BA and MOD D.P. change wheels for boxford IS11.30 (modern type) lathe

[stvy]

Hi,

I have a boxford is11.30 lathe that I have been refurbishing. I have the 9 standard change wheels which came with the lathe. On a whim I got in touch with Boxford to enquire about the cost of buying the missing change wheels for thread cutting.

According to their website:

http://www.boxford.co.uk/products/man-machines/lathes/

with 4 additional wheels I can cut 0 - 8 BA threads.

with 2 additional wheels and an aux changewheel stud I can cut .3-2 MOD, and 14-60 DP.

However it turns out that they are no longer for sale. Furthermore boxford would give me no details such that I can cut my own to spec.

Does anyone have any idea of the spec? Or could point me in the right direction?

Thanks,

Steve

[vtsteam]

Well that's not very nice of them.

I'm sure we could figure it out.

What are the gears you have?

[chipenter]

Have you tried Tony @ lathes http://www.lathes.co.uk/page8.html they manufacture parts ans have second hand tools .

[stvy]

Hi,

Well I have the set of 9 change wheels for metric and imperial standards thread cutting. This set of 9 changewheels: ( 39 metric pitches 0.2 - 7mm) (34 English pitches 3.5 - 128 TPI

The gears have 60 57 56 54 52 46 45 44 42  teeth

According to the manual there are also 96, 72, 70, 66, 48, 40, 39, 38 teeth gears listed in the gearbox pages. However the manual I have (from tony @ lathes.co.uk) provides no information on what is what. Its just a list of numbers.

The only other information I have so far is that for the BA 0-8 thread cutting you could order 4 additional wheels. For hte MOD and D.P. 2 additional and an aux change wheel stud.

That is all the information I have so far. I am just at the beginning...

I will give tony at lathes.co.uk a call and ask him if he knows more.


Thanks,
Steve

[stvy]

Hi,

well a little more research on the gears I have. Assuming a reasonable approximation (gear teeth might be undersize):

D.P == number of teeth + 2 / whole (outside) diameter in inches

for 3 example gears yielded  a DP of 25.41, 25.43, 25.44. As there are 25.4mm in 1 inch, then a number 1 module is equal to 25.4 DP.  I think it might be safe to say that these gears are 1 mod.

Thanks,
Steve

[hopefuldave]

Not sure how much (if at all) this will help, but for.cutting DP worms the pitch will be Pi divided by the DP of the wheel it's for - so you need a factor of Pi (or as close as you can get) in the changewheel train, same with module, mm pitch will be Pi times the module.

If you don't need utmost accuracy (eg a worm for a dividing / indexing attachment where backlash isn't critical), metric pitches can be close approximations to DP pitches, tpi close for module, eg for a worm to fit a 16 DP gear/wheel, the exact pitch converted to mm is 4.987mm, 1Mod comes out as 0.1236" pitch, so 5mm and 8tpi are close enough for government work!