ML7 alignment problem

Interesting. The leadscrew dips when you engage the halfnuts? I have the same problem but the other way round, my leadscrew lifts slightly when engaging the halfnuts. Not as much as 80 thou though, thats rather a lot!

The original bed thickness is nominally 0.500" so they have only taken around 0.005" off at the regrind so surely it can't be that. Mine had around 0.006" taken off the bed, but when I reground the saddle I had to take 0.008" off to get rid of all the wear, so that would have altered things a little bit. I ground it the same amount on the bearing surfaces and the clamp faces.

I too would be interested to see if anyone has had/fixed this problem.

Peter

Variation on [1] Plug the holes with top hatted plugs to fit the hole and counterbore, press in and loctite, then redrill.

-- Regards,

John Stevenson Nottingham, England.

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That might be the way to do it. If I turn up some 1/4"BSF studs with points on the ends, I can screw them into the holes in the bed and tap the blued-up brackets against them to get the new centres to drill from.

Do you think that 603 Loctite would hold half a plug in or should I drill the holes out large enough that the new holes are entirely in the plugs?

I'm sure it'd be easier to just slop a tin of grey paint over the lathe, but I'll be damned if I'll sell something that I'd not be happy to keep.

Mark Rand RTFM

Variation on 3 Plug the holes in the half nuts, redrill & tap?

I strongly suspect that that you are only working in 2D whereas the complaint appears to be in 3 D!

The wear on a ML7 bed appears AFTER the lathe fails to surface properly. This relates to the wear in the central tongue or guide system. I know that it sounds cockeyed- but better people than me and thee have written on it. The Question is "what happened- afore thee and me?" Did the original owner adopt 'scrape the tongue' method or adopt going off the (?) unused rear shear method as advocated by Martin Cleeve? Or, did something else happen- before the 6thou came off the bed? Again, the front shear will probably continue in use but 6" from the chuck end it will be hollow- and have the gibs been re-scraped- or the whole lot might be flopping about in the breeze like a loose cannon.

Years ago, I wrote how I did up friend's ML7 in MEW Postbag. Lord knows where it is- I'm technically in need of more than a regrind and a few perforations bunged up. I think that my my order was a bit like this

1. I scraped a ms bar to level the front
2. I checked the inner ways for the tailstock etc
3. I used a hand surface grinder to do all the worn gibs
4. I mounted the saddle upside down on parallels and squared the whole bottom of the saddle

Once the lathe is a Static entity- you can move on!

If there is another easier solution, please tell us

Cheers

Norm

I take it that the Martin Cleeves idea of using the rear shear involve

milling enough off the rear of the saddle to accomodate a gib strip Would like to know as I have a spare saddle I could play with. Thank Davi

-- stereotyp

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You can do that, or you can mill an appropriate amount off the leadscrew mounting brackets. If gib strip is a length of 1/2"x1/32"ground flat stock, you may find that scraping for alignment is all that is needed. Once you've done the alignment and fitting, hold the gib in with some Loctite.

Mark Rand RTFM

Don't know if it applies to the ML7,but on my Super7 the bushing that the operating arm goes through is eccentric to enable the height of the closed half nuts to be adjusted.

Allan

It isn't on the ML7 but, come to think of it, that would be the obvious fix!

Mark Rand RTFM