Newby machine help please

Hi I have looked and the manual again and I cannot see head or tail what Russell is talking about, Marc on looking at your photos what gears do you have ,

One small tip if you put the speed leavers in neutral with the motor running and pull the leaver to run the internal pump until oil runs through the sight glass top right this allows the headstock bearings to be lubricated you have a very good lathe

The gear highest up in the sequence will be linked directly to the spindle and probably rotate at the same 1:1 ratio with the spindle (check this). We can call it the spindle gear as if it were directly on there. The bottom gear should be the input to the gearbox

The gears are at a random position at the moment if I am getting the picture rotated right in my head. The 63 appears to be on the input to the gearbox ie a driven gear. It is never required in this position.

Imperial. The plate by the top left lever says eg "60,40,INT" and "40, 40, INT" the INT stands for "intermediate" and is just to bridge the gap between the other two gears so it will not change the ratio and can be any gear that fits.

The middle top plate shows you the threads you will get eg for third column 8,9,10,11,12,13,14 for each lever number setting BUT only if you have 40: INT 40 on the gears.
For the moment you are gong to have to put 40 on the 'spindle' and 60 on the gearbox with whatever fits, probably your 42 in the middle to bridge the gap.

This means you get threads which are finer than the plate by 60/40 eg 8 becomes 8x60/40 = 12

The table then becomes (should be 5 columns but can't paste properly from Excel)

      ac   bc   ad   bd

1    3     6    12     24

2     3.375 6.75 13.5 27

3     3.75  7.5  15    30

4     4.125 8.25 16.5 33

5     4.5    9     18        36

6     4.875 9.75 19.5 39

7     5.25 10.5  21     42

column on the left is lever position 1,2,3,4, etc

Edited By Bazyle on 11/02/2017 15:13:49

Edited By Bazyle on 11/02/2017 15:29:24

For the missing gears you can still get industrial gears from eg Devall but the hole in the middle and the keyway probably won't be as required. You need to know the 'Diametric Pitch' or DP. Take the 60 gear, measure the diameter over the teeth in inches, calculate (60+2)/(diameter). It will be a round figure like 12,14,16. If it is not a round figure it may be metric which we can tackle later.

Devall look under "spur gears inch"

You will be able to sort out the hole size and keyway on your lathe after a bit of practice. COme back for advice when needed.

If you look at the table of metric feeds in the second picture in his album the pitches I quoted are the only ones that use the gear combination he said he has. Simple

Russell.

Thank you very much gentlemen, I really appreciate all your help.

Cheers

Marc

Marc after checking on the lathe between the two leavers you will see it says threads per inch this means you can cut imperial threads 2 to 28 as long as you have gears 44 driver 44 driven with no other change you will need change wheels for metric threads for imperial threads on this chart I e leaver 1 leaver AC will give you 2 tpi leaver 5 leaver AD will give you 12 tpi hope this makes sorry I don't have any photos

Cheers scrumpy.

Ok, the OD over the teeth of the 60 is 5.647" or 143mm so am I correct in thinking 62/5.647? As that doesn't really match any size gear in davall. I can't see it matching any metric size either, any ideas?

That looks like 11 DP which is a bit unusual, even numbers being more common.

Russell

Hi Marc iv'e got a Mitchell there should be 12 gears in total one each of 30, 42, 44, 45, 46, 48, 57, 60, 63, 80 and two of 40, if you need a copy of the manual I can photocopy it for you regards frank

Hi Marc, don't know if this is any help to you, but it looks like you have this model.

Regards Nick.

Edited By Nicholas Farr on 09/12/2019 08:51:54

This thread is nearly 3 years old. I doubt Marc is still following this.

Thanks gents, I’ve still got the lathe but haven’t used it much. I’d be very interested in a copy of the manual if you could though please?

marc

Two comments Sorry to be depressive.

To calculate the DP of the gears.

OD = (N+2 ) / DP So, for the 60T: 62 / 5.647 = 10.979. Which, as Russel said looks like 11DP. An odd number in both ways!

Since the dimensions form the lathe are all quoted in Imperial, I think that we can discount the gears as being Module types Plus the 6oT with an OD of 143mm would be a 2.3 module, which seems to be even more odd.

May I suggest rechecking the tooth count and the OD, in case the gear is actually a more normal DP?

If a complete set contains 12 change gears, and you have only 3, buying the remaining 9 is going to be expensive. Possibly as much, or even more, than you paid for the lathe. And then, IF they are correct width, they will need to be modified to provide the correct bore and to cut the keyway.

My suggestion would be to see if you can find a Model Engineering Society close by, with a kind member who would be prepared to buy cutters, (more than one is likely to be needed, probably three without checking, so you are looking at £60 -70 as a starting point ) and to cut you as set of gears,

Either way, whether or not the gears are a strange DP, it is going to cost a bit!

Howard

.

Wise advice, Howard

Although I would hope that a gear so boldly marked 60 would have 60 teeth; mistakes do happen.

**LINK**

https://www.model-engineer.co.uk/albums/member_photo.asp?a=43830&p=723467

MichaelG.

Edited By Michael Gilligan on 09/12/2019 21:01:32