Myford ML4 Restoration: Headstock bearings and spindle removal

Hello again Luke,

Andrew has replied to a PM I sent him, we will be sorting out an exchange of my spare bull wheel in due course. Just to make a pedantic correction, ML4 bullwheels have 65 teeth to be awkward for dividing purposes, the ML7 bullwheel has a more useful 60T gear and in a more robust 16 DP form. If you are still interested in replacing yours, I made a small batch of them some while ago and have another one available

I've had another look at your cracked gear, this time in the second picture. I can't be sure, but isn't there a darker line in the root of the gear that might indicate that the crack has propagated right through? There is also, to my mind, something very odd about the path taken by the crack, it is shown well in the first picture. It doesn't actually start from the corner of the keyway as I would have expected, it is very straight and at right angles to the keyway.

In my experience, such a crack would not be ruler straight and would run at some angle nearer 30 degrees or so away from the sharp corner.

Just to satisfy my curiosity would you mind scrubbing it with acetone and get a lens on it to look closely at it? There is another line at about 9 o'clock which is obviously scored, the similarity is marked.

Kind regards Brian

Edited By Brian Wood on 04/05/2020 10:05:13

Posted by Brian Wood on 04/05/2020 10:01:17:

Hi Brian,

I'm sorry that the photos are not very clear. You're correct - the crack does propagate all the way through and, indeed, continues down the other side of the gear. It's as if the gear has been loaded sideways and split.

I will try and clean it up properly and take some well-lit photographs with my camera (I used a phone for the others) at some point.

Apologies for the misquoted number of teeth on the bull wheel. I did wonder if it was wise to do so without checking! I'll send you a PM about your spares as it might be useful to have a back-up, just in case.

Kind regards,

Luke

Hello again Luke,

There is no need to apologise, you have the component and can study it from all angles, it is not a luxury available from a photo.

It might well be that there was a sulphide inclusion in the bar from which this gear was made that would have led to a one sided weakness in the finished gear. They tend to align themselves in a linear fashion, especially so if the bar has been drawn down to size, and of course will form a plane of weakness leading to fracture later.

I will amend my salvage instruction accordingly if I may and suggest you saw down the path of the crack with a Junior hacksaw blade to leave clean metal on each side and braze that up. You do need to give the braze a chance to wet the joint, something it will fail to do at the moment.

I had a half shaft failure on our old Landrover arising from just such a source. It propagated as a fatigue crack in a spiral path over a 6 inch length until the final fracture point which came as I was reversing up the ramp into the garage. That little piece still holding the shaft together was about 1/8 inch in diameter!

Kind regards Brian

PS My email address if you care to contact me that way is wood_y(at)btinternet(dot)com Be sure to include the underscore between the d and y

Edited By Brian Wood on 04/05/2020 10:37:27

Re the chuck register question - I suggest you read "fitting a chuck" on Tony's site (lathes.co.uk) especially the last paragraph. I have a ML4 like yours. I am happily using ML7 chucks with no problems. A close fitting register is not necessary.

Dave

Edited By david bennett 8 on 04/05/2020 13:49:02

Hello David,

That is a rather controversial viewpoint, that many will take issue with, including myself. Irrespective of what you have read, I think you might ask yourself why the lathe makers, without exception, bothered with location registers in the first place..

Just as an experiment. If you have a faceplate, try fitting it the wrong way round and see if it still runs true.

Regards Brian

David,

I have now read the relevant paragraph and the critical phrase is that the chuck backplate must still abut the vertical register location.for it to run true.

Despite what Tony says and I hold him in very high regard, I still believe the diameter register is important as it acts as a guide for the chuck to be aligned as it is screwed on and not just depend on the final butted joint when it reaches the rear vertical face

Regards Brian

Interesting thread.

I also have an ML4 currently stripped down for painting and to remedy a few issues that where bothering me.

Brian has been a great help to me when I first got the lathe, to get it up and running.

