Stuck set screw...

Ststephen7

Ststephen7

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Ok... Dave and I got my new Sheldon into the basement, and I am reassembling it. It has a U drive...

I got the motor and U drive mechanism up into the cabinet (by myself I might add), put the belts back on, and wanted to make sure the handles fit the posts... I got a bit of paint in the holes...

Anyway... I shifted the speeds, while turning the pulleys slowly, and I have a problem. The right shift lever is not firmly connect to the mechanism on the end of it (that shifts speeds)... The lever moves about 180 degrees before engaging the mechanism.

There is a collar, with a set screw, and I believe that collar should fix the lever to the mechanism.

However... the set screw is stuck in there... won't move in or out. AND... hand to God... it was boogered up when I got there! My allen key was a sloppy fit the first time I put it in, and it just spun around in the set screw recess with a minimum of effort. The next size up will not fit, even with a little help, nor will any close metric key.

I REALLY don't want to remove this whole motor drive unit AGAIN... Yet I have very little access to this set screw.

Even with the drive unit out I won't have direct access, without at least partially taking apart the drive unit, which I don't really want to do...

Any ideas of how to remove this set screw without removing the U drive? How about with removing the drive? I don't have any left hand drill bits...
Thank you!!!

Steve

This first picture should show kind of where the set screw is... behind the painted part, just before the cast mechanism, on a collar... The next pictures show how far I need to move the handle before it engages... not acceptable. You can see the casting has moved, from the second picture to the third... it should be about a 45/60 degree throw...

and I imagine the overwhelming answer will be remove the motor and drive, and then something, something, something... crap!

This is the set screw.png
IMG_3282.JPGIMG_3284.JPG
 
Irwin sells full sets of easy outs that will remove that set screw in 10 seconds . I use them everyday pulling screws from extrusion dies at work . They are not the long left hand spirals used with tap wrenches . These are short and used with sockets . Shoot it with Kroil 5 minutes before removing .
 
The spirals are prone to breakage but they have the advantage of extra depth . I've only snapped one Irwin over the years and that was with a IR 1/2" air impact driver . Money well spent when you need them .
 
Sometimes a bit of dirt in the