Myford Super 7 at SRS for only £395

Saddles wear on the underside at the ends where they collect abrasive material from machining. Usually, the headstock ends are more worn. This causes the face to be convex and so shaped like the rockers on a rocking chair. It's likely that it would blue up quite well but that doesn't mean it's mating with the flat way just that it's printing blue like rolling a fingerprint. If your ways are worn, it's likely that you'll find double the wear in the underside of the saddle.

BobMc you're doing well but you should make sure that you never rely on one set of measurements when looking for wear if you have a means of cross-checking. You chould check your measurements by stoning the front machined face on the underside of the saddle lightly to remove any burrs then running a surface guage on that face with a dial gauge on the ways. That would have been a set-up face for the original machining of those ways.

You're right to be concerned about the saddle height being lowered. It will cause the weight of the saddle to be carried somewhat by the leadscrew and might cause finish issues with your work. You might well be able to skim the bottom mating face to bring the apron up, but don't try to do this on a machine with powered cross-feed or it'll cause the cross slide gears to bind.

Thanks for your post Peter,

Yes I did actually stone the underside of the saddle, it was one picture I didn't take and I can see your reasoning regarding cross checking.

If I understand you correctly the check I made was to blue the ways and move the saddle, I presume that would do the same job?, I also set up the milling operation so that the saddle surface was parallel to the saddle/apron interface surface pic below.

It looks like you have put a parallel on the worn way and are indicating off the parallel. There is a risk by doing this that you will find one end very low and the other end the highest point because it has teeter-tottered one way on the centre high spot. Blueing the ways and moving the saddle carries the same risk. When you take this sort of measurement, always hold down one end of the prism with the indicator on it, then press down the other end to make sure it doesn't rock. Of course since you have milled the underside by indicating the un-worn face then you will already have compensated for that. Hopefully you will have taken great pains to avoid clamping stresses whilst doing the milling it takes very little milling error to require a lot of scraping to correct, as I have discovered in the past.

How are the underside ways now Bob? Still in as-milled condition or did you then scrape them?

Thanks again Peter for your post which is much appreciated as this project was at about the limit of my engineering abilities and equipment.

I did make a custom fixture for the milling operation and supported the saddle using the two surfaces of the cross-slide, hopefully this would not have put too great a stress that would bend it out of shape whilst milling.

I used the saddle/apron interface as a datum surface which was the only surface available to set the work up on, I was contemplating scraping the surfaces after but opted for a stoning as my understanding of having a scraped surface is that a flat surface is needed to bear against it..

The motion of the saddle on the ways is quite smooth and there does not appear to be any rocking, or lateral movement with the gibs set up.

Again your advice is much appreciated and if there are any anomalies I would rather it be picked up now before I set the lathe on a solid foundation.

Milling set up..

There is no problem running two scraped faces against each other Bob and it would be preferable to using a stoned face. The upper face of a pair will benefit from heavier scraping or 'oil flaking' so it has pockets to retain oil. You wouldn't do the lower face such as your lathe bed because then the pockets would hold dirt for the saddl e to pick up as it travels over. Your scraping on the bed is not deep eough for that to be an issue.

If you have confidence in your bedway being straight and true you could fix it down and level it, then blue it up and use it as a reference for scraping. Be prepared if you're going to do this because although you've made an admiarble job of milling the bottom flat and certainly improved the geometry even after stoning, it would print up poorly when blued. They always do it's just the way things are.

I don't know what your location is but I could certainly give you some pointers and practical assistance if you're near me in Kent and in fact if you can get to Essex I did just discover that the guy I have bought several straight edges off (the only source of new cast iron references in the UK now afaik) will be running a week-long scraping course next month. If anyone is interested I can fish out a link.

Thanks again Peter,

I would indeed like to be educated in the art of scraping, unfortunately I live in Cheshire so thats a bit too far for me!

I will now press on with the post and show the refurbishment of the pulleys...and a few pics of the lathe again, I don't know what it is about the old Myford but they have a pleasing curvy shape unlike the new lathes of today which to my mind look like that could have been bolted together from sheet steel.

You may notice my on-off switch housing which I thought would complement the rounded change wheel casing, the one thing I am looking for is a 'snubber' circuit since there is a definite electrical flash when the switch is turned off.....anyone point me in the right direction..? it has to switch off the induction motor.