On the note of the fixed steady, the ML7 one wont fit the ML4 without modification to the lugs at the bottom, I have an Alomco milling attachment and my friend milled me an adaptor plate to allow fitment to the ML4, as unfortunately the ML4 gap between the ways is a little narrower. I have one of the original fixed and travelling steadies, these are currently stripped, for again refurb, I have offered to make drawings for another person on a facebook group and quite happy to share these here. Although it will be built up using steel plate, welded then machined. Unless someone fancies making pattern and casting them, It wont be as graceful as the cast original but will be up to the job in hand, if not more ridged been of solid steel construction. The original had a flat base with a 3/8" BSW threaded plate, which is rounded 1/2" radius (I think) on opposing corners to help it locate under the bed and lock the steady to the bed. Four "fingers" are then mounted on swivelling retainers that are fully adjustable around the bore. The top half been hindged so that work can easily be lifted clear of the steady, without disturbing the steadies position.

If you are interested I can make the drawings available once they are done.

Jon

Hi Jon,

If you could make the drawings available that would please me tremendously. As I've mentioned, I'd like to restore the machine as well as possible and, whilst it's unlikely to ever be of watchmakers precision, if I can collect or fabricate some of the more useful accessories (such as the steadies) I think (and hope) it will stand a good chance of being a usable day-to-day lathe.

I'm glad you've found the thread of interest. If you wouldn't mind, could you briefly explain any caveats you've found/overcome on your machine?

Kind regards

Hello Jon,

I wondered if you have been following this thread.

What you say about the gap in the bed ways comparing ML4 and ML7 is very interesting. I can only pass on the experience I had with Dad's old 1945 ML4 and now my current ML7R, The width of the guide tongue in both is exactly the same at 35.00 mm but I will admit that on the 4 arm version I made to fit the ML4 it needed a couple of flat strips either side of the tongue to bring the centre point up to something nearer mid position. Those strips are maybe 1mm thick, they are bonded on over the whole width and without opening the workshop again this evening, I am only quoting from memory.

I seem to remember recommending that you incorporate the modification to bring the register diameter up the ML7 specification while you were overhauling the lathe, may I ask if you went ahead with it?

Kind regards Brian

For what my advice is worth, I am fully in agreement with Brian about holding a close clearance on chuck registers.

In the case of a 3 Jaw chuck, it will have some eccentricity anyway. There seems absolutely no sense in having a slack fit between chuck and mandrel, to make matters worse.. If you have that, you will have no idea what run out there is each time that you fit, or maybe, even, use the chuck. That will make holding diamters concentric more difficult. And if you are merely trying to take a skim to clean up, will require a deeper cut, which could be more metal than you want to remove.

A 4 jaw chuck will allow you to compensate for any eccentricity of the chuck, but why make extra work, for no good reason?

Howard

Edited By Howard Lewis on 04/05/2020 18:27:10

The subject of nose registry has been done to death on many other sites. Don't forget the nose thread is an inclined plane, and together with an accurate abutment face acts similarly to a nose taper. I suggest we ask the original poster to try an ml7 3 jaw chuck before modifying the lathe nose and let us know if it repeats well.

Dave

Hi all,

I've just taken some measurements and the gap between my ways is 20.2mm. This is considerably less than the 35mm that you mention, Brian.

Jon, does that couple with measurements for your machine?

If I purchase or come across a chuck with an ML7 backplate, which is quite likely if I can't improve upon my existing selection, I will try it as-is and take some measurements. For science.

I am inclined, however, to make the modification. It seems the more trustworthy option and, to boot, the change is not a permanent one and so the ML4 can be restored to it's original state if necessary (although this may well be difficult if the fit is good enough!).

Cheers

Hello,

2nd attempt at a.(shortened) reply, Luke, I'll get measuring the steady and sharpen my pencil. It should be possible to build it up and machine it back from bar stock.

I actually came across this thread by accident, though glad I did as hopefully I can repay some of the help I recieved when I started with mine.

I never did make an adaptor.for the spindle nose as been a poorper machinist the cost of buying new 3 and 4jaw chucks, and faceplate ect. Wasn't viable at the time, however as tooling increases the more I have bought that needs the 1.1/8" thread. The lathe came with plenty of tooling already threaded 7/8" 9TPI so I have kept it as it was.

