Myford Super 7 at SRS for only £395

[Bob McParticipant @bobmc91481]

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

[Bob McParticipant @bobmc91481]

Back to to pulley Dept…

re-fitted and new belts.

Other side..

[Dave WoottonParticipant @davewootton]

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

[HopperParticipant @hopper]

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.

[Phil H1Participant @philh196021]

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

[Bob McParticipant @bobmc91481]

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…

[Bob McParticipant @bobmc91481]

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.

[HopperParticipant @hopper]

Great stuff Bob.

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

[Bob McParticipant @bobmc91481]

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.

[HopperParticipant @hopper]

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.

[Bob McParticipant @bobmc91481]

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.

[HopperParticipant @hopper]

Nice to have the reversing instructions. You could fit a reversing switch. You can't machine in reverse as you say. But handy if cutting metric threads to return the carriage without undoing the half nuts. Thats all I've ever used mine for.

[Bob McParticipant @bobmc91481]

Thanks again Hopper & all…

I think I have just about covered it now, there are a couple of things to do but I am already thinking of my next project… I did have thoughts of making a minature version of this lathe … I saw one on i/net some time ago and it looked amazing and claimed to be a working model… well its a thought anyway and I have got all the details at hand!

So just a couple of pics to show what it was like and as it is now..

Thanks…Bob.

pp

[Mike HurleyParticipant @mikehurley60381]

Certainly looks the part now Bob, great effort! Mike

[Dave WoottonParticipant @davewootton]

Great job, the lathe looks fantastic, an amazing transformation into something really useful. A miniature lathe sounds an interesting project, years ago there was someone building a scale model Drummond round bed treadle lathe, it was shown on one of the club stands at the old Wembley exhibitions, every year it used to advance a bit more but I never got to see it finished and have never seen a reference to it anywhere. About 8" long and very nicely made, anyone else remember it or know what happened to it?

This has been a most interesting thread, thanks for posting.

Dave

[HopperParticipant @hopper]

It's a credit to you. Unbelievable when you see the before and after pics side by side. Well done!

[Phil H1Participant @philh196021]

Bob,

That looks like an incredible transformation from here. How much did it cost in Scotchbrite? Serious question…. what was the cost for paint and parts etc? That is well worth knowing for others.

Phil H

[duncan webster 1Participant @duncanwebster1]

Posted by Bob Mc on 02/05/2022 20:08:37:

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

No-one else has got back on this so here's my 2 pennyworth. I'd use that switch to control a proper NVR contactor hidden elsewhere.

[Bob McParticipant @bobmc91481]

Thanks everyone for your comments and advice…

I will be having a look at Duncans suggestion of a contactor…, Phil asks about costs and I must say I had a few lucky streaks … first SRS seemed to have forgotten about delivering the beast and when I contacted them they were most apologetic….and more importantly waived the delivery charge..!

The next lucky break was the topslide and cross slide handles/threads and bits, which were completely locked up with rust, and looking on ebay both were being advertised for £50….and in quite good condition..so that was a done deal..

The leadscrew was around £45, but delivery about £40 … not so lucky on that one … I realised afterward that by using the un-threaded half of the original LS which fits into the change wheel housing I could have gotten away with a shorter length of purchased Acme thread and perhaps got a better delivery option.

The paint and thinners was around £40 and this is the replica Myford paint … I hardly used a 1/3 of it .. and if I were to do it again I would go for ordinary spray paint.

The belts were from Myford at about £14 I think but I could have probably gotten cheaper ones, however they were the proper ones advertised so no messing about.

Well all in all it comes out as a Super 7 with new leadscrew and a complete overhaul at ~£600 … I don't know if that is a bargain or should have just bought a refurbished one, at least I know its in good order …. and to be honest it has kept me entertained for a couple of months and was a project I have always wanted to have a go at.

To sum up… I knew I was taking a big risk with this and I was lucky that the bed was in reasonable condition and had not been re-ground, my advice if you are thinking of having a go is to try and see the item itself in person.

Now what the … am I going to do with two lathes…! rgds… Bob.

[duncan webster 1Participant @duncanwebster1]

Just realised nvr won't work with an on/off switch, but contactor will

[Bob McParticipant @bobmc91481]

Hi all again…

Belated thanks for clearing that up Duncan..

Just a note in case anyone else has had this problem..

The lathe is doing quite well and I took Hoppers advice and fitted a switch to change the rotation of the induction motor as I am in the process of making an experimental delrin leadscrew clamp, however I noticed when manually moving the saddle using the leadscrew handle that there was a definite heavier drag when taking the saddle towards the tailstock end.

After taking the apron apart I found that the top leadscrew clamp gib adjustment screw… (the one hidden under the leadscrew protection cover top screw)… was not pushing the gib in, consequently only the bottom half of the gib was making contact with the clamp dovetail.

Further investigation showed that the 2BA thread for the screw had not been cut all the way through so it was doing nothing…

Problem solved. Bob.

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