Myford Mk1 Super 7 restoration

[MortyParticipant @morty]

Hi there!

Now, where was I………

Ah, yes, time to get the headstock off:-

Loosen capscrew on locking collar and remove, undo grubscrew in back gear and drift out quill to the right ( must get some new heads on My mallet, only had it 40 years……….

(Don't forget to catch the Woodruff keys…..)

60 Years of crud in there, but managed to find the 4 capscrews and remove them ( very tight! ), and lift the headstock clear:-

Bed wiped down for inspection and carefully lifted off and put to one side:-

A few 'manual' parting off marks on the top off bed but I have seen worse!

Wear variation measurements as follows (taken at 5 points along bed):-

1:- Total width across both bedways- 0.011 mm

2:- Horizontal width of rear bedway- 0.080 mm

3:- Horizontal width of front bedway- 0.006 mm

4:- Depth of vertical shear front of front bedway- 0.087 mm

5:- Depth of vertical shear rear of front beadway- 0.214 mm

6:- Depth of vertical shear front of rear bedway- 0.164 mm

7:- Depth of vertical shear rear of rear bedway- 0.064 mm

I am reading this as the worst wear is on the 2 inside vertical shears.

Not being very knowledgeable about these matters, could somebody set Me on the right track here as to whether the bed is in need of a regind or is it servicable?

(I'm not sure if all the above measurements are required, opinions vary, so I took them all anyway!

Next job is sort the rising blocks, drip tray, switch removal and clean up the cabinet ready for stripping / re-painting.

Thanks for looking in!

Cheers, Pete

[Werner HabbelParticipant @wernerhabbel11353]

Hi Pete,

my name is Werner and I am from Germany. I own an eraly S7 with gearbox as well. Serial no SK3853 on the bed and 1184 on the gearbox. The gearbox unfourtunately has the soft gears.

In 1995 on holidays in UK I visited Myford and asked for a repair because the metric threads didn't work. I had no appointment and the repair was done within one day. Lovely

The S7 lost its precision so I am very intersted in your report and looking forward for the continuations.

Werner

[Dave WoottonParticipant @davewootton]

Hi Morty

There have been a small series of articles by Peter Barker on checking for wear and rectifying in MEW magazine for the last few months. They are aimed at the ML7 but are well worth reading, there are some clever ideas in there.

Dave

[SteviegtrParticipant @steviegtr]

Hi again Morty. Look this guy up on youtube. He renovates Myford lathes in detail. Everything you need to know. He is slow but methodical.

Sven

Steve.

[MortyParticipant @morty]

Hi there!

Sorry for the lack of updates, stripping the cabinet etc. at the moment not a lot to see, raising blocks responded well to paint stripper and wire brush, but on the tray and cabinet the stripper had no effect! ( thinking of something a bit more invasive, such as a small tactical nuclear weapon!!  

Seriously, I've sent for a stripping disc which should arrive during next week!

Werner – It is nice to hear of the service that You received at Myford, good to hear that customers were looked after!

Looking at ideas at the moment to improve the bed (see below )

Dave – I will search out the articles You mentioned, well worth a look.

Steve – I had a look at Sven's videos before, He does go into the details really well!

I think I am going to clean up the bed for now and get it going again, what I was looking at was changing over to a wide guide set up as detailed in this thread:-

https://www.model-engineer.co.uk/forums/postings.asp?th=110700&p=1

This would be something I could do by just removing the saddle, but would need a miller (J.A. Radford's method),

so It would have to wait until the workshop is completely set up.I

Thanks for.the replies, I will put some progress pics up on the next posting.

Cheers, Pete

Edited By Morty on 18/04/2020 00:12:47

[HillclimberParticipant @hillclimber]

If the paint is 'stuck' that well on the cabinet, perhaps better to leave it in place, sand it down to provide a key and clean it – and simply paint over it?

Cheers, Colin

[john fletcher 1Participant @johnfletcher1]

I has the same early type Super 7 with early type gear box. I like Werner found that some of the internal gears had teeth missing, on contacting the original Myford they said, they no longer had spares for the early type gear box. I looked in HPC gear catalogue and found they had them on stock, unfortunately with a bigger bore. I bought the gears, increased the bored even more, then shrunk in a piece of prepared bar to fit, and then bored it to size when cool. I hope you don't need this information. John

[MortyParticipant @morty]

Hi there!

Werner:- Sorry, I did not see Your message until after I replied last night, I will Email You tomorrow!

Colin:- I did think of leaving it and overpainting it, but I was not sure if the new paint would react with the old, I like to go back to base metal if possible, plus there are rusty areas to sand out as well. The stripping wheel I have ordered should sort it out OK.

Hi John:- I will have a look at the gearbox a bit closer when I get to it, I did test run it before stripping the lathe down and it seemed quiet and smooth, but many thanks for letting Me know about Your repair, good to know it is possible as I did read that spares were not available for the earlier box. I also hope I don't need the info, but good to know!

