadscrew rotates, the handwheel freewheels, and the saddle stays put; if you grab the handwheel to stop it ritating, the saddle moves, and stops moving as soon as you release the handwheel. This arrangement also allows "normal" saddle traverse by cranking the handle, without having to switch off the power feed.

The drive from the spindle pulley uses an ordinary elastic band; if you want to reverse the drive, you simply put a half twist in the band.

Works remarkably well.

Regards, Tony

Reply to
Tony Jeffree
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Tony,

I'm having difficulty visualising this 'leadscrew engaging a worm gear' and yet surely needing to provide a 90 degree drive to the saddle handwheel. The taig website pictures don't help either.

I could understand a pinion meshing with the leadscrew in place of the rack to give the effect you describe.

Sound an interesting scheme though.

Bob

Reply to
Bob Minchin

That is in effect what it is - but it is a worm gear rather than a pinion (the teeth are angled at the helix angle of the leadscrew). The worm gear is attached to the handwheel shaft.

Regards, Tony

Reply to
Tony Jeffree

OK the teeth on the gear are at a small angle to the axis of rotation. Whether that make it a worm or helical pinion is debatable. I think of a worm as being much closer to a thread than a pinion. Not sure of the text book definition. I however understand what you mean. Thanks for the clarification.

Bob

Reply to
Bob Minchin

The worm in this case is the leadscrew (which is of course a thread). I was referring to the worm gear (which isn't a thread). Maybe I should have called it a worm wheel for clarity. In this case it really is a worm wheel rather than a helical pinion; if you look at the teeth along the axis of the worm, they are concave, i.e., the teeth wrap around the worm.

In reality the gear wheel is being used in two ways - as a worm wheel (when the leadscrew is rotated) and as a pinion (when you rotate the handwheel by hand). Similarly the leascrew could be considered to be a worm or a helical rack, depending on your point of view.

Regards, Tony

Reply to
Tony Jeffree

I just found this post and have a question about the leadscrew. I have

48" version of this lathe made for doing pool cue repair and building and would like to add this powerfeed set-up, but will need a longer leadscrew and was wondering what the thread is before I get the gearbox.
Reply to
flyingluthier

Call the Taig factory - I'm sure they will be able to tell you. They may also be prepared to make you a conversion kit with a longer screw.

I will measure the screw on mine when I get back at the weekend.

Regards, Tony

Reply to
Tony Jeffree

It is a 10 TPI screw.

Regards, Tony

Reply to
Tony Jeffree

Is that a standard 60 degree thread; or something fancy like an acme thread?

Reply to
flyingluthier

Looks like ACME to me.

Regards, Tony

Reply to
Tony Jeffree

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