Myford ML4 Restoration: Headstock bearings and spindle removal

[Luke MitchellParticipant @lukemitchell30627]

Hi Howard,

Thanks for your comments.

Posted by Howard Lewis on 01/05/2020 16:01:44:

If you have a complete set of changewheels an additional 20T and 60T would allow you to set up for a fine feed of just over 0.004"/rev. For this, you may need to fettle the Mandrel end of the slot in the Banjo. The train is

20 : 60/20 : 65/20 ; 60 on the Leadscrew.

I have most, although not all of the changewheels. I'm missing 2x20T, 45T, 70T and 75T from the original set, although I may buy a spare 25T too as the one I have is cracked and I fear it may break at some point. I will try and braze it once the lockdown lifts and I can use a friend's set-up. I've also got a 28T, a 38T, a spare 35T and a spare 50T.

For record, I've been told the original set is: 20, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75

Posted by Howard Lewis on 01/05/2020 16:01:44:

The Cross Slide Handwheel looks to be a shop made addition, possibly to overcome the odd increments of the original 80 division dial on a 12 tpi screw, giving a 0.00104" increment.

It does, I too have wondered at the reason. I'll count the increments and see if I can come to any conclusions. I'd assumed, initially, that it may have been made to replace a missing or broken wheel as the original is no where to be found.

Kind regards,

Luke

[Brian WoodParticipant @brianwood45127]

Hello Luke,

Just briefly if I may.

The spindle nose configuration of the ML7 has the same thread as your lathe, but the plain chuck register is 1.25 inches in diameter. The modification is to make a close fitting sleeve to bond to the 1.125 inch diameter register you have and then machine the o/d using the lathe itself to finish the OD to ML7 size

You would of course need to open the register diameter on your current range of chucks.

Kind regards Brian

Edited By Brian Wood on 01/05/2020 19:21:01

[Howard LewisParticipant @howardlewis46836]

Hi Luke,

The more I read, the happier I am for you!

Shall probably get chastised by the ML7 followers for this heresy. Helping someone recommission a ML4 with 7/8 BSW nose, I cut a couple of 20T gears, and added a 60T left over from my ML7. All had to have a hole drilled part way through to accept the 3/32 driving pins. If you do this, drill the hole away from the keyway!

Not sure if 70 and 75T were part of the original changewheel set up. Thought that it stopped at 65, ,but I could be wrong. Will the Lathes UK site confirm / deny?

If you graduated the Handwheel with 83 divisions, that would be nearer to 0.001"/ division, but not absolutely accurate, (0.0010040161" per division to be pedantic )

I like Brian's suggestion of bonding a sleeve onto the Mandrel to bring the register up to inch and quarter

Might be a bit of a chicken and egg job to modify the chucks.

My suggestion would be to mount the 4 jaw and clamp the 3 Jaw to a piece of bar. Adjust the 4 Jaw until the register of the 3 is running absolutely true, before opening it up to inch and a quarter. Still using the 4 Jaw, hold a piece of bar, larger than inch and a quarter, and turn the OD to snug fit in the register of the 3 Jaw. Then bore the bar to the diameter of the original register on the mandrel (which you will have measured as accurately as possible before starting this! )

Part of the sleeve to length, and deburr.

If it is a tight fit on the Mandrel, you may be able to heat it, to produce a shrink fit.

Having fitted the sleeve to the Mandrel, mount the 3 Jaw (hopefully a really snug fit ) and skim a bar to produce a true concentric diameter.

Clamp the 4 Jaw to the bar, register outwards, and adjust its jaws until the register runs true.

Bore out to the OD of the sleeve, or a thou oversize.

Hopefully, you should then have a Mandrel and two chucks that are compatible with other Myford 7 Series fitting items.

If you have a Faceplate, or anything else fitting the original register, you will need to treat that in a similar way to the chucks..

HTH

Howard

..

[Luke MitchellParticipant @lukemitchell30627]

Hi Howard,

it does indeed seem that 70 and 75T are non-standard and were available to "extend the threading range" (see lathes.co.uk).

There was recently a set of ML1/2/3/4 changegears up for sale on eBay that I contemplated but the lot sold very, very quickly. I think I'll buy the gears missing from my set from the available ML7 stock and drill the 3/32 holes for the pin (opposite the keyway). It seems easier than waiting for [rare] earlier gears to crop up.

There is also a fixed steady available on eBay at the moment but only for the earlier 3-1/8" center height. I'd love the opportunity to acquire an original fixed steady for this ML4 but I may have to do with machining down one for the ML7. I believe the ML7 travelling steady will fit with minimal modification, however.

Cheers

Edited By Luke Mitchell on 01/05/2020 23:13:00

[Brian WoodParticipant @brianwood45127]

Hello Howard and Luke,

I was quite taken up with Howard's suggestion for re-machining the backplate register on Luke's chucks. I do however see a snag which would ruin the whole operation.