Many thanks All! Cheers, Pete

[Werner HabbelParticipant @wernerhabbel11353]

Hi John,

interesting to read about your repair method with HPC gears.
For all metric threads they run over only one pair of gears in the old gearbox. This pair is very worn but could not be replaced during the repair at Myford. The nice fitter who repiard the gearbox explained me what was wrong inside. Furthermore he said that the metric worn gears will "work als long as you live".

Regards
Werner

[Mike PooleParticipant @mikepoole82104]

The screw holes in the motor are original as foot mounting or resilient mounting were both possible.

Mike

[HopperParticipant @hopper]

Posted by Morty on 18/04/2020 00:11:24:

Hi there!

Sorry for the lack of updates, stripping the cabinet etc. at the moment not a lot to see, raising blocks responded well to paint stripper and wire brush, but on the tray and cabinet the stripper had no effect! ( thinking of something a bit more invasive, such as a small tactical nuclear weapon!!

Seriously, I've sent for a stripping disc which should arrive during next week!

Werner – It is nice to hear of the service that You received at Myford, good to hear that customers were looked after!

Looking at ideas at the moment to improve the bed (see below )

Dave – I will search out the articles You mentioned, well worth a look.

Steve – I had a look at Sven's videos before, He does go into the details really well!

I think I am going to clean up the bed for now and get it going again, what I was looking at was changing over to a wide guide set up as detailed in this thread:-

https://www.model-engineer.co.uk/forums/postings.asp?th=110700&p=1

This would be something I could do by just removing the saddle, but would need a miller (J.A. Radford's method),

so It would have to wait until the workshop is completely set up.I

Thanks for.the replies, I will put some progress pics up on the next posting.

Cheers, Pete

Edited By Morty on 18/04/2020 00:12:47

Hi Pete

If you search the MEW index for the series of articles by Pete Barker over the past year or so, you will find a lot more information on Myford bed wear, wide guide, bearings etc etc if you can get back issues or a digital sub.

In a nutshell, old Myford literature on their former reconditioning service recommends a bed regrind if wear exceeds .003" (note, inches not mm) measured in the horizontal plane (ie measuring wear on the vertical surface of the shear) and .005" in the vertical plane. But you could probably get away with a bit more if you are not doing micron-level work.

There is an easier alternative to the Radford and Ganderton methods that does not require a milling machine. It is outlined in the MEW articles. Basically add a strip of gauge plate to the rear carriage surface so it contacts the bed's unworn rear shear. Then just leave the old narrow guide surface as is, sitting a good 20 or 30 thou away from contacting the shear. No need to do the Radford thing and have two contacting surfaces. The factory never did that. They just went (in 1972) to using the rear surface only.

The surface of the carriage that runs on the top of the bed ways can then be touched up with a file and a small scraper made from a file. All detailed in the MEW articles. No need for a milling machine at all.

Looks like you have a lot of wear on the inner vertical shear surfaces. This can also be remedied as outlined in the articles by adding a cutting tool to a vertical slide mounted on the carriage and running it back and forth like a hand-powered shaper. Sounds crude but it has produced an excellent result and a lathe that turns dead true between centres, where the tailstock relies on these surfaces for alignment. So is is well worth doing.

Your measurements posted earlier seemed a little odd in that the vertical depth of the front shear varied so much from front to back. Not sure what is going on there? Depends where the wear is. Could be tailstock caused wear, or if it is in the usual high wear patch about six inches from the left end of the bed ways, it's from the carriage. Could be a bit excessive for fine work if that is the case. Might pay to measure carefully again and do an assessment.

Have fun with your rebuild. It's very satisfying to be able to do precision work on a machine you have rebuilt yourself.

Pete B.

[MortyParticipant @morty]

Hi there!

Mike:- Thanks for the information on the motor mounting, I had not come across this style of mounting on the various Myford S7's that I have seen, so it was a bit of a puzzle, thanks for the explaination!

Pete:- Thank You for taking the time to post this very useful information, I will look into the articles in the MEW index, seems a very good source for delving into the inspection / rectification involved.

I will go back over the measurements again, I have been made aware of the 'shaper' method which sounds interesting.

As I mentioned in My post, I will probably get the lathe back together and run to check the accuracy first, as removing the saddle for any rectification work that does not involve a bed grind is a fairly quick and straightforward job.

Again, many thanks to everybody for replying and advising Me on My Quest!!

Cheers, Pete

[MortyParticipant @morty]

Hi everyone!

Just a quick post, sorry about the lack of updates, still stripping the paint of the cabinet,slow going as I have a few neck problems that cause trouble with My arms, so the drill I am using for the stripping disc gets heavy quick and I'm can only do so much at a time!

Nearly there though, will post some pics in the week.

Take care and keep safe!

Cheers, Pete

[MortyParticipant @morty]

Hi everyone!

Just a quick post, sorry about the lack of updates, still stripping the paint of the cabinet,slow going as I have a few neck problems that cause trouble with My arms, so the drill I am using for the stripping disc gets heavy quick and I'm can only do so much at a time!

Nearly there though, will post some pics in the week.

Take care and keep safe!

