Myford ml2/3 change gears

[barryParticipant @barry]

Hello, I have recently printed a 20/60, 20/65 and 20/60 for my Myford ML2/3 as seem in the picture below from the advice of Howard Lewis post from a few years ago. It dfoes not give a fine feed, looks more like a screw cutting. Any ideas on how to get a fine feed to work. It has not got the reverse lever on it.

 

On 8 February 2023 at 11:41 Howard Lewis Said:
The edarly Myfords were distinguished by the centre height and centre distance.

the ML 1 was 3.125 centre height, and was 15″ centres,, from memory (Dheck with Lathes UK )

The ML3 was 3.5″ centre height, 15″ centres, and the Ml4 was, like the ML2 a greater centre distance.

The thread for the chucl, originally was 7/8 BSW, (7/8 x 9 tpi ) but later was changed to 7/8 x 12 tpi.

Possibly, some of the very last were 1 1/8 x 12 tpi, but lacked the 1 1/4″ register used on nthe ML7

A peculiarity is that there is no gear in the Saddle so that moves the opposite way to the handle rotation.

i.e..Clockwise rotation of the handle moves towards the Headstock

The gears ar 20 DP, 14.5 PA but are driven, (by driving collars on the spindle and Leadscrew ) or compounded by 3/32 pins, rather than the keys used on the ML7.

The bore and width of 7 Series gears is the same, so by drilling through an existing gear, it can be used as jig to drill a 7 Series gear for use on the earlier Mls.

But try not to drill right through, so that the opin is retained.

Threads will be 1/4 BSF , mostly with a few BSW included. The gib screws ar probably BA.

For full details, look at lathes UK pages on the Ml1, 2, 3 and 4.

It may be ols, but if in reasonable trim is quite useabl.

It bmight be nworth getting an extra 20T or two, so that a fine feed can be set up 20:60/20:65/20:60 on the Leadscrew. This should give a fine feed of abouyt 0.004″ per rev. Yiou may need to fettle the spindle end of the banjo. to allow the stud to give good gear mesh.

The Tailstock barrel is prevented from rotating by a 1/4 BSF grubscrew with a key in the end that engages the keyway in the barrel. Once adjusted, it is secured by a locknut.

It might well be worth making an adaptor so that the later 1.125 / 1.25 register “standard” Myford fitting chucks can be fitted. I did this for somone who acquired a ML4, which we eventually got sorted and useable.

HTH

Howard

[JasonBModerator @jasonb]

Take the 20T off the lead screw as it looks like you have that meshing with the 65T. You want the 20T behind the 65T to mesh with the 60T on the leadscrew. It should be small gear driving a large one on all studs and leadscrew.

so that a fine feed can be set up 20:60/20:65/20:60 on the Leadscrew.

From Howards post

20:60 = 20T on spindle drives 60T plastic 1 /

20:65 = 20T plastic 1 drives 65T Plastic 2/

20:60 = 20T plastic 2 Drives 60T on Plastic 3

No need for the last 20T on Plastic 3

[SillyOldDufferModerator @sillyoldduffer]

I suspect the gears aren’t set correctly. They should all go from a low toothed driver to a high toothed driven.  In the picture:

Red A is good

Red B is good

Red C! looks wrong: big wheel B drives a small wheel, so the ratio isn’t geared down.  The small C wheel should be behind big wheel B and mesh with big wheel C (which is correctly positioned.)

Hope that makes sense.

Dave

 

[barryParticipant @barry]

Thanks for the quick replies. Have done what you suggested. They all mesh together now but I cannot fasten the lead screw gear. The gear B is now touching the lead screw shaft.

Thanks

[Howard LewisParticipant @howardlewis46836]

I fear the you have made a gear with too many teeth, or put it in the wrong position.

You need another stage of reduction.

The set up that I made for a newbie, (A LONG time ago, so relying in memory)  with a ML4 was;

20 tooth driver to 60T /20T compound to drive a second compound 65/20, which drove the 60T on the Leadscrew .

In this way the first 20:60 does not clash with the second 20:60 and the overall reduction becomes 29.25:1 giving a  feed of 0.00473″/rev, which should provide a fairly fine feed..

Thinking back, this meant making up an extra stud (and had to fettle the slot in the banjo to incorporate the extra stud for the extra 20T and 60T)

The extra 60T was from a ML7, so had to be drilled for the 3/32 pin which connects the compounds together

It can be done!

Howard

 

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