What does it turn like between centres? thats how you normally set up a machine.

_Paul_

Kevin

You dont need a centre for the headstock, just turn a 60 degree cone on a bit of scrap bar held in the chuck.

Ian

Kevin,

I'm not familiar with the ML4, but I assume its basic structure is similar to the 7 series – i.e. it has a foot at each end of the bed, with holding down holes at front and back of each foot.

If so, then you need to go through several steps on setting up. The first essential is to know that the bed is not twisted – if it is, then the saddle will not move parallel to the spindle axis, so all turning held in the chuck will be tapered. You will be surprised how easy it is to hold the bed down in such a way that the bed is twisted. The only reliable way to correct this is to chuck a substantial bar – at least 1" diameter and 6" long – with no tailstock support, and turn small bits at remote end and headstock end at the same cross slide/topslide setting (it helps if you relieve the bar slightly between the two ends to remove the need to move the tool when switching between the two). The two lands you turned should be identical in diameter – a couple of tenths out should be acceptable.

If the remote end is larger, that means the bed is tending to move away from the tool point as you move away from the headstock; slacken off the rear bolt of the tailstock foot, and shim it slightly under the foot and re-tighten. Try again, should be better. Repeat until happy. Obviously, if that end is smaller, then shim under the front side of the foot instead.

Some people will tell you that you can do this with an engineer's level. I have an engineer's level, and I've tried it, you can't get the same accuracy (and the levels cost); the way I described is (a) more accurate and (b) free.

Then, when happy the bed is not twisted, check the tailstock is in line with the headstock spinlde axis. The proper way to do this is with a test bar and a DTI, but simply aligning centres in headstock and tailstock is fairly good.

Then you can turn between centres and know that you will get a parallel result. For holding in a chuck you need to be sure your chuck is acceptable. Old 3-jaw s/c chucks are notoriously poor in this respect. You can use a 4-jaw independent, use a collet, buy a Griptru chuck (pricey) and learn to use it, or remedy your old chuck, perhaps by re-turning the register on the backplate (or even providing adjusting screws) and possibly grinding the jaws if they are bell-mouthed.

David

Edited By David Littlewood on 05/01/2013 23:43:20

Hello Kevin,

I inherited my late father's ML4 in 1963, it was aleady about 20years old then and I ran it for a further 20 years before selling it on to buy a friend's ML7.

I suspect you have the model with the plain non-adjusting tailstock, a real pain to set up both in terms of alignment across the bed and true aim along the bed. With the single foot mounting for the whole machine, leaving the tailstock end of the bed as a cantilever, the advise above from David Littlewood about bed twist and correction doesn't apply.

A relatively quick way of setting things true to at least a reasonable approximation, and assuming you can trust your 3 jaw chuck, is to do as follows:

Slacken the tailstock foot adjusting screws and mounting bolts along with the bed clamp on the rear of the tailsock. Wind out the barrel to about 3/4 reach, clamp it with the barrel clamp and then grip the front end in the chuck. Now that at least is aligned with the headstock centre-line and with it the tailstock body.

Now you can reset the tailstock front shear dovetail and carefully tighten the bolts on the tailstock holding the dovetail piece to the tailstock, checking with your DTI that you are not moving the tailstock body as well; this may take a while.

When you are happy with that and the bolts are tight, test again as you tighten the bed clamp for the tailstock, it should not deflect more than a few thou if you have got the previous operations right.

If you have some 1MT tooling with a plain parallel section, grip that in the chuck instead of the barrel, the 1MT barrel bore is the definitive centre for the tailstock.

You might still be able to get a handbook from Tony Griffiths, visit tony@lathes.co.uk he has a wealth of handbooks for all sorts of machinery, it will be very useful for you.

I hope that helps

Brian

David,

Brian's method is correct. Harold is writing about a Myford with the need to adjust for possible  twist due to incorrect mounting,  the ML4 is, as Brian says, cantilevered and so the shimming does NOT apply.

