A mate of mine is having problems with the clutch on his Myford Super 7, in that although declutched, the chuck continues to revolve slowly.
I have suggested that there must be some dust trapped between the brass friction plate and the drive pulley.
We decided to dismantle and have a look, but how does one separate the brass plate end from the rest of the assembly, when it appears to be held in by a spring under tension?
(We have the spindle with the brass plate and drive pulley removed onto the bench)
Unless absolutely necessary, we are loth to remove the circlip holding the bearing in place, for fear of needing special tooling to put it all back together.
It may not be the approved method (what is the approved method I wonder?), but I have successfully taken my clutch apart recently.
The key point is that the internal spring needs to be compressed so that th e drive plate on the end of the operating spindle can be safely removed. I imagine the factory method uses a jig to compress the spring, but my method relies on using normal clutch operation (i.e. the the countershaft needs t o be installed in the lathe). Remove the two screws which retain the smal l central drive plate. Remove the lock nut on the central adjuster. Diseng age the clutch (i.e. so that the drive plate is lifted away from the bronze plate). Rotate the central spindle with a screwdriver until the dogs of th e drive plate are fully clear of the bronze outer disc. At this stage you can unscrew the drive plate by hand and remove it. The bronze plate should now just pull off. It may be tight if the slots in the end of the counter shaft have become burred or spread (mine was like this). If you want to rem ove the drive pulley as well, it is only retained by a circlip.
Reverse procedute to reassemble. Make sure the slots in the countershaft a re aligned with the dogs on the central drive plate, or you will jam up.
It worked for me, but proceed at your own risk!
As an aside, I took my clutch apart because it was dragging. This was caus ed by a combination of the bronze plate being sticky on the countershaft, g eneral gunge, and by the drive pulley moving with the bronze plate when the clutch was operated. This movement was due to the circlip which retains i t being deformed (my lathe is 50 plus years old). A clean up and a new cir clip fixed the problem.
The key point is that the internal spring needs to be compressed so that the drive plate on the end of the operating spindle can be safely removed. I imagine the factory method uses a jig to compress the spring, but my method relies on using normal clutch operation (i.e. the the countershaft needs to be installed in the lathe). Remove the two screws which retain the small central drive plate. Remove the lock nut on the central adjuster. Disengage the clutch (i.e. so that the drive plate is lifted away from the bronze plate). Rotate the central spindle with a screwdriver until the dogs of the drive plate are fully clear of the bronze outer disc. At this stage you can unscrew the drive plate by hand and remove it. The bronze plate should now just pull off. It may be tight if the slots in the end of the countershaft have become burred or spread (mine was like this). If you want to remove the drive pulley as well, it is only retained by a circlip.
Reverse procedute to reassemble. Make sure the slots in the countershaft are aligned with the dogs on the central drive plate, or you will jam up.
It worked for me, but proceed at your own risk!
As an aside, I took my clutch apart because it was dragging. This was caused by a combination of the bronze plate being sticky on the countershaft, general gunge, and by the drive pulley moving with the bronze plate when the clutch was operated. This movement was due to the circlip which retains it being deformed (my lathe is 50 plus years old). A clean up and a new circlip fixed the problem.
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