Cheers, Pete

[SteviegtrParticipant @steviegtr]

If you are going to spray paint the cabinet then if you clean any rust spots off. Then buy some hi build primer. A few coats & then flat with the sander. More coats if necessary. It is amazing how with the primer you can get a nice even surface to paint on. Regards.

Forgot to say I mean spray gun applied hi build. Not rattle cans. It was about £22 a litre last time I bought some. I have a few spray guns. The one I use for my primer is just a cheap one, it has the 2mm nozzle so you can put good heavy coats on. 

Steve.

Edited By Steviegtr on 10/05/2020 00:43:47

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Morty on 09/04/2020 15:29:37:

Hi there!

Now, where was I………

Ah, yes, time to get the headstock off:-

[…]

 

 

 

A very useful set of ‘real world’ reference images there, Pete

… I’m sure they will be quoted many times in the coming years.

MichaelG.

Edited By Michael Gilligan on 10/05/2020 07:06:13

[MortyParticipant @morty]

Hi Steve!

I'm nearly there now, just the back and bottom to do, I am not going to do the top of the cabinet or the underside of the tray as the paint is intact, and the inside will get a rub down and de-grease.

I'm using red oxide on the cabinet and tray and etch primer on any aluminium castings, will probably use hi build on castings as required.

Hi MichealG!

I hope that My ramblings and digital etchings will be of some use to some poor soul in the future!!

Thanks for looking in!

Cheers, Pete

[SteviegtrParticipant @steviegtr]

As MichealG says keep up the good work. The pictures paint a thousand words so lots more.

There are still a lot of those lathes around, so guess plenty of members can use yours for a good reference.

Steve.

[Peter SansomParticipant @petersansom44767]

I have a Mk2 1958 S7. Did a recondition a couple of years ago. Still have a few bits to do and it missed out o a repaint as we were getting ready to move. Ahave been too busy after the the move to do much.

I had the bed reground. The hardest issue was finding a surface grinder long enough. ground the bed top and tehn converted the saddle to a wide bed. Also fitted taper roller bearings instead of the Angular Contact bearings. If you do the taper roller bearing conversion, make sure that you get bears from SKF, NSK or similar. The Taper Roller bearings are common as thehy are used on a lot of cars. Most are rubbish with too much noise/vibration. SKF have a higher speed rating.

Ended also replacing the bearing in he clutch as there was a lot of noise there. Still habe to replace the Clutch Thrust bearing and the Oilit bushes. I have the parts now, just need time.

Peter

[MortyParticipant @morty]

Hi Peter!

Thanks for the advice I am thinking about doing the side bed conversion, but I am getting the lathe back together to see how the land lies before doing it.

I have a quick ring around about a bed grind, looking at £5-600 mark, I think I might get away with the side guide setup.

I will check the spindle bearings out when I strip the headstock down,they feel alright but if I need to change them I will go for taper rollers, I have always used SKF or FAG bearings, never had a problem!

My S7 is fitted with the early clutch, I have been asked with the information on this and will again check it out when dismantled.

Again, many thanks for the advice!

Cheers, Pete

[SteviegtrParticipant @steviegtr]

Just take it easy with the clutch. It is a cast split ring on the S1 & not uncommon to break in half. We brazed one back together. Still working. But no parts available for that version.

Steve.

[MortyParticipant @morty]

Hi Steve!

Thanks for the heads-up, duly noted!!

The reason for stripping it down was for cleaning and painting, I can get round that by using a 'hairy stick' for both!!

It was working fine when I tested it so maybe best left alone, there is some play in the lever pivot that I will need to attend to.

Cheers, Pete

[Mike DonnerstagParticipant @mikedonnerstag]

This is a very interesting thread to me, as I'm just about to replace the bed on my Myford Super 7 and will shortly be removing the headstock and motorising assembly from the old bed. Do I need to remove the spindle and remove the drive belt to allow the headstock and motorising assembly to be separated?

Mike

[MortyParticipant @morty]

Hi Mike!

To change a belt, You can either pull the spindle , or strip the clutch off, I have tried to keep the stripped lathe in 'biggish chunks' and work on them as separate projects,so I did not want to strip the motorising assembly yet.

( In fact, I cut the belt off as it is being replaced, but needed to move the spindle to gain better access to the headstock securing bolts, expect them to be tight!!!)

The motorising unit just bolts to the back of the headstock with four hex bolts just lifted away when the belt has been removed. I took the motor off first to keep the weight down.

I would just like to apologise for My lack of updates on the thread, My health has been a bit up and down recently, so I have had to limit My time in the workshop.

The cabinet, tray and rising blocks are all stripped and ready for painting, I will post the pics up when I have done 'em!!

Thanks for Your patience, and keep safe.

Cheers, Pete

[Mike DonnerstagParticipant @mikedonnerstag]

Many thanks Pete. Sorry to hear about your health – hope it improves soon, and I look forward to your updates.

Which do you think is easiest: removing the spindle or removing the countershaft? Also, this may be a silly question but… how do you know if your rear headstock bearings need replacing?

Mike

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