myford super 7 clutch

hi chaps, is it possable to repair a myford super 7 clutch, i have the myford book which is a bit none on the subject. michael

Terry Whats wrong with it ?

Roy

What is wrong with it?

Mike

hi, sorry should of said. the clutch will not disengage the gears, to stop the work i need to stop the motor, which i understand is not a good thing for single phase motors. I got the lathe this way, but would like to get the clutch working as it should. michael

If it has never worked I think you will need to dismantle it to check the ball bearing and push bar are fitted. If you have a manual there is a sectional view of the clutch and setup procedure, together with the exploded parts diagram you should be able to see how it works with a bit of study.

Mike

It may be that the cones have just got stuck together through lack of use.

Take it apart and give it a good clean, it probably wont have much wrong with it.

Phil

First question is are you a Terry or a Michael?

Next question is does the clutch operating lever flop about, or is it stuck fast in some position?

There are two S7 clutches. Early answers assume you have the later (post 1956) version, so what is the serial number of your machine?

On no account at this stage release the central nut on the end of the modern cone clutch (as implied by early answers). You could have a push-rod fly across the room, and you will not be able to get it all back together without a fancy (special) spring compresser.

Dennis

Hi Dennis

".....are you a Terry or a Michael"

Sorry - I'm lost.

Good advice on the later clutch though.

Norman

Edited By NJH on 20/01/2013 17:51:25

hi, Its Michael, I have had a look for the number but its hard to see at the rear of the lathe. what I can make out is 71/1104/3 well that is what it looks like to me. On taking a bit more of a look at the clutch action, there is not an any way that I can see to adjust the clutch. the actuating rod moves and forces the end section of the clutch around 1/8th from the pulley. But it does not slow or stop the gearbox action.I only have the myford book by Ian Bradley which is not help in this area. michael

Michael

I have sent you a PM

(Sign in, Go to the box at top left " My Account" and click on " My Messages" to locate your In box.)

regards

Norman

So "hi, Its Michael, ". Strange psuedonym then, but never mind. Perhaps it's Terry's machine.

Seems like NJH is sorting you out away from the crowds. No bad thing as it seems you need a Myford manual copy and some personal help. There is some good news. With the serial number on the back, it should mean your bed has never been reground should it need it, and would come up like new in the right regrinding hands, if you can find any outfit to do it.

Your serial number is in a form SK123456, always SK if the bed started life as a Super 7 one, and up to six numbers. 71/ might be the SK, but you cannot have number 110413 as such a high number was never on the back of the bed. Even if it is as low as11043 it is the modern clutch.

However, I now realise that you are talking about gears and gearboxes not being stopped by the clutch. Does the mandrel stop with clutch action? If it does then there is nothing wrong with the clutch, but NJH seems to be onto your problem. My main concern in getting involved was you releasing that nut as previous mail and doing someone a mischief.

Dennis

there is a chap in leeds now regrinding myfords

Thanks chaps for all your input, at the moment it looks like a seized bearing in the drive pulley. As to my name its terrance michael, But I have always been called michael.

Hi Dennis

> On no account at this stage release the central nut on the end of the modern cone clutch (as implied by early answers). You could have a push-rod fly across the room, and you will not be able to get it all back together without a fancy (special) spring compresser.

Could you go in to more detail on this please? My S7B has a problem with the cone clutch - running out of adjustment at the outer nut/slotted end of pushrod, noisy operation - and from examination of the parts catalogue and the manual I have suspected that what you describe would indeed happen, and clutch bits would disappear to remote corners of the workshop if I attempted to dismantle it.

Yours sounds like the voice of bitter experience! Any practical advice on dismantling this box of tricks, please? Can you describe the spring compressor?

Thanks
John

Edited By jwb on 21/01/2013 10:36:16

Hi Michael , I have the Ian Bradley manuel and on page32 there are instuctions on how to adjust the clutch

book is ISBN 0-85242-775-1 hope this helps Maurice.

Hi Chaps, after playing around a bit more, and pulling this and that. I found that the clutch drive was stuck in the drive pulley so giving drive all the time. With a few taps on the pulley using a wood dolley, the clutch came free. after washing the pulley with carb cleaning It all works ok. I will now spend the rest of the day with the oil can. thank you for your help. michael

Hi John, and others, I put new bearings in my coutershaft last week and (in my blissful ignorance) didn't realise it could be difficult. I stopped things flying by leaving the end cover on when pulling the lever out. I put it back together by pushing the rod through, putting the plate on backwards and tigthening as far as possible, wedging a rod down the lever hole, putting the plate on again with a spacer until the lever went in, reversed the plate and adjusted. So no need for special (and expensive) puller. Hope this helps.

