ML7R/Bearing ‘Rumble’

[john fletcher 1Participant @johnfletcher1]

If any one else is considering replacing the head stock bearing check with RS Component their price is half other suppliers and delivery if free. John

[julian atkinsParticipant @julianatkins58923]

hi jonathan,

in Brixton, 28 Wanless Rd SE24 you have the S.M.E.E. headquarters where regular meetings are held plus fully kitted out workshop attended by many of the great and good in the ME world. can i suggest you contact them with a view to joining plus an appeal for help with your lathe.

cheers,

julian

[jonathan olleyParticipant @jonathanolley64724]

Thank you all for your kind advice and time spent offering it. I have now ordered a set of bearings from Lathe spares and a new wick from Myford (£12???).

The SMEE is a really good idea so I've enquired about membership.

I'll let you know how I get on!

Thanks again, Jonathan

[Dennis WAParticipant @denniswa]

Jonathan,

In 2012 Darren Boden's phone number was advertised as 07790364189.

Cheers

Dennis

[AjohnwParticipant @ajohnw51620]

A machine tool reconditioner may be able to help. I'd be surprised if there isn't one around London somewhere. Often the easiest way to find them is to search for slideway grinding. Personally though I would want to be sure that they had done this sort of thing on a Myford before. There is also a chance that the cone bearing will need scraping in.

If you decide to have the slides reground at some point I would suggest stating another thread. Myford offered a very reasonably priced service in that area and I feel it was also worth paying for a saddle refit. I don't think they used the technique usually used – grind the bed, saddle and then use stick on material to restore the sizes. That approach might not suite a Myford but maybe some one has had it done and all is ok.

John

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[jonathan olleyParticipant @jonathanolley64724]

Hi, I finally got up enough courage to attempt an investigation myself (Thanks Eric), and this is what I discovered.

The tapered journal was adequately lubricated and the wick only slightly worn. The rear bearings would seem to be in serviceable condition though the set on the far left is noticeably more worn that the set on the right. I am yet to remove them and won't until I receive their replacements. I will replace the wick though it is almost certainly unnecessary.

What I see is that %40 of the front portion of the tapered bearing is worn and the other %60 is unworn, at all in fact. i can still see the scraper marks on the bronze. Was this a poor fit in the first place? Or is this normal wear and tear??

Here are some images…Any comments or suggestions gratefully received. My intention is to replace the ball bearings and adjust the spindle. If I cannot obtain Zero (or close to) run-out on the nose I shall seek further advice and/or shell-out for a new spindle/bush etc or in other words £200 plus the faff of 'fitting', which of course I know nothing about. Funnily enough, my uncle is a retired machine fitter, dealt mostly with industrial production lines for Dunlop…only thing is he lives in NZ….So unlikely to want to pop over for a cup of tea and a Q&A.

Cheers, Jonathan

[Michael GilliganParticipant @michaelgilligan61133]

Posted by jonathan olley on 12/03/2016 23:20:45:

Hi, I finally got up enough courage to attempt an investigation myself (Thanks Eric), and this is what I discovered.

… Was this a poor fit in the first place? Or is this normal wear and tear??

.

Jonathan,

To my eyes, it looks like the spindle was poorly fitted … Perhaps Tea-Break interrupted the scraping.

Check the taper on the spindle [the actual angle doesn't matter, but it must be constant] … Then, if it's OK,  get yourself a good bearing scraper and some blue.

MichaelG.

Edited By Michael Gilligan on 13/03/2016 00:05:38

[John FieldingParticipant @johnfielding34086]

From the pictures I would say the bronze bush is toast! The spindle is very hard steel and hardened even more by heat treatment, so it will be able to polish it or even a tiny bit of grinding by a company who specialise in this type of work.

If it were my lathe I would bite the bullet and buy a new bronze bush and have the spindle touched up. Scraping isn't an impossible task to do at home if you take it slowly and know what you are doing. But pictures can sometimes lie!

