This may help;

**LINK**

Brian

What do you mean by "tapered"? The standard Myford thread is 1 1/8" 12 tpi. There should be a 1 1/8" plain "shoulder" near the main body of the spindle, normally called the "register" which makes the backplate run true (if the latter is accurately machined). If your nose actually tapers in diameter you have a problem! It would be seriously worn.

The tapers don't sound anything like Myford chucks. Something weird is going on.

Before you can get any kind of meaningful advice, you really need to identify from lathes.co.uk what model of Myford you have. And posting some pics of the tapered spindle and threads would be most helpful.

Here's a picture of a myford thread, it is not tapered.

**LINK**

Yes I'll go with the ML 4 as a best guess so far . The identifying detail is in the headstock and leadscrew attachments and the tailstock. The foundry patern numbers are as Hopper says a constant blind alley when identifying the 1234 series of lathes. Don't expect it to take off huge chunks with an insert tool and you'll find it does a tidy job when set up. The thing with these very light lathes is that everything takes twice as long to do , I recon that means they're twice the fun.

If you mean a standard ML7 backplate, no it is not quite the same. The ML7 register collar is slightly larger diameter than the thread, maybe about 1-1/4" or so. Tony at lathes.co.uk does sell a range of backplates, he may have one suitable for the ML4 spindle.

The thread in your pic looks well used but still useable. The chuck is located by the register collar and the face on the shoulder behind it, so a sloppy thread is not the end of the world.

It looks like a ML3 or 4.

A Ml1 or 2 would have a centre height of m3.125" where the 3 and 4 are 3.5"

The ML3 is 15" centre distance, where the 4 is 24" (Confirm with Lathes UK website )

Yours appears to have the optional Tumbler Reverse and the side hinged cover for the Changewheels.

The Leadscrew is 8 tpi, but the Leadscrews for the Cross and Topslide are 12 tpi. The dials for these have 80 divisions, which means that each division is not 0.001" but 0.00104"

Chagewheels are driven by driving collars (secured to the Mandrel and Leadscrew by 1/4 BSF grub or capscrews.

(Virtrually all threads, except possibly the gib adjusters, will be BSW or BSF )

To transfer the drive between the collars and gears, or to compound gears, there is a 3/32" pin in a blind hole in each part.

If you are short of Changewjheels, those from the 7 Series will fit. Dimensionally they are the same, but have a keyway instead of the 3/32 hole.

So you will need to drill through one original gear to use as a template. Fit both gears onto one of the changewheel studs, and drill though into the 7 Series gear, keeping away from the keyway..

With additional gears, you can set up a fine feed, 20:60/20:65/20:60. This will give a fine feed for turning of 0.0000427" / rev. You may need to fettle the inside of the Mandrel end of the Banjo to enable the first stud to move far enough to set the correct mesh for the gears.

My advice is to set the mesh, starting from the Leadscxrew, and working your way to the Mandrel. Just run a piece of paper about 0.003" thick between the gears.

HTH

Howard