Edited By KWIL on 06/01/2013 12:06:52

An ML4 bed will twist in just the same way as a Myford 7 series lathe if secured to an uneven surface and so the same precautions should be adhered to for both types of machine.

As has been stated numerous times before: Level the bed with a engineer's level to ensure all twist is eliminated, then take a test cut on a substantial piece of free machining metal bar, using a sharp tool.

If the bar is unacceptably out of parallel, then you need to look for the root cause, such as headstock misalignment or wear etc. If the bar is out of parallel by a thou' or two, then you could tweak the mounting bolts by shimming or other adjustment until you're happy.

The first rule though is to ensure there is no twist in the bed – particularly with a fixed tailstock machine.

Martin.

Hello Kevin,

D1992 will be the serial number. Mine was D2382, bought new by my father in 1945

From what you say, your model sounds like the non adjusting tailstock, the later Myford mod. had a tongue built in across the tailstock base [as in the ML7 which replaced it] so that it was possible to offset PARALLEL to the lathe bed when turning tapers.

Before then, with just the dovetail jib location, there was no control on the alignment at all and it was possible to set up to turn parallel and then find you were drilling at a skew from the tailstock. If you have a longish straight bar you can trust, put that in the tailstock chuck and measure displacement down its length with your DTI. If it isn't too far out I would call it a day and heave a sigh of relief!

Incidentally, the feedscrews for both X slide and top slide are 12 TPI; I know the dials are marked in 100 divs, but one full turn moves the tooling by 96thou.

I modified my headstock spindle with a close fitting collar to bring the register diameter up to 1.25 inches so that ML7 chucks and accessories would fit. As supplied, the nose was 1.125 inch register diameter with a 1.125 inch x 12 Whit thread and it became difficult to find things made to that size.

Brian

Edited By Brian Wood on 07/01/2013 10:38:23

Hello ML4 club members. My machine is D2017, which I recently bought from a club member. I have only just finished setting up my workshop and your post has prompted me to reply. I carried out the rollie's dad method of lathe alignment and after some adjustments I am happy with the accuracy. I checked against any potential twist using a fancy new electronic level device when I fitted the lathe to its bench top. I am lucky to have the adjustable type tailstock. Which I found, after checking had been offset to parallel?

My method to overcome the register diameter issue was a internal bush fitted inside a new purchase ML7 backplate. This allowed me to use the three jaw chuck that fitted the register and a four jaw chuck was fitted to the new backplate with its internal register now at 1.125". I will most likely do the same for any other backplates I get in the future.

Somebody once said there is life in the old dog yet. For our venerable lathes this seems to be the case.

It was a remark of my father's when I was 10 years old, I never questioned it at the time, or checked it later, so I could be mistaken.

In those far off days we didn't have independent means to verify actual movement compared to iindicated.

I usually measure everything anyway without depending on what the dials say

Brian

I've been turning tubes recently that needed to be 0.01mm parallel.

I used a small Myford M Type (1949) . I turned centre – centre. The headstock was a piece of steel that I put a MT1 taper on one end and a 90 degree taper on the other. At the tail stock I used a live 90 degree centre.

Due to the age and type of lathe it took a long time to setup but eventually I got it to 0.01 parallel over 300mm. Further parts have been the same tolerance too. I found 90 degree tapers to be far better for tubes as opposed to 60 degree centre that you would normally use. Also, making a cross-slide lock got me down from 0.03mm to 0.01 mm.

I had spoken to a couple of engineering companies to do the work for me, they said they couldn't do it!

Now that you have got your ml4 to turn diameters parallel try machining a bore to the same standard.

With the work piece held in the chuck or on a faceplate of course, not with a boring bar between centers.

If your lathe can do this you are as jammie as a jammie thing covered in jam!

An ml1 owner.

Edited By jason moore 1 on 19/04/2013 09:04:01