BAZMAK-Diary of a Myford super 7b lathe restoration

[bazmak]

Well after selling my 3 myford ml7s I bought a super 7b long bed with the proceeds and decided to start a new thread.With the clutch assy/countershaft and the gearbox there will be a lot more work and I intend to spent more time and effort with this one.Lathe arrived yesterday and I have made a start.According to the seller the paintwork is bad but is supposed to be a good runner.We will wait and see.The leadscrew was described as worn at the headstock end and it is ,so I invisage cutting the leadscrew and reversing as well as fitting thrust bearings.Anyone out there have experience of this please comment.I cut the main drive belt so I could strip down easier and keep the countershaft/clutch and the headstock as sub assemblies rather than have lots of bits at this early,very dirty stage.Will fit a new V belt or link belt.I had a liter of near Myford green but did not like it
and as I have used all the grey decided to go as near as I can to Myford blue.Made a new pair of riser blocks to my standard design but used 75x50 rhs instead of 50 sq. looks more in proportion

 

[goldstar31]

'Morning, Barry!

Initially, I hope that the restoration challenge will be met and overcome.
Whilst I have not 'reversed' my Super 7 leadscrew , I recall others doing it. Again, I recall Martin Cleeve- pegging the thing. So I can comment that 'mine' is joined to the gearbox. It doesn't run right through.
As you have a long bed model, reversing it will not unduly affect its use. I think that you will rarely use the full lenght.

Yours seems to be a Mark2 as mine has the earlier sight glass and the different clutch. Wicks for the Mark 2 are still available from RDG but-- nothing for mine.

Again, you will have a different casing to cover the 2 speed belt. I expect that you know all this, anyway.

As for paint, I settled for the RAL Iron Grey which is 'near' the Myford grey.

Going back to 'mine', I stripped it down and filled the jet wash up with detergent and blasted all the years of gunge and loose paint away and spent £250 on getting it slideways ground and having the underneath of the saddle built up with Turcite. Again, I blasted the gunge etc away and filled the missing paint work initially with an odd mixture of polyester car bodge and a bit of fibreglass resin and then brought it all up with car body green professional filler. Earlier, I did a City and Guilds course in Motor Vehicle Restoration so it was all very straightforward. As far as the other bits like the top slide, I can scrape but would mention that a Super7 has a different spilt gib compared to the ML7. It's actually nicer to do and then adjust. What I did find was that the top where the tool holder goes was badly worn. I did mine in a surface grinder but it is fairly easy to scrape flat after you break the cast iron 'skin' which comes with age.

Perhaps, I've gone a bit over the top with mine but Super7's are being reconditioned and sold by RDG at £2995 and then a gear box 'chines in' for an additional -say- £450. All this does not include even a chuck , faceplate or centre.

It does make the whole project worthwhile or not because I was offered a Murad Bormilathe for a modest £550 and a Murad Antarctica for only £300. I 'm not strong enough to manhandle them any more and again, I'm limited with car insurance to no more than 2000 miles a year.

So Keep posting, you have my full attention

Norm

 

[bazmak]

Thanks for your comments and info Norm. much appreciated.I have had super 7s before including a b but have never taken them apart
Had a couple of tricky moments where the s7 differs from the ml7.Finding out of way grubscrews buried under the gunge.This one is the later
model where the leadscrew goes thru the gearbox. Quick check only revealed one bad point so far.The alum gearbox cover has been broken
but well repaired with a plate and a no of screw fixings.Will try to improve it when I eventually get there.The inside of the gearbox is pristine
but most are as the can handle a lot abuse with the hardened gears.I didn't want a long bed but had little choice and as you say the short bed
is hard enough to handle by oneself.Just been cleaning and painting the bed and I can just about manage it. Like to get it clean and tidy
even if not finished painted before checking and cleaning the ways etc.Managed to get a suitable blue paint off the shelf in the local hardware shop
both as a litre tin for brushing and a spray can for a better finish on the main areas. This one is really gunked up even though it has been oiled thru the
nipples rather than greased. Lots of gunk and brass chips inside the casting. Keep posting. Regards Barry

 

[69002]

Go for it Barry and keep us posted of your progress, I shall be following avidly as I have also just acquired a mk1 super 7b that is in a worser state than yours...but at least my gearbox casing is all intact.