Pulleys..

cleaning up.

p

Yes that is one of the things I like about the old Myfords and before them the Drummond M-Type. The ML7/S7 series released in 1946 was one of the last vestiges of Art Deco styling that peaked just before the war. Would have been designed during the late war, still to pre-war thinking to some extent.

The modern square block machines just don't have that kind of style, and look as if all those sharp angular corners and edges would be murder on hands and knuckles. If I bought a new Chinese lathe, as good as they doubtless are from a practical standpoint, first thing I would have to do is take an angle grinder to that square boxy tailstock casting. And then probably carry on along the carriage and heastock!

Your old girl is looking great in the latest pics. A far cry from your starting point. Shows what can be done with a pile of rusted "scrap".

Pete,

Thanks for that explanation. I was assuming that the underside of the saddle was checked for flatness first but the rolling of a fingerprint is a good way of explaining the possible snag.

Bob, that looks like it has cleaned up very nicely. Slightly better than a boat anchor now isn't it?

Phil H

It does catch people out. For small items like cross slides you put them on a flat piece like a surface plate and bang down on the four corners in turn with your hand. If it clacks there is clearance below. For longer parts just scraper the middle - your blue spotting will gain a patch of no contact in the middle and you just keep scrparing wider and wider until the blue reaches the ends.

Thanks Pete, Phil, Hopper...

Yes I don't know what it is about curvy features that have given me great pleasure over the years....

anyway as I was saying.... The Pulley Department next..

I took the whole clutch assembly apart to get to the pulleys, later on I thought to read any write ups on the clutch mechanism... I can't remember where it was written now but there was a dire warning about removing the clutch spring which can be a lethal excercise....too late now and I began to wonder how the blazes was I going to get it all back together.

I solved the problem by making a fitting to clamp over the end of the clutch spindle, this allowed me to force the spring whilst screwing the grub screw on the other end, it is a 22mm brass plumbing end stop cap just opened out a little to fit over the spindle, the end plate tapped and a bolt fitted which would force the spring down, worked a treat...

pic of fitting.

pp

Back to to pulley Dept...

re-fitted and new belts.

Other side..

Hi Bob

This is a very interesting post, you're doing a great job, I remember the original post for this lathe, I'm so pleased it went to a good home. You will end up with a very nice machine.

Sadly I just missed out on an Acorntools shaper in similar condition which I was itching to restore, it went for scrap along with a couple of other machines due to eager property developer types, such a shame, been after it for ages.

Please keep up the posts.

Dave

Good bit of ingenuity there on the clutch spring compressor tool from a plumbing fitting. The lathe is looking good. Unrecognisable from a few months ago.

Bob,

Another way of looking at this is that somebody must have used the machine before it went red with rust. So any correction to the bed and slideways might not be perfect but it will probably be better than it was.

By the way, I have noticed you are slacking a bit. When are you going to paint the lettering on the belt guards?

Phil H

Thanks Phil, Dave, Hopper, Pete..

..posts very much appreciated.

It can sometimes be a daunting task to make decisions that could be very costly mistakes, the leadscrew is one example where I just had to bite the bullet and go.

When I examined the leadscrew it was part rusted up, and not worn enough to be un-useable but not really what I wanted; the other problem was that the handle end was slightly bent, which probably occurred during delivery, I put the leadscrew in my Atlas lathe and tried to correct it.

Yep... I managed to get it straight using a number of supporting blocks and a G clamp...however I was not happy, I decided a new one was required..... I looked for a new one but there were no S7 leadscrews available as new...other Ls's for the ML's may have fitted but when I saw the price...!! I can't remember exactly as my mind did a somersault ... think it was about £300 ...!! and that is without delivery, ....!

Some pics of old leadscrew being investigated.

The leadscrew removed, if you look closely the name of the company it came from is 'Holpack' .. I think it might be an American company? anyone know..?

Rust on LS .

Handle end bent...

Leadscrew problems.

I found a supplier for the Leadscrews 8tpi Acme thread and the plan was to purchase only the length of the threaded part needed, this is about 3ft long, the un-threaded end which fits into the bearings at the headstock end is ~18 inches long, and as there was nothing wrong with this part of the original bar I decided to cut it off and use it.

This saved me quite a bit of cash as the purchased piece of acme bar was not only 18 inches shorter but I wouldn't have to turn down this long length which would be quite wastefull.

The main problem being centreing up the original un-threaded length to the new Acme bar, which after much preparation was accomplished by machining the original un-threaded end and the Acme thread so as to fit a prepared socket concentrically; use of the Elephants foot and the four jaw are essential to this operation.

