Myford Super 7 clutch adjusting screw over tightened

[Francis DuguidParticipant @francisduguid24161]

1955 Myford Super 7, serial No. SK4096

[Francis DuguidParticipant @francisduguid24161]

Dear All,

In my haste to adjust a slipping countershaft clutch I wound on the adjusting allen grub screw with the clutch in the "in" position, i.e. the disengage setting, refitted the blanking plug, then switched it on to commence cutting.

The clutch is now permanently engaged, the lever effectively fixed in the disengage position and worst of all the blanking screw hole no longer aligns with that for the allen screw to permit a back out.

Suggestions please as to how I rotate the the belt pulley with respect to the shaft to align both and permit access to that allen screw.

Any help greatly appreciated, thanks.

[egaParticipant @ega]

Is this the early clutch or the later one?

I didn't really follow your explanation of the problem but at least this will bump your post.

I have the manual covering the later clutch and could post an extract if this would help.

[Simon Williams 3Participant @simonwilliams3]

Welcome to the forum!

From the description and the date, this is the old style horseshoe shaped clutch made out of cast iron, located inside the top multi step pulley under the drive cover.

Unfortunately I rather think you've boxed yourself into a corner with this one. Best I can come up with is to observe that the clutch has slipped under the start-up load, otherwise the adjusting screw hole would still be lined up below the screwed bung hole. If I've interpreted this correctly it means that the clutch is not rock solid.

Let's see if we can reverse the symptoms and recover the original situation by slackening the belts taking the drive down to the spindle, then grab hold of the countershaft motor pulley and the multistep pulley and see if brute force will prevail. I'd try turning the multistep pulley backwards to see if the clutch will allow a little bit of movement.

Bit crude, but it's the best I can offer so far.

I've been trying to import a pdf from the service manual with an exploded view of the offending bits, but I haven't succeeded.

HTH Simon

[noel shelleyParticipant @noelshelley55608]

Sounds like an early version and the pin has gone over centre ! may need dismantling to reset. Noel.

[Simon Williams 3Participant @simonwilliams3]

Pictures as from the relevant bit of the user manual here

[Francis DuguidParticipant @francisduguid24161]

Dear All,

Many thanks for the replies. I suspect it's an early clutch and yes, I did try the "brute force" option but unfortunately no slippage atween the countershaft and cone pulley, perhaps insufficient brutality !

My only option is to remove the complete swing head carrier and try to dismantle the countershaft / cone pulley assembly in the hope that my actions have not virtually locked the cone / clutch to the shaft. Or I could leave as is and risk the early demise if the single phase motor with more frequent stop / start cycles.

When I bought the lathe in 2005 I'd reason to call Myford at Nottingham and spoke with David Auchell who advised on set up after a transcontinental move and sent me copies of Accessories & Ancillary Equipment for Series 10, 7 and 254 Lathes, Super 7 User Manual and similar for the Quick Change Gearbox. In fact from the serial number he confirmed the delivery date and address to first owner from whom I bought it from.

[KWILParticipant @kwil]

Francis,

There is a David Anchel trading as Quillstar who deals in Myford etc machines. Is this the same David?l

[Simon Williams 3Participant @simonwilliams3]

If it is any consolation I doubt that you would ruin a single phase motor on stop/start cycling in any normal lifetime. You might blow the upstream fuse if you really went hammer and tongs at it, but the motor itself is pretty solid. The clutch is there for controllability and ease of use, particularly threading. I have a lathe of a similar vintage to yours wherein the clutch is either solid or loose, and the lever doesn't allow you to choose between them. I use it with the clutch intentionally defeated (jammed tight). It's been like that for 40 years plus, and while it is true I have fairly recently changed the motor for a three phase one it wasn't because the single phase motor was protesting. I changed it for an experiment just to see if the lathe was better with a VSD and soft start – and concluded it is much improved.

I rather think that taking the countershaft to bits isn't going to reveal anything you can't do already, as the countershaft pulley will still have the clutch horseshoe jammed tight inside it, and you won't be able to dismantle the operating linkage without resolving this somehow.

Might just conceivably be worth popping the whole countershaft in the freezer? Then heating the outer cone multi-pulley quickly? If you can get the clutch shoe to let go just enough to line up the adjusting screw I think that's your only chance.

It would be a shame to take it part way to pieces then get stuck, and not be able to reassemble the countershaft again. You're better off as you are!

Good luck,

Rgds Simon

[peak4Participant @peak4]

I can't help with your problem I'm afraid, but can confirm that it looks like you have the earlier clutch, which might guide others into assisting you.
From the Myford S7 build spreadsheet I have;

SK 8128 1958 JUNE NEW CONE TYPE CUTCH, MODIFIED MOTOR AND BELT GUARDS

Good luck and welcome
Bill

[mark costello 1Participant @markcostello1]

If it messed up by going in a forward direction, could You "bump" it in reverse to move it back a little?

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