BTW, someone said they have ran out of adjustment, could the ball bearing be missing? Eddy.

For jwb, Michael C, and anyone else with S7 clutch problems

Quote from jwb:

"Could you go in to more detail on this please? My S7B has a problem with the cone clutch - running out of adjustment at the outer nut/slotted end of pushrod, noisy operation - and from examination of the parts catalogue and the manual I have suspected that what you describe would indeed happen, and clutch bits would disappear to remote corners of the workshop if I attempted to dismantle it.
Yours sounds like the voice of bitter experience! Any practical advice on dismantling this box of tricks, please? Can you describe the spring compressor?"

Sorry jwb, but I but I do not live on the internet. I only log on every couple of days or so.

You both need the two bearings at the right hand end of the countershaft. I can only assume that Eddy Spriggs method above works. I was lucky to get mine done as part of a bed regrind by Myford just before they went down (very sad).
The problem is the spring inside the countershaft. Uncompressed, it is about twice as long and very strong. Any compression device for it would need to be 500-600mm long minimum having a long and powerful compressing action, long enough to get the nuts on the end into the right position, which is with some thread of the pushrod sticking out beyond the locknut. It would also need a big bow to fit over the pulley/clutch end

The push rod can be adjusted as in Ian Bradleys book with a screwdriver in the slot at the end of the pushrod and the nut released, but this must only be considered as a fine adjustment aide. The push rod should never be rotated against its spring any more than can be helped as the action will create swarf inside the assembly by the ends of the spring rubbing on the countershaft shoulder (at the left end ) and the pushrod head (at the right end). It really is that compressed - it does have to prevent the clutch slipping remember. It follows that it is not on to get the pushrod just started (not that I can see anyone would manage it by hand anyway) and wind the rod in the rest of the way. If you try any adjustment before attempting disassembly, you will understand.

Sorry I cannot be more help. There really is no practical advice as it depends on your facilities. Not that it helps, but Myford replaced the bearings in minutes. It sounds to me like jwb may win with Eddy's method, but the clutch should not "run out of adjustment" unless there has been clutch slip wearing out the cone. If you have noise, then you have bearing trouble, but you may need other parts as well. Michael will need a total stripdown anyway as the bearings are sealed-for-life type and he has introduced all sorts of foreign bodies in his "cleanout" where he cannot get, round the spring and pushrod area, and his clutch action will never be smooth or noise free.

Good luck to you both, and to anyone tempted to release that pushrod without restraint. Such action would be very dangerous to skin and bone!.

Dennis

Eddy

Thank you for the useful advice - I see how you did the job. Cunning!

The ball is not missing since the clutch hasn't been disturbed from new, but something has been wearing at the operating handle end judging by the gunge which has appeared over the years. I suspect the operating lever cam surface or the end of the 'push bar' (Part 9 in Fig 37 of the manual; Part 117 on the 'Motorising Assembly' catalogue page).

Thanks again. I'll look at it closely this weekend. It's a job which clearly has to be done with great care.


Dennis/DMR

Thank you for your very detailed reply, full of useful information. As mentioned in my above reply to Eddy, I strongly suspect wear at the right-hand end. I am pretty sure the cones are fine; they've always been properly lubricated and there is no sign of wear. The noise is a death rattle which is definitely not bearing noise but is due I think to the cam action of the operating lever and the wear which is in there somewhere.

Your advice about the strength of the spring is a useful warning - this is what I suspected - it's a very strong spring.


Thanks to both
Regards
John

Any help in how to unfreeze the clutch plate please? I too am in the process of disassembling the Mk2 S7 clutch and cannot seem to progress with the clutch plate on account of not being able to move the pushrod. I have read the warnings in this thread about flying pushrods and would like to know why mine is not flying off yet as I have removed the countershaft from the lathe, with pushrod, spring, cone all connected, and the 1/4" hexagonal nut removed. I presume the push rod is actually held captive by the Driver Plate (the disc secured with 2 allan cap screws) which would mean that this driver plate is threaded - is this the case? Is this what DMR means by "the central nut on the end of the modern cone clutch"?  Turning the split end of the push rod results in no movement and just destruction of the split parts of the end! Attempts at turning the Driver Plate results in no movement either. Everything solid. Currently I have the shaft sitting vertically in the vice with the open cavity end uppermost and filled with WD40. Any advice on my next move move most keenly appreciated. Thank you.Adam

Edited By Adam Harris on 13/04/2014 21:49:46

Edited By Adam Harris on 13/04/2014 21:53:41