Myford and Boxford changegears question

Sorry no. Myford gears are 20 DP, Boxford are 18 DP Translated into English that means a Myford worm is 6.36 TPI and a Boxford is courser at 5.73 TPI.

A gear train to cut a Boxford worm consists of a 55 driving a 35 coupled to a 40 driving a 45.

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Thanks ! I guess that rules out using the Hemmingway headstock dividing head attachment on my Boxford unless I bored out a Myford 60T changegear to fit.

Cheers,

David

Not at all, just alter the design to accept a 18DP worm. Fitting a Myford 60 T wheel will render your backgear useless unless you had thought about mounting all this outboard of the spindle?

-- Regards,

John Stevenson Nottingham, England.

Visit the new Model Engineering adverts page at:-

Yep - I was just going to fit it in place of the main gear drive instead of the normal first gear. Shouldn't be a problem as You'd obviously never need the gear train at the same time as you do headstock dividing.

The problem with re-designing it is it's part and parcel of the Hemmingway VDH and if I change that worm I'll need to change the design of some other bits of the VDH too. Not that that might not be a bad idea given I could make it a better size match for the Boxford at the same time, but it's growing from a simple kit build to a design-it-as-well effort and then I'd also need to make my own worms instead of just buying them ;-)

I may still consider this though - I've just got hold of a copy of Alibre Xpress and it might be a nice first design...

Thanks for your answers,

David

Not necessarily the case that the change gears are the same pitch as the bullwheel/back-gear train - ceartainly Myford use a different pitch for the bullwheel/back gears on the ML7 from those on the Super

1. ML7 (and ML10) have a 20DP bullwheel; the Super 7 bullwheel is 16DP (according to the worm specs in the George Thomas book).

Worth checking what the Boxford bull wheel pitch actually is - you might find that the Super 7 worm fits.

Regards, Tony

Good point but don't know how convenient it is to get at the Boxford bullwheel - it's hidden under the headstock casing and the only plausible access point is that small rectangular plate on top. My original idea was to mount the HDA on the banjo at the rear, this still seems easiest to me.

David