It depends crucially on the quality of grip of, say, the three jaw chuck on the machined spigot held in the four jaw chuck. Luke has already said his Crown 3J chuck has a lot of wear and uncertainty of grip in the jaws which means it will grip the spigot well enough but would that be without a wobble at the register position?

I think instead there is little alternative to removing the backplate from the chuck to be modified so that the register position can be set correctly in both planes.

When I carried out the modification on Dad's lathe I had the advantage of owning a second 4 jaw chuck, big enough to grip backplates on their own so that location in the two directions could be assured.

Good news for Luke

You will find that the location tongue of a fixed steady for the ML7 will also fit the central channel between the ways on your ML4. The gap width is 35 mm. Whether the position across the bed of both lathe designs is sufficiently close as to be insignificant I don't know.

I made a large 4 arm steady for the ML4 to machine the bearing pockets in the quill tube on my Dore Westbury milling machine and have used that on my ML7R many times without being aware of cross bed misalignment

Kind regards Brian

[Brian WoodParticipant @brianwood45127]

Hello again Luke,

I have just been reading back over the recent correspondence and noted your report on the cracked 25 tooth gear.

I feel sure I am correct; Myford made the smaller gear sizes in steel, which would include 25T. The other sizes upwards were made in cast iron

My question is how on earth did a 25T gear in ductile material get cracked? I can only think that there was at some stage in it's life one almighty lock up, maybe from running the tool into the chuck or something on those lines for there to have been sufficient strain induced in the gear to crack it. If that happened on this lathe I would look carefully at the other elements downstream of the change gears for evidence of damage.

It may of course have been bought in along with other things, in which case you will see nothing untoward.

I recently rebuilt the screwcutting gearbox on a 1902 US made Hendey lathe fitted with an original Norton box. That had been very badly beaten up in a hard life and I had to make a completely new set of gears for it but the point of the story in that while the cast iron [Yes–cast iron!] gears were mostly devoid of teeth, the smaller steel ones still had teeth, all bent and distorted. , some worn down to stumps, but NONE were cracked.

A cast gear would have fractured—I remain puzzled

Clamp it together when you braze it to prevent it opening like a flower and anneal it well afterwards to relieve strain

Kind regards Brian

[Howard LewisParticipant @howardlewis46836]

Quite right Brian,

I had forgotten that the 3 jaw was questionable about grip.

Could this be overcome by using bit to produce a"collet" to hold the bit of bar? A relatively thin wall would allow it to collapse and grip the bar, hopefully retaining the alignment and grip of the dicky chuck.

(A candidate for a bit of in situ jaw grinding with a Dremel? )

As you say, tit may be possible to use the 4 jaw to turn the backplate register of the 3 jaw. If the backplate / chuck fit is tight, concentricity errors should be minimal.

Howard

[Brian WoodParticipant @brianwood45127]

Hello Howard,

I am inclined to think that introducing another variable, in this case a thin walled sleeve, will only add to the problems of concentricity. I really can't see much alternative to removing the variables and machining the new register while it is held soundly in the 4 jaw chuck.

Kind regards Brian

[Howard LewisParticipant @howardlewis46836]

Hi Brian!

Correct again!

The fewer variables, the greater the rigidity and accuracy. The "collet" would be a bit of a last resort., in my mind.

The risk here, is that dodgy 3 jaw chuck. if a means of improving its grip and accuracy can be found, things will improve. I wonder if the problem stems from wear between the scroll and the jaws, or jaws and chuck body.

Even grinding the jaws, in situ, will probably only mean accuracy at that one diameter with discrepancies elsewhere.

Anything that can be done to reduce the play has to make things better.

Maybe, the ultimate solution is to scrap it and buy a new one, with a "Myford" register, funds permitting?

Howard

[Andrew ByronParticipant @andrewbyron13518]

I hope Luke doesn't mind me butting into his thread but I have also recently acquired what i believe to be an old ML4 lathe with a view to fettling it back to usable condition and hopefully learning how to use it. Reading this thread and a couple of other related threads on this forum having found them by googling info on the ML4, i have found the information most useful.

My lathe, to my inexpert eye at least, doesn't look to have excessive wear in it,i think it was used for many years by a model engineer and hobbyist, in more recent times it's been owned by a guy who wasn't really an engineer and was just playing about with it occasionally, so it's neglected a bit but i think basically ok. In all i was quite please with the purchase which was a blind buy on ebay, until that was i took the guard off the bull gear, you can probably guess the next bit.

I've realised that the drawback with these machines is the lack of spare parts, i did manage to purchase an incomplete similar lathe with just the major components on it, head stock, cross slide and tailstock, with a good bull gear on it, for £60 on ebay just before the problems with the covid virus became apparent, however it's quite a way from where i live and i've got no way of getting it back here whist the lockdown is in place.