I have never had to press out the bronze bush in a Myford but I think it could be done in situ with a big bolt and some spacer collars machined up to fit the bush exactly. It will probably need a fair bit of Sunny Jim to get it out and the new one into place.

[Michael GilliganParticipant @michaelgilligan61133]

Note: Scraping the front bearing is, of course, much easier if the the headstock casting is on the bench … see photo 15 here.

With the headstock on the bed; you will be working upside-down at times.

… Viability probably depends on how much material needs removing.

MichaelG.

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P.S. … This short article is small but perfectly formed.

Edited By Michael Gilligan on 13/03/2016 08:17:46

[KWILParticipant @kwil]

Looks more like it has been running dry or over tight. The trailing edge of the oil slot at the out end is crumbled (dragged) away.

Once the new rear bearings have been preloaded with the front bearing clear (ie spindle to the right), move spindle to left with the clamp rings and C spanners until you can feel the front bearing begin to drag and henpush the spindle right using the C spanners as per the Myford Handbook Instructions to get the correct running fit.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by KWIL on 13/03/2016 09:29:31:

Looks more like it has been running dry or over tight. The trailing edge of the oil slot at the out end is crumbled (dragged) away.

.

Quite possibly; but [surely ?] if the bearing was properly 'fitted' there should then have been 'contact' over the full length of the bearing.

MichaelG.

Edited By Michael Gilligan on 13/03/2016 09:40:29

[AjohnwParticipant @ajohnw51620]

It looks like one of two things to me. Bearings not correctly adjusted which means that the spindle will tilt during turning more than it needs too causing more wear to the front of the cone and or some one has had a go at scraping the cone in. The tilting effect is always there to a certain extent on lathe bearings. Eventually they tend to wear oval what ever type they are. Allowing them to run too loose just increases the wear rates.

Chances are that some one has cleaned the oil way edges up with a file.

Personally I doubt if myford scraped these bearings on new lathes. It would make a lot more sense for them to make the parts accurately in the first place or use some sort of jig to correct things. Bearing scraping ideally just needs to be a bit of extremely light relieving. No one told Myford that when they made the first batch of phos bronze ml7 bearings which makes me think they had never really scraped anything in. The allowance they left was nothing short of insane and when they corrected that they wouldn't supply me with another set for free or even at a discount.

If some one actually has had a go at scraping the bearing in they probably used way too much blue. I'm not sure that they have though as it tends to leave an evenly dimpled surface but the high spots would soon wear off.

Reading Michael's link there is another and to me more usual way of sharpening a 3 square shaper. Hollow grind the faces but the scraper has to be kept closely tangential to the wheel right up to the tip. Then it's honed forming a sharp rim at the edges. This way they can be rehoned easily and quickly until too much of the hollow grinding has gone.

Bearing scraping isn't that difficult a thing to do if done slowly and carefully. Looking at the marks on the spindle I'd guess it's pretty close at the moment and the main problem might just be that it was too loose. The problem with removing a lot of material with a scraper is maintaining alignment. Not just in lathe terms. In this case the alignment between the cone and the rear bearings. Having the head out vertical on the bench would make a lot of sense as it might get round the spindle tilting under it's own weight as the work is done.

When the new bearings are fitted that the time to get the blue out and see what's what. That will need a lot of careful adjustment of the rear bearing each time it's checked. Or of course adjust and turn etc and see what happens. They should still have some super 7 spindles – maybe. I requested one and was told they had never ever supplied one but they did make a batch later. My main reason for wanting one was damage to the morse taper which looked like it had been reamed several times so little scope for more. My Boxford appeared on ebay so I never bought one.

John

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[Michael GilliganParticipant @michaelgilligan61133]

John,

Spindle and Bearing are both listed **LINK**

… But I don't know if these are ex-Beeston items or newly manufactured.

Given the cost [not unreasonable, but significant], I would have a go at restoration if it was mine.