 

[goldstar31]

69002, I've got a Mark1 with a box too.
If you follow the plot-well, mine,- I had mine slideways ground and the very rough underside of the saddle built up again with Turcite. The cost for those items was £250 but simply having the lathe bed top done was probably no more than £50. Of course, this means that it leaves a lot of extra fettling but at least one has a perfectly flat surface on which to make a guide to do the Number 1 shear. Again, it is worth looking at the Number4 shear which despite all the other wear has remained unworn. You CAN utilise the number 4 to move away from the designed 'narrow guide' principle as there is a likelihood of wear at this point.
Myford, I understand changed away from the narrow guide idea in later lathes!

Does this help?

Norm

 

[Nick Hulme]

You just have to love that bed casting with it's depth and rigidity, shame they didn't use the same dimensions for the short ones ;-)

 

[bazmak]

I assumed the bed casting was the same but a foot longer therefore being less rigid. Are you saying that the long bed castings
were beefed up to lessen the risk of twist.It does feel much heavier.Can you clarify your comment please Nick. Also could not figure out
how to do a full stripdown on the gearbox.The large front selector lever when the spline shaft is removed cannot be removed
without taking out the idler gear and I could not see an obviose way to do it.Made do with a part strip down all internals were in
pristine condition so just gave it a clean up.Just meant I coulnt repaint the inside of the gearbox,so not a problem. Incidently
what sort of oil level is recommended for the sump

 

[goldstar31]

The gearbox manual and the lathe manual are both available on the 'net.

What I would mention is that the headstock bearing recommended oil is NUTO32 whivh laughingly is nothing more than what goes into hydraulic jacks- namely ISO32.

Barry, I DID check with the blenders!

My gearbox was different. It had been run on mahogany dust instead old good old straight SAE30

I'll leave the swear words out

Norm

Incidentally an old mate of 91 has pointed out that he has a new book on gearboxes with an emphasis on Myford's boxes. Looks like golddust and he says there is a whole new series of model engineering books just been printed in the UK.

I'm going to be busy reading them

Bye for now

N

 

[redhunter350]

Hi Barry, I have a pretty much identical machine purchased new around 1977, mine has the power cross feed as well. Regarding the bed casting I am sure they are considerably beefed up on the long bed, the casting is deeper thus keeping the stiffness and rigidity of a standard bed.
One thing I would consider if you decide to cut the lead screw and reverse it I have often thought it would be good to have a shear pin built into the feed and it could be incorporated in how ever you decide to re-join the two parts. I also have an Emco super 11 and this has a shear pin made from soft aluminium in the lead screw to prevent damage should an error be made.
John

 

[bazmak]

Thanks Norm and John for your input. I have finished the gearbox and successfully reversed the leadscrew.Just going out to finish now and pin it
will fit a shear pin as you suggest,will be interesting.Will post shortly Regards barry

 

[bazmak]

Latest progress.I wont bore you with the general clean and paint refurb. With the gearbox the leadscrew goes right thru
and uses the 25mm thk walls as the bearings for the leadscrew ,no bushes.Cant understand why Myford.I realise there wont be much wear
but when there is there are no bushes to replace.However I digress.I cut the leadscrew so that the joint falls central bearing area of the front gearbox wall. About 12mm per side.I then reversed the leadscrew and machined the tailstock end to 12mm dia threaded m12 and bushed the brkt also 12mm
I then made and fitted housings for 12mm thrust bearings.I went up from 7/16" bsf to m12 because it was simpler.I was going to buy a new m12 nyloc nut but finished up running a tap thru the existing nut.Go figure,i then found a 7/17bsf die that I did not know I had. Or well,a non std super 7
I machined the ends of the leadscrew at the headstock end and drilled and tapped m8 ,fitting an M8 stud to screw the parts together.Made a new 19mm dia collar/spacer to conn ect together. I then pinned the joint with 2.5mm roll pins and pinned the collar to the leadscrew with a 2.5mm dia soft iron rivet.Goes together well,works well and looks good.Next job is to refurb the the broken end door backplate

