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BOXFORD IMPERIAL DIAL

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fishy-steve:
Hi Griffin,
I've just read this thread and must admit I'm  a little confused. From what I understand you think that by changing the cross feed dials from metric to imperial will give you  satisfactory and accurate movement in imperial units?

I've reread Tonys write up on lathes.co.uk concerning the lathes that were partially converted from imperial to metric for educational use during the early  metrication years. From what I understand, the leadscrew remained  8tpi but a metric conversion set of gears were added to the headstock. The imperial gearbox remained. This meant that metric threads could be cut if needed if reference  was made to the correct chart.
You believe that the dials on the cross feed and compound slide were changed to metric but the screws and nuts were left imperial.
That sound like a real fudge.
I made the assumption that the screws and nuts in the cross and compound were changed to 2.5mm pitch instead of 10tpi.
My Boxford AUD is full metric so I have no idea if that is the case.
Could you just put some scrap up and take a light cleaning cut. Zero the dial. Take a measurement with a metric mic. Take a few roughing cuts that amount to just under 3 turns of the cross feed dial (3 turns will amplify the potential  error) then take a light finishing cut. Measure what your left with.
I would be really interested in the result. It would solve my confusion  if nothing else.

All the best.
Steve.

John Stevenson:
I'll bet Griffin wishes he hadn't bothered now.
Half of these repiles could have been cut out IF they had read the OP correctly  :Doh:

RobWilson:

--- Quote from: John Stevenson on March 28, 2016, 09:30:02 AM ---I'll bet Griffin wishes he hadn't bothered now.
Half of these repiles could have been cut out IF they had read the OP correctly  :Doh:

--- End quote ---

Did you John  :scratch:


--- Quote ---When I recently took delivery of my imperial long bed Boxford AUD MKII, I was very slightly disappointed by the fact that it had metric dials fited. I was told by the previous owner that it had originally been a school lathe and they had probably fitted them  post metrication. I couldn't help thinking that this was a little silly as the machine had an imperial thread cutting gearbox but decided to change them for imperial ones anyway.
--- End quote ---

the Op has not even checked the pitch of the leadscrew   :palm:


--- Quote ---Having said that, I will check all screws and gears before I trust it enough to cut any threads.
--- End quote ---



OK !  I have a Metric Boxford AUD  , yes the gear box is imperial , this dose not make it an imperial lathe .




So just to prove things a wee test that the dials and LEADSCREWS are metric 


2.5mm per rev dial



ON ZERO


DTI ON ZERO !



One full turn ,,,,,,,,,,,,,,,hey WTF!  it reads exactly , not plus or minus a fannys hair  ,but bang on 2.5mm



mmmmmmmmmmm lets press the imp /metric button 




2.5/25.4 = 0.0984" ,thats a 0.003" error on a part OD/ID  with just ONE full rotation of the leadscrew if it were fit with an imperial 100 thou per rev dial  :palm:


Boxford did not fit metric dials to an imperial leadscrew  :bang:   


Rob

RobWilson:
PS , my lathe is also from a school



Rob

GRIFFIN:
:update:
Ok the moment we've all waited for, I've fitted a dial gauge into the tool post and as instructed dialled in three full turns on the cross slide !!! Hands in the air' it was 5 thou under three hundred thou, so I was wrong, it has got metric cross slide and compound screws. Looks like it's humble pie for dinner this evening for me!!!
:bugeye:
Please don't be too hard on me though, everything else is imperial, I have checked, 8tpi lead screw, imperial end gear set up, imperial gearbox, imperial name plate, HONEST.

The only question now: does anyone have a set of imperial screws and nuts for a Boxford AUD to convert it back to a full imperial machine?
:doh:

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