Hello all.

Firstly, I am a first time poster here. I found the site after looking for other ML4 restorations (of which there seems to be precious little, at least not publicised on the internet).

I have recently inherited the lathe from my grandfather. It was his brothers and he doesn't have a great deal of information about it – save that it was often used and clearly loved. It has sat now for a long time, a decade or more, and is in need of some love.

I stripped down, cleaned and lubricated as much of the lathe as possible and I've managed to turn a few simple projects using it: a sink plug, made using brass; an arbor for an angle grinder; boring out a pulley wheel.

On aluminium and brass I can get a fairly good finish. When parting, or cutting steels, however there is a lot of vibration and chatter and a whirring sound from the headstock. There is also a little vertical play in the spindle (about 0.2mm, measured using my cheap DTI) and a little run-out (0.03mm).

I was told that the headstock bearings would need replacing and my experience turning seems to confirm this.

This evening I carefully adjusted the clamp bolts in the headstock, taking care not to over-tighten them as I've read this can split the casting. I then nipped up the grub screws until the spindle seized, then backed off 1/4 turn. This operation eliminated much of the vertical play (it was reduced to ~0.05mm). However, when I powered up the lathe and began turning it produced an awful chatter even during shallow cuts. Slackening the clamp bolts helped but brought back the play.

I believe the vertical play is making parting, in particular, very difficult. More than once the work has jumped onto the parting tool.

Some details about the lathe:

• 1.1/8" x 12 TPI thread on the spindle nose
• 3.1/2" height between center and ways
• MT2 in the spindle
• MT1 in the tailstock
• Tumbler reverse
• "Newer" tailstock casting with large dovetail gib
• Toolpost bolt has been re-tapped to M10 at some point

The spindle thread leads me to suspect it is a later ML4 as this is the same (I believe) as the ML7. The serial number has been painted over however and so I cannot use this to age the machine.

Some (slightly random) photos:

(Post continued…)

At some point I would like to completely strip, sandblast and repaint the castings. I may also have the ways reground as they are a bit worse for wear. For now, however, I would like to get the machine up and running and usable.

Also on my to-do list is to replace the motor and the belts. The original motor sparks when powered on and is in need of a good clean and possibly a re-wind. I have a new 3ph motor with a VFD waiting to be installed but the cabling appears to be lost in transit (the post is a little crazy at the minute). When the new set-up has been installed I'll order two new belts and tension them correctly.

I am now intending to remove the spindle to examine it and, if necessary replace the bearings. I'm a little scared about this operation as, at the moment, I can't see any obvious way to remove the spindle.

The attached gear on the left-hand side seems to be stuck – it looks to me as though there should be a locating pin or bolt but, if so, this is missing and there is just an offset hole (see last photo).

Has anyone removed an ML4 spindle and, if so, could you please describe how to do so?

I hope this was of interest to some of you and, if anyone who is a former/current owner of one of these lathes has any advice, I'd gratefully receive it.

Kind regards and stay well

Luke

Hi Brian, and many thanks for taking the time to give me such a detailed reply.

I'm a little concerned that the spindle gear has seized onto the spindle. You mention that it is a very tight fit – it certainly seems so! It also appears that the 2BA screw has been lost on my machine and that the gear has slipped a little over time. I've included a photograph below.

I will have a think about the best way to remove the gear. I suspect I will have to lever it out against the collar, as you mention that you once did. If possible, it would be nice to fasten something securely around the teeth (somewhat like a collet) and to pull it off that way as I suspect it will reduce the chances of causing any damage. If anyone has any bright ideas please let me know!

Another question I have is concerning tee-bolts. I have measured the slots as best I can and they appear to be 3/8" at the narrowest width, 3/8" deep and a shade over 1/2" wide at the bottom (I measure 13.5mm which is actually 17/32" ). Does this sound usual?

Also, short of making my own (I have no access to a mill, unfortunately), does anyone know a good source for some tee-bolts so that I can use an angle plate and make up a rear tool post.

Kind regards.

Edited By Luke Mitchell on 29/04/2020 10:49:45

Edited By Luke Mitchell on 29/04/2020 10:49:57

Hi Brian, and thanks for your continued advice.

I'd not realised that the screwed collar was threaded – I've loosened the grub screw and found that it will rotate a small amount but, not having been able to fully extract the spindle, I didn't realise it was fixed using thread – I'd assumed, naievely, that the collar was unable to rotate as it was a little deformed.

I will have a go at the removal over the next week or so and report back with some photographs.

Many thanks

Here are some photographs of the casting, spindle removed. The left-hand bearing can be seen in place. It had clearly spun at some point and the oil hole was some 90 degrees off. The right-hand bearing came out with the spindle and I took the opportunity to take a look at the casting (which has quite a few voids).

I hope those images are interesting to someone. Whilst I'm posting them it occurs to me that there are rather a lot of them!

I could feel a little play in the bearing which remained on the spindle as I extracted it and I tried to photograph this to illustrate it. It appears that the gap is something around 0.5mm. I should have used a feeler gauge but I didn't have one to hand – I can try that later. The gap can be seen in the following photograph (the bearing is pushed flush with the spindle on the underside).