MichaelG

[LambtonParticipant @lambton]

John,

"It looks like one of two things to me. Bearings not correctly adjusted which means that the spindle will tilt during turning more than it needs too causing more wear to the front of the cone "

I agree with your reasoning however I am sure the scraping at the rear of the bush is the original Myford work.

My reason for saying this is my Super 7 has exactly the same scraping type of marks and I know for certain sure that no one has ever touched this bearing since it left the factory.

Before CNC machining became the norm hand scraping of bronze bearings for precision fits was standard engineering practice which not only produced a high standard of fit but also left the small depressions caused during the scraping process to act as mini oil reservoirs.

Eric

[AjohnwParticipant @ajohnw51620]

Posted by Michael Gilligan on 13/03/2016 12:25:04:

John,

Spindle and Bearing are both listed **LINK**

… But I don't know if these are ex-Beeston items or newly manufactured.

Given the cost [not unreasonable, but significant], I would have a go at restoration if it was mine.

MichaelG

Me too Michael but I wish I still had the email they sent me offering a spindle – price is up but it must have been at least 15 years ago and probably a fair few more. One thing I would say is that if they still offer the bed regrind and saddle refit which has to include some grinding to be of any use do take them up on it. However the prices may well be a lot more than it used to be. It made me wonder why there are so many clapped out ones about.

Scraping – to me the photo's look like that in one direction and not like that in the other. The phos bronze has worn and that wear will have gone somewhere including any off the spindle causing more elsewhere.

Bearings are interesting though. Talking to people who haven't been with us for a long time now about periods when plain bearings were more common they are the best – just straight parallel ones as all others have complications and the first job on a new lathe or when new bearings have been fitted is to make the next set. Also a jig for boring them out by hand wasn't that uncommon. Scraping literally being for relieving ones that are very slightly tight. My bearing scraper made by me during training for that sort of thing has a blade around 2 1/2" long and a handle around 9" long. The design probably dates back to the early very early 1900 based on ones used way before that. I'd wish anybody luck removing anything other than minute amounts of material with it. I had to buy a huge thing for the ML7 bearings I mentioned. Oddly my father had a similar scraper from his training days. Re sharpening had reduce the blade to under an inch long.

People seem to think CNC is the bee's knees and forget that very high precision work was made on most types of machines but slowly but surely that area moved over to grinders. Shapers are an interesting example of that. A decent one will produce surfaces that wouldn't benefit from scraping at all.

John

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[John FieldingParticipant @johnfielding34086]

Talking about scraping bearing surfaces.

I did do some scraper training as an appie, but not much since then. However, in the 1960s I was invited to see an old Lancashire cotton mill engine in a factory (in Burnley IIRC) that was about to be demolished. I think Fred Dibnah dropped the chimney later, before he was famous.

The engine was installed around the middle of the 1880s and had worked almost continuously until the demise of the cotton industry around the mid 1950s or so. So it was about 70+ years old. The interesting thing was the crosshead slide. This had been made as part of the bed casting and had been "machined" by chipping out with chisels along its length and breadth and then hand filed and finally scraped to flatness. You could still see the tiny scraper impressions made all those years ago. The stroke was about 6 foot and the crosshead was about 12-inches wide. So around 6 or more square feet of cast iron had been hand filed and scraped.

I got hold of an old engineering book and looked up how they did it before the days when milling machines were in common use. Seems the scraping was commonly done by hand by two men who worked together and a gauge plate of flat cast iron about a foot square was coated with soot and oil and then rubbed on the surface to show the high spots and then the fitters went at it with files and scrapers. It must have taken days of work to get it flat over the whole area. Thankfully we today have milling machines and grinders. But you have to take your hat off to those men in bygone days, their work was still evident after millions of sweeps of the crosshead over all those years of running. They don't make them like that any more!

[Martin KyteParticipant @martinkyte99762]

I would agree with the bad adjustment theory of Ajohnw. To much clearance on the front bearing would cause bearing wear to the front of the bush when the spindle is loaded. I would have expected the wear to be upper part of the bush towards the back of the lathe although if there was excess clearance at the front it would tend to run dry much more quickly. This could exibit the signs as shown. Be interesting to see the whole circumference of the bush.