I'm planning to convert the spindle to take an ML7 backplate as suggested here by Brian Wood, so the information on this thread has been extremely helpful to me

many thanks

andrew

[Luke MitchellParticipant @lukemitchell30627]

Hi both,

Many thanks for the musings about my 3J chuck and the register adaption. I will need to think about it and weigh up the pros and cons of the process – it certainly seems worthwhile, on the face of it, but perhaps not urgent unless I fail to true up my chuck (in which case I suspect I will have to buy a newer one).

Since removing the spindle I have cleaned up the spindle gear and I’ve left the thrust bearing in some acetone to degrease it. It looks as though there are a few flats on the ball bearings and so I will be replacing it. I’ll take some measurements later today and find the appropriate part. I’ve also deburred the spindle using a fine file and a stone so hopefully I will not damage the bearings when I refit them – it was a nerve wracking experience but I think a successful one. We shall see.

I will take a look at the 25T gear too and take a photograph. I’ve not noticed anything that would indicate a crash – the change gears all seem to work and fit well and the lead screw is in good condition (although there is a bit of a flex in it, I’d chalked that up to the thickness/length). Perhaps the crack is nothing more than a scratch that is full of old swarfy oil.

More updates soon.

Kind regards, Luke

[Luke MitchellParticipant @lukemitchell30627]

Hello again.

I dug the thrust bearing out of the acetone – it's partially cleaned up the muck inside it but it will need a bit longer, and possibly some agitation. Here are a couple of photographs in which you can just see the flat spots. The flats on the ball bearing at 8 o'clock and 4 o'clock in the second photo are particularly obvious.

As for the 25T gear, it was indeed cracked. It's strange as the teeth of the gear look in very good condition. It looks as though my changegear set has been taken from an ML7 as each gear has a keyway cut into it. See the photograph below.

Kind regards,

Luke

[Luke MitchellParticipant @lukemitchell30627]

Here are another photo of the cracked gear (I posted my previous message in a hurry as I was late for an online chat with a friend). I couldn't discern any noticeable difference in material between the 25T gear and the larger sizes – as you can see in the second photo they all look very similar (and are in remarkably good condition, to my eye).

[Brian WoodParticipant @brianwood45127]

Hello Luke,

The thrust bearing

I suspect the bearing has been skidding. You did say some while back that the screwed collar was slack so there would have been no pre-load on it. It was also lubricated with grease which would tend to hold the balls in position as the grease dried out and it got stiff, adding further to the problem. Buy a new one, it should be realistically priced

The cracked gear

I was right it seems, this was NOT original supply, Keyways were introduced in ML7 change wheels, not for the ML4. Starting from the stress raiser in the keyway corner it must still have been given a substantial shock to have cracked. However, it will salvage well. I suggest you drill out down the centre of the crack at the tip to remove the stress raiser there in particular so that you can get braze metal all the way through onto clean metal and anneal it by very slow cooling after the brazing with it buried in vermiculite

Kind regards Brian

[Luke MitchellParticipant @lukemitchell30627]

Hi Andrew. Forgive me for ignoring you, I must have missed your comment earlier.

I agree that one of the more difficult aspects of owning an early Myford is the lack of parts that are available. Looking on eBay there is a wealth of spares and accessories for ML7s, ML10s and the Super 7 lathes. The lack of detailed information is also a problem as, until finding this forum, I’ve had to piece everything together myself. I did buy the data pack from lathes.co.uk but there wasn’t a great deal more than can be read for free – just some nice figures and old sales photographs.

Brian mentioned earlier in this thread that he had a spare 60T bull gear. You might consider asking him to purchase it to replace your [rather unhappy-looking] one. I can’t tell in the photo but are your back gears in decent condition? There is a backgear cluster for sale on eBay with only a single missing tooth that may also be of interest to you.

Kind regards

[Luke MitchellParticipant @lukemitchell30627]

Morning all,

I've just taken some more measurements for the thrust bearing assembly and I'm looking for a replacement to purchase.

The measurements I took were as follows:

OD: 41.3mm (1.6" )

ID: 25.73mm (~1" )

Depth: 11mm (7/16" )

Taking a look at some of the bearing providers it seems that this is close to a standard size that's still available: 42 x 25 x 11mm.

My next question is that both ball bearings and roller bearings are sold. It is my understanding that roller bearings are superior and I was wondering if it would be worth considering "upgrading" the existing bearings for a roller-type bearing?

See ball-type and roller-type bearings.

Kind regards,

Luke

Edited By Luke Mitchell on 04/05/2020 09:31:17

[Brian WoodParticipant @brianwood45127]

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

[Luke MitchellParticipant @lukemitchell30627]

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

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.

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

[Brian WoodParticipant @brianwood45127]

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

[david bennett 8Participant @davidbennett8]

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

[Brian WoodParticipant @brianwood45127]

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

[Brian WoodParticipant @brianwood45127]

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

[Jon CameronParticipant @joncameron26580]

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

[Luke MitchellParticipant @lukemitchell30627]

Posted by Jon Cameron on 04/05/2020 16:46:48:

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

[Brian WoodParticipant @brianwood45127]

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

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