Myford super7

[sparky mikeParticipant @sparkymike]

I just got my early Myford super 7 out of long term storage and have been checking it over. I am finding that the lever that slackens the belt for speed changing is jumping out on its own and the chuck then loses its drive. This lever works on an over centre principle. Now is that adjustable to give more lock ? Bear in mind this is an early model with the different clutch system than the later models.

Mike.

[noel shelleyParticipant @noelshelley55608]

Sounds like you have the Raleigh brake shoe clutch. Take a look at an exploded diagram and how to adjust it becomes obvious, I seem to think it involves a grub screw. I will get the book out and refresh my memory. Noel.

[brickyParticipant @bricky]

Beware of the grub screw in the clutch as there is another underneath of it.If it is a pree 1959 model.

Frank

 

[Grindstone CowboyParticipant @grindstonecowboy]

If it’s the early model, the clutch is the horseshoe shaped cast iron one. But it sounds like it’s the belt tensioning lever that the OP is talking about, not the clutch (he just mentioned that to stress the age of the machine?)

If it is clutch adjustment you want, I have some pictures I can post – I think I got them off this forum originally.

Rob

[Grindstone CowboyParticipant @grindstonecowboy]

I’ll post them anyway, they probably got lost when we switched to the new forum software.

Rob

[ChrisLHParticipant @chrislh]

There are a couple of long grubscrews with locknuts atttached to the bases of the countershaft bearing pedestals. The out of sight ends of the grubscrews bear on flats on the shaft attached to the belt slackening lever shaft. You may improve things by adjusting these grubscrews but more likely the corner between flat and shaft diameter has worn to a large radius destroying the over centre effect. Looking at my identical model S7 it looks as if the lever is somehow cast intergrally with its shaft, no sign of locking screws, etc. So I guess it’s either

buy a new lever/shaft assembly or

file the lever shaft flats deeper to get a sharp corner and adjust the grub screws to compensate or

file away part of the stop on the lever which bears on the end of the shaft behind the lever shaft to go further over centre (or file a flat on this shaft) or

a combination of any of the above !

Good luck. Feel free to PM me if it doesn’t make sense.

[Charles LamontParticipant @charleslamont71117]

I have seen Super-7’s in workplaces where there seems to be a tendency to turn the belt tensioner lever the wrong way. It is anticlock to release and clockwise to tension, ie push the lever back, not down.

[sparky mikeParticipant @sparkymike]

As far as  know, nothing to do with the clutch. That is working fine. It is just the lever which slackens the belt, jumping out of run position.

Mike.

[ChrisLHParticipant @chrislh]

Mike,

I, for one, was not referring to the clutch. My response deals with the problem as stated in your original post.

[noel shelleyParticipant @noelshelley55608]

My guess is that the 2 small flats on the belt tensioning shaft have worn round and with luck filing them to a face will restore the function, with some adjustment to the 2 bolts/ grubsrews that bear on the flats. Good luck. Noel.

[noel shelleyParticipant @noelshelley55608]

Further to the above ! I went to the shed and had a look, there are 2 slot headed grubscrews with lock nuts. Mine slipped out of gear this afternoon for the same reason, or may be was not properly in gear to start with. Noel.

[Charles LamontParticipant @charleslamont71117]

They should not be grubscrews. The tension adjusting screws have specially profiled heads to bear on the camshaft. I think they may be hardened too.

[noel shelleyParticipant @noelshelley55608]

Hi Charles, My machine an S7 of 1969 and is unaltered from the factory . My description is as I see it and though technically may be not correct is the best way I could put it to someone who doesn’t know the machine as well as you do. I hope the information will help the fellow solve his problem. Noel.

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