Boxford AUD gearbox

[Tim Green 1Participant @timgreen1]

Good morning all,

Some background for you. Restored a couple of prewar cars but lacking any lathe skills so bought an old Boxford AUD as I thought it would come in handy. Motor worn out so replaced with new 1.5hp electric motor and so far so good. Now time to try the lathe. Made myself familiar with the basic functions and thought I would try to cut a screw thread using the gearbox. I Chose a 22tpi thread at random. Gearbox instructions shows that I should engage the right hand gear knob in the hole that lines up with the number 22 and the left hand gear knob on hole B. I give it a couple of dry runs with no work piece and sure enough the apron(?) travels left and right as instructed as the chuck turns. Now I secure a piece of 10mm brass round bar in the chuck and cut the thread. I produce what I can only describe as a lovely 122tpi thread, a bit finer than I had hoped for. What I am doing wrong? Also, while we are at it, despite the new motor I feel that the operation of the lathe is a bit laboured so comments on that subject would be welcome. Please bear in mind that I know NOTHING about using a lathe so please do not assume I will know what all the parts, functions and terms are. Many thanks, Tim

[Tim Green 1Participant @timgreen1]

creating wrong thread

[davidkParticipant @davidk]

Hi Tim

For lots of information on Boxford machines, you could try joining the Boxford Yahoo Group. **LINK**

I'm a member myself, they're a very helpful and friendly bunch of guys.

Regards

David

[Speedy Builder5Participant @speedybuilder5]

 

You are not too far off, but there is another crucial piece of information on the gearbox plate. You should have a 20 Tooth gear on the "STUD" (That is the removable gear on the direction selector) and 56 Tooth gear on the Screw Gear (Gearbox input shaft). In between these gears there has to be an 'Idler' gear of any size that makes the afore mentioned gears mesh together. This will probably be about 80T. Make sure the Stud gear and the Screw gear are keyed to their respective shafts.
Have a look at this web site – probably not the AUD, but is interesting reading.

**LINK**

Its different from my copy which was an original (some time ago) – I will try to find an AUD link.

Good luck BobH

ps If this info doesn't help, there is a possibility that your machine was fitted with the Metric leadscrew (even though it appears to be an Imperial lathe) – see on this site.

 

Edited By Speedy Builder5 on 22/02/2015 13:49:05

[Bob Brown 1Participant @bobbrown1]

Mine is metric so the gears are different but the gears for imperial should be 20 top 80 idler and 56 on gear box input.

There should be a chart on the gearbox that shows the gears required for any given thread pitch.

If you PM your email address I can send you a Boxford book which should help.

Bob B

[Bob Brown 1Participant @bobbrown1]

This may help **LINK**

"lathe is a bit laboured" may be a slipping belt on the drive to the spindle.

Bob

[BazyleParticipant @bazyle]

Don't forget to lubricate the backgear layshaft and the main spindle pulley sheave when you are running back gear. Slacken the belts and disengage the both the layshaft and bull wheel and see if it all turns freely.

22 to 122 seems a huge difference, it would take a couple of extra gears in the chain to achieve this. Just to be sure you were using the screwcutting half nuts operated by the lever on the right of the apron? When not screwcutting and using the feed do you understand the operation of the star wheel on the front of the apron? It's all in the book.

BTW if you ever take the star wheel off the apron for a strip down remember that screw in the centre of it is a LEFT HAND THREAD ie reverse. 90% are broken by people not realising this and it's not in the book.

Edited By Bazyle on 22/02/2015 23:02:56

[Bob Brown 1Participant @bobbrown1]

Posted by Bazyle on 22/02/2015 22:36:58:

BTW if you ever take the star wheel off the apron for a strip down remember that screw in the centre of it is a RIGHT HAND THREAD ie reverse. 90% are broken by people not realising this and it's not in the book.

Should that not read left hand as right hand is the normal direction?

[BazyleParticipant @bazyle]

Yes, brain fade. I was thinking to write it differently and go tin a muddle.

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