Myford super 7B Chuck threads

the one with peg on is a catch plate used specifically for turning between centres - likely will be tight because they are not used often (mine is and needs wringing on with lots of oil!). Should be left as is rather than turned into a chuck backplate.

Suggest you check your spindle for burs flats etc if the catch plate is really getting hung up as opposed to tight - should go on as it looks like Myford type

The Large undrilled one is no good as it has a nose on the front which has the threads

Difficult to see or assess dimensions but if the thread is 1 1/8 in and of correct 12W form, you can clamp it to the face plate and bore out the register in the 'nose; section to 1 1/4 in to fit the lathe spindle to make usable.

I don't know if the backplate in the third picture from top between faceplate and catch plate is the 'large undrilled one' or just the one plate that you say fits.

items bottom right are  lathe dogs for use with the catch plate when turning between centres'

the backplate that you say is too big for the chuck actually requires machining to the correct size with the correct register to fit your chuck

If you want another backplate, I would advise a new one from the usual sources rather than a used one (unless you can view and check over yourself). It will come as a threaded blank which you will have to machine to fit you chuck.

Google  'The Amateur's Lathe' by  L Sparey on amazon and get a copy - you will find it very useful.

Edited By Martin of Wick on 03/01/2020 09:55:24

Edited By Martin of Wick on 03/01/2020 09:56:14

The large one with the nose on front is probably for mounting a chuck on a rotary table and I use a thread chaser to clean gunge from my chucks

The items bottom right are driving dogs ( ? ) for turning between centres

Roy

Edited By roy entwistle on 03/01/2020 10:05:38

large one with the nose on front is probably for mounting a chuck on a rotary table

why? wouldn't you just bolt a chuck directly to the slots on the rotary table?

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They are driving dogs for use with the catchplate

... not the common style, but functionally similar.

MichaelG.

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Roy beat me to it ... I was responding to page 1 

Edited By Michael Gilligan on 03/01/2020 10:20:36

Did a bit of "Googling" apparently they are carriers for a grinding machine but no reason why they couldn't be pressed into service as drive dogs on the lathe.

John

The 4-jaw chuck appears to have an adapter plate fitted. I'd remove that to reduce the overhang and fit a backplate directly to the chuck.

Martin of Wick

By using this mount on the rotary table,you would be able to interchange the chuck, complete with job, between the lathe and the rotary table if you needed to

Roy

It's worth being aware that the late ML4 had the same thread as the ML7 but the register diameter was 1⅛ " not 1¼" , so face plates and such exist with the smaller register which would need boring out before fitting to a ML7. I know, I have one on the list of things to do...

Swarf, mostly, thanks for the tip about pinning the character map to the task bar. Done it!

George

Many thanks for all the input received. Its Rufforth on Sat so going to look for a tap. Not that i'm stuck for the 4 jaw. Would just be nice for it to done ready.

You will find a 4 Jaw extremely useful. With it you can centre work much more accurately than in a 3 jaw, offset it if you want to produce something with a known eccentricity. You will need a DTI or a Finger Clock for this, with a suitable base, (probably a magnetic one ). These will be useful for many other tasks, in the future, so a good investment.

If it were me, machining and fitting a Backplate for the 4 Jaw would be high on my list of priorities.

Howard

Thank you for the fractions idea. But I am on a Mac and not a PC. If it helps others, I have discovered [ctrl][cmd][space] brings up a character map for the Mac and search 'fraction' (singular) gives a few.

Question is, do my two dimensions read correctly on other people's computers? 1⅛", 7½".

Norm

Edited By norm norton on 03/01/2020 15:53:51

Good News, Norm. They do on W7

Howard

& on W10

They certainly look very professional ,much better than 1 1/8" . Oh & thanks again. 1 1/8" 12 tpi

If you came across one, it is possible that a Backplate intended for a ML 1, 2, 3 or 4 may be able to be modified. The original M Series used 7/8 BSW (9 tpi ) thread and 7/8 register. Slightly later the 7/8 thread was changed to 12 tpi, and only the very late M series used what is now known to as the "Myford " thread of 1 1/8 x 12 tpi

The 1947 ML7 introduced the 1 1/8 x 12 tpi with 1 1/4 register, that we now take as the Myford Standard.

Lathes, using Mandrel bores larger than 2MT had to use use larger threads and registers, but Backplates for these can always be bushed with a Myford thread and register, and then machined to suit the chuck for which they are intended.

Howard