 

[redhunter350]

Hi Barry looking good but I would consider alloy for the shear pin, I think steel / iron may be too strong. Better too weak in the event of an error.
I was going to add a photo of the shear pin for the Emco but failed ! guess you have to make an album on the site first ???
However it is soft alloy, I made some from alloy large rivets, only ever needed one when I ran into the bed stop while screw cutting and the Emco suppliers price was ???*** Anyway they are 5/32 dia with a head of 3/16 the head stays in the outer collar and the pin passes about two thirds + through the lead screw. The head is slightly knurled to facilitate easy insertion and removal.

One last point and please take this the right way -- I notice you did not appear to use a rear remote steady when turning your lead screw on the bench lathe -- makes me shudder ! Believe me that bar could bend at even modest speeds and the result can be devastating and cause serious injury. PLEASE use a steady I know first hand from a personal tragedy what the consequences can be.
John

 

[redhunter350]

Hopefully these are the photos ?
View media item 1438View media item 1437

 

[bazmak]

Thanks for your input John. No need for a rear steady it was very stable at low speeds and I have had plenty of experience
I remember parting off short spacers of copper tube.When it goes it goes and it went as it throws out its a quick slide to madness
all the way to 90o fortunately I was well clear and it was years ago with a larger Chinese lathe.No damage apart from the tube but it gave me quite a scare
The 3/4" leadscrew was very stable but I did keep a close eye

 

[goldstar31]

deleted

 

[bazmak]

Just spent a couple of days,improving the repair to the badly broken end door support plate
It had been repaired rather robustly with 10 n0 m6 nuts and bolts.The screw hds prevent the cover seating correctly
I assume someone had overtightened the rear fixing screw without the 6mm spacer between the cover and the headstock
The ideal way would be a new cover or alum welding but I decided to make do with what I had.Much improved looks
not perfect but most of it is hidden so will make do for now

 

[bazmak]

Bit more done,time consuming part is waiting for paint to dry so I do a few things inbetween so things might look a little mish-mash
Finished and assembled the drive from spindle to leadscrew and the main spindle with a new belt.Apart from the broken cover
everything looks goods.Just starting fitting the carriage and polishing up the ways with wet/dry. Lots of play so I replaced the 15thou shims
with 10thou and its almost there. I get everything cleaned and painted first,get it near and the fine tune the fit and paint later

 

[bazmak]

Almost finished.Just waiting for the paint to dry on the motor and then we will have first power up
I must say it was easier than I expected and much quicker than I thought.3 weeks so far and looking good
When I cut off the main drive belt it measured 800lg but is supposed to be 750mm lg so I bought at 750
and it was way too short so had to replace with 800mm long. Any comments ? Its nice to see the pile of dirty sub assy's reduce
and the finished assy get heavier. Fitted my 6" myford chuck that I kept from the ml7s then first job is to machine up a backplate to suit my
4" range of Chinese chucks.Tailstock and guard to finish off then I can finess the paint finish and slides etc

 

[DJP]

Remind me... is this keeper for your use or a restoration for sale? I have the identical lathe and I know that they are priced higher than equivalent older lathes so maybe a good business venture to rebuild and sell. Mine is still in very good condition and used for my projects so don't get any ideas. It's not available.

Nice restoration and the blue colour suits the machine better than gray.

 

[bazmak]

Im a retired engineer and do it more for fun rather than the money.Obviously a very low hourly rate
I did 3 no ML7s and made enough to buy this at a good price so what you see is a freeby.Havent made
up my mind what to do with it.I did want a super 7b but not the long bed so will wait and see.If something else suitable becomes available
I might buy another and sell this. Love Myfords.Had a near mint ML7R in the UK as pictured and like a fool sold it