There is a lot of issues that has prompted my lathe been pulled apart, the main one was the motor running hot. There was a knocking from the layshaft, (not a myford one), on stripping down the motor pulley has never been keyed and had come loose on the shaft, also the bearings for the layshaft (they look like brass) have worn oval so combined it was making a heck of a racket. Theres a few other issues that I'll be sorting out. Plus now i have garage instead of the 6x4' shed. So there was another reason to strip it down, I have room to do bigger projects.

If I can be of any assistance just ask.

Luke, the first reply I posted detailed the bed. Mine measured 25mm between the ways and is raw cast. 75mm over the bed ways.

From what I have seen of the M types, the official steady would probably clamp across the dovetail bed.

For one ML4 owner, I made a Saddle Stop which did this.

So, possibly, it may be possible to make a fixture to clamp to the dovetail, and have a steady fixed to its top?

Just a thought

Howard

Howard the original fixed steady for the ML1,2,3&4, has a flat soleplate, and a 1/8" plate, to a 3/8" BSF bolt which pulled the steady into the ways. It should be possible to build one up (although not as ornate) from 20x100mm plate, around 150mm off, some 5 or 6mm x 40mm plate, around and some 1/2" steel round. Either bolted or preferably welded before been machined down. The ML10 and M-type lathe both utilised the dovetail ways to locate onto the bed.

Luke is the second person now owning an ML4 that wishes to have a fixed steady, so would be practical for me to measure and do a set of drawings so they could be used to fabricated up.

Luke thanks in advance for your future efforts for science!.The ideal time to try this is when you

are trueing your new backplate to your lathe. When it is true,de-mount the backplate, then try to re-mount it off centre.Let us know if you can.

Dave.

Gentlemen,

I live and learn along with you. Dad's ML4 had a machined gap running down the centre of the bedways, I made my 4 arm steady using that as the locator to keep it at right angles to the lathe centreline.

With my present lathe, the ML7R and it's predecessor the ML7, this big steady fitted that gap of 35 mm precisely so in my ignorance I assumed the earlier ML4s were also machined and to that dimension.

Clearly I have something to learn from this aspect although I would just add that the accessories section in Dad's handbook shows a three arm steady [and rather crude it was too with round steel fingers] located from the gap between the bedways, not across them.

Kind regards to all Brian

Hi Brian, I must admit that having the centre section machined would be advantageous for setting up tooling such as a fixed steady, it would have also eliminated the cost of having the adaptor plate made for the alomco milling attachment. hey ho.

Perhaps the centre section was machined at a later date, or requested when your father bought the lathe from myford.

The steady you describe is what I have with the three fingers around the bore, with the top piece pivoted so it can be opened to retrieve the work piece. I have some of the steel mentioned earlier so if I can get the drawing finished and ledgible, (i'm no draftsman, but try my best), I will make a start on welding the bits together to build up the base, and pivot. Having a think on machining it last night. it will all be able to be machined on the faceplate, utilising an angle plate or packed up on the cross slide for drilling the hole in the base, (a little less precarious), with less overhang from the faceplate.

Jon

Hello Jon,

Considering I would have been maybe 5 or 6 years old when Dad ordered his lathe, I can't be sure if he asked for the gap in the bedways to be machined. I rather doubt it though, I am pretty sure that is how it was supplied at the time. Certainly it was never machined later.

He also had to convince the pen pushers in the Ministry of Supply to issue him with a wartime Machine Tool Licence to be able to buy it in the first place. The excuse was that he needed it to be able to re-machine cast tungsten carbide glazing cylinders used in his leather factory to put a shine on the finished product, while at the same time bringing out the final colour from the previous matt finish. And as we all know of course, grinding is the only way of coping with that requirement, not with a lightweight lathe. ..

With the pretty well complete absence of any kind of understanding by the civil servants of mechanical matters [much like today really, little changes] the license was granted, the machine and accessories were ordered BUT it was delivered to our home, a flat adjacent---it never went into the factory!! He was always rather proud of the con he had pulled.

Kind regards Brian

Edited By Brian Wood on 05/05/2020 11:34:24