I don't fancy your chances of getting the old bush out though. Re-scraping would be my first choice.

regards Martin

[jonathan olleyParticipant @jonathanolley64724]

Hi, the latest so far; rather than have my lovely ML7R in pieces, I thought I’d put it all back together before I forgot what’s what and got busy with some other distraction…and during the process, adjust the spindle as per the instructions.

Success! (sort of), I’ve managed to adjust the spindle to two tenths over two thou’ of run-out which if you remember is better than the original reading of over eight thou’ of R/O…!

As you can imagine I’m very happy, despite it not being an acceptable tolerance, however it will do for now or at least until I can persuade someone to come and service it professionally.

To that effect I've recently (last two weeks), I've been trying to contact Darren Boden, the ex-Myford engineer, who for a price, would come out to service a Myford lathe. After leaving a voicemail and sending a couple of emails I'm yet to receive any sort of reply, his phone is never answered, just goes to voicmail. He could of course be on holiday but I just wondered if anyone had had recent contact with him and if he's still running his business? Would be good to know so I can try another avenue.

Thank you all for all your technical advice, whimsy and support.

Cheers, Jonathan

[AjohnwParticipant @ajohnw51620]

The reason I have my doubts about scraping to any significant extent on this type of bearing is maintaining accurate alignment of the thrust bearings at the back. Cosmetic scraping which I understand has been called feathering maybe.

I just can't see some one adjusting the rear bearing each time the scraping is checked but was prepared to give it a go if needed. Just maybe it might be easier if there was something available to replace the rear with a sleeve to maintain accurate alignment.

Out of interest I have seen a scraper at work on a bridgeport miller – all done by feel when the slide is moved by hand.

John

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[LambtonParticipant @lambton]

John,

"I just can't see some one adjusting the rear bearing each time the scraping is checked "

Nor can I but Myford used a dummy rear bearing whilst scraping the front bearing. This dummy one was presumably a plain bearing that was a good sliding fit over the spindle.

Eric

[Martin KyteParticipant @martinkyte99762]

I concur with Lambton regarding the dummy bearing. I went to an open day at Beeston not that long before Myfords changed hands and spent some time talking to their head fitter who was demonstrating the scraping of headstock bearings. He used a Bush to support the rear of the spindle when testing with micrometer blue. Simple to make if you take your time to get things well and truly concentric and a nice snug but running fit on the spindle. The headstock needs to be removed and stripped of everything else to make it reasonably light to handle. They used the tumbler reverse stud bore to take a suitable stud on the end of a square section. There is a cross threaded hole to enable this to be clamped at any angle. This way you can hold the headstock in a vice at any rotation in order to scrape and see at the same time. As you have an un-warn section your spindle should start off true at least. Might be an idea if you could get some sort of idea of the amount of wear on the front section maybe by feeler guage when the spindle is hard back against the back portion.

regards Martin

[AjohnwParticipant @ajohnw51620]

I did mention use of a bush. I would also suspect that spindle needs to be vertical when tying it with the blue.

John

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[Martin KyteParticipant @martinkyte99762]

Oh, also maybe you should consider either buying a new spindle and fitting your bearing to that (pricey) or a second hand headstock and spindle assembly and doing a recon job on that. (probably cheaper).

With the second option you get a spare spindle to act as a nose thread gauge when you are making accessories to fit.

Martin

[Martin KyteParticipant @martinkyte99762]

Doesn't need to be vertical just tight against your scraped surface. The idea is to slowly and evenly remove material around the circumference of the bearing and keep the back (unworn surface) looking good without getting distracted by the front.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 13/03/2016 08:03:35:

Note: Scraping the front bearing is, of course, much easier if the the headstock casting is on the bench … see photo 15 here.

.

Just in case we missed it ^^^

MichaelG.

[Author]

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