Another problem raised its head when I examined the purchased Acme thread, it had a 20 thou bend over its length, this would have to be sorted out and after much head scratching I decided to fit the bars together and use a method I had already used for my Atlas lathe leadscrew which was just a stainless steel threaded rod with a similar problem.

So with the bars fitted together and assembled to the lathe bed I used my method of precision bending which removed all traces of the bend.

I think the problem of bending when a long bar is threaded is caused by stresses in the material being removed which would normaly keep the bar straight...well that's my opinion, nevertheles the result of the excercise is that the leadscrew is quite straight and does not give any indication of lateral motion when driving the saddle.

The machining of the Acme threaded part for the handle fitting and its associated threading for the nut requires the Acme bar to be supported externally to the left of the headstock to minimise any whipping about. This was a consideration I made in setting up the workshop originally, to put the press drill to the left of the lathe so that any long bar material could be supported with the drill table being adjustable for height.

Fitting the two bars together.

Bar being supporded with drill table.

Great stuff Bob.

Who did you buy your Acme threaded rod from? It seems increasingly hard to get these days.

Thanks Hopper... I got my Acme thread from Kingston Engineering services...Hull ... would ask if you could have your own courier as their charges seemed a bit over the top...

Phil...yep I am a bit lax in the paint department, will get round to doing the lettering one day..

Headstock spindle.

The front bearing is cone shaped rotating in a bronze bush, on examination I noticed that there were defininte 'ripples' along the surface of the cone, not easily seen but could be felt with finger running along it, there was also a raised portion at the front end where the bronze bush ended its connection with the cone.

I tried to feel if there were the same ripples on the bronze bush but to my surprise it didn't appear to have any problems.

Putting the spindle in the lathe is quite easy, I fitted an M2 - M1 adaptor and the open end of the M1 used with a live tailstock centre.

I used a flat stone to take off the raised section and again on the cone area with the spindle rotating at a slow speed, the stone was moved against the bearing cone area to and fro and with a constant supply of lubricant in the form of white spirit.

The theory being that the form of the cone would be preserved so long as the stone was kept held in place by hand with equal pressure over the surface whilst sliding the stone, I had looked into the process of lapping and the question of embedded particles should not be a problem with hardened steel.

A good washing in hot soapy water then ensued, I also used an ultrasonic cleaner but I don't think it necessary.

The next stages of lapping required using emery on a flat steel bar going down in grit size, and the same processes repeated. Finished off with Brasso on a cloth and got a nice shiny finish.

Testing the bearing in the bronze bush with blue and turning 1/4 turn showed a complete surface connection. On running the lathe when completed everything appears to be running true and free.

I will at some time be having a look at the bearing again to make sure everything is ok.

Some pics below.

Nice work with the slipstone there. And the surface of the bushing was good enough to use as is? Which proves the old adage that bits flake off the hard component and embed in the soft one, making a nice lap.

An easy way to highlight that raised lettering on the bdd and belt and change gear guard castings etc is to use a small paint roller, about two inches long and three quarters of an inch in diameter. Sold at hardware stores for cutting in the corners of ceilings and walls when painting your house. Just roll it lightly over the letters once and job's done, without the splotchiness (technical term) I always get when using brushes of carefully folded and balled rags etc. It leaves a nice straight painted edge where the letter falls away. And takes about 30 seconds.

Thanks again Hopper...

I didn't know about the flaking...but am going to give it another look over when it gets bedded down, thanks for lettering idea....I have an aversion to painting brought on by a certain person constantly nagging me to do some decorating.

Motor..

The motor looked as rusty as the rest of the lathe but the suppliers SRS had given it a PAT test with certificate and it did run but it had a problem as it kept re-starting, I took it apart anyway.....the starter switch has a centrifugal mechanism which was jamming, a good clean up and a bit of grease sorted it out although be aware that the grease could fly off into the switch if overdone.

The capacitor box was a bit bent but the cappi looked perfectly ok so re-bashed the box and sand blasted ... it was a bit dire... and made a gasket out of some thin leather I had hanging around.

Gave it a good clean up and re-painted...now starts up and keeps up quietly....forgot to take picture of the done job, you might be able to see a bit of it in the completed photos.

I was surprised to see that someone with forethought had put a note in the connection box showing how to reverse the motor...thats a great thing to do although could have mentioned that chuck might fly off.

This is what it looked like.

The connection box.