I removed the bearings from the spindle, cleaned off the old, grimy oil and put everything in bags for tomorrow. I could see a few high spots, blunt burrs that I can carefully stone down, but mostly the damage was indentation.

Here is the second bearing. This one looks to be in a slightly worse state that the one that remained in the casting. I believe that the damage to the spindle held it in place as it was removed. The same damage rubbed on the bearing as I removed it from the spindle – you can see a spiral where I twisted the bearing free. This is even with a liberal heat using the torch beforehand.

Please let me know what you think/suggest. Is the damage excessive for a usable machine or is this "normal" wear and tear for a machine of this age?

Kind regards

Edited By Luke Mitchell on 30/04/2020 23:45:00

Edited By Luke Mitchell on 30/04/2020 23:45:17

Edited By Luke Mitchell on 30/04/2020 23:46:24

I’m afraid I can’t see any way to edit the above posts but it seems that hosting via Google hasn’t worked as well as I hoped.

Here is a link to the photos uploaded somewhere else.

Edited By Luke Mitchell on 01/05/2020 07:53:23

Hi Brian. Once again, thank you for your valuable input.

It's good to read that the wear seems to be normal, or at least expected. It's also nice to see you write that the lathe seems to be in good condition; certainly it will have been well maintained by my relations during use – I know it has sat idle for at least one long period, however.

I'd not considered the socioeconomic background to the manufacture of this lathe before but it makes complete sense that resources (and finances) were scarce.

As you guessed, I have no experience scraping bearings or housings and I'm reluctant to try on such a project. Perhaps on another, more easily replaced part, I will try it.

My intention is now to clean up the parts as much as possible (I'll use your petrol trick, thanks) and to reinstall them before adjusting as carefully as possible. I'll then measure the run out, try the lathe and see if I've made any improvements.

Concerning the thrust bearing, I guess this should be reinstalled with a grease rather than relying on oil from the oiler cups. Will a general-purpose molybdenum grease be suitable?

The second half of your message seems to have been lost – the first half has been posted twice, perhaps by mistake?

Kind regards

Hi both,

I've included an image showing the ways (I posted it originally but I no longer trust Google and so I've re-uploaded it, elsewhere). They are indeed a little worn near the chuck, and a little discoloured at the far end beyond where the tailstock usually sits, but they still appear to be flat and mostly true. There is a slightly tight spot in the middle of the bed that it can be a little difficult to get the tailstock past but it's nothing to complain about.

If I can get the rest of the lathe running reasonably true then I will investigate regrinding the ways and re-seating the saddle. If possible (and particularly due to the history of the lathe, as you say Brian), I would like to restore it working order in the best way possible. I'd need to contact a local machine shop and get some quotations for this work but I fear it will be rather expensive.

The tapers seem to be in good condition. The headstock is bored to MT2 whilst the tailstock accepts MT1 tooling. I haven't noticed any wear to either and the tooling I've used fits snugly – indeed it becomes quite difficult to eject from the tailstock and needs to be knocked out with a wooden dowel and a mallet. Many other lathes, I notice, are abke to auto-eject tooling. Perhaps that was a later development.

I've used the tailstock taper quite a bit to support work (a necessity given the play in the headstock and, I suspect, a slightly worn 3-jaw). I've also used it for drilling and reaming and it performs well at both tasks.

It did take me some time to get the tailstock properly aligned to the headstock and the first few holes I drilled we a little off-center. Once I'd managed to slackened off the bolt holding the castings together I could use the set-over adjustment, a knurled wheel on the rear, to center the points of a taper held in both tailstock and headstock. The tailstock is still a touch lower than the headstock and I will have to use some shim stock to raise the casting. I'd also like to purchase a test bar to make sure my adjustments are accurate. (But all of this after the headstock bearings are in order).

Workholding-wise: I have a 3-jaw self-centering chuck ("British Crown", fitted in the photographs), a 4-jaw independent chuck ("British Crown&quot and a spare 3-jaw that I need to restore. As I mentioned, the 3-jaw doesn't hold stock very true and I suspect the jaws are worn unevenly. Any information about this would be appreciated but, if I can get everything else tightened up, I will look into grinding them concentric in-situ using a toolpost grinder (which I'll have to buy/make/cobble).

I have the original toolpost, which is a simple vee-shaped piece of steel with some patterning for grip, but I believe it's missing a spring and a secondary bolt. It's on my list to make up these missing pieces so the original toolpost can be used again.

I've installed an Indian-made Dickson-style QCTP as I quite quickly got fed up of shimming up tools to the center height. It's not the best quality but it works well, especially after I made up a brass bushing to grip the supporting bolt a little tighter. On this note, as I think I mentioned, somebody has previously re-threaded the tool post bolt on the top-slide for M10. I don't know if the original thread had worn or whether there was another reason.

Brian, when you say this, do you mean the spindle wont accept ML7 hardware as it is? I was under the impression that, given the thread form and dimensions, ML7 backplates etc. would fit. May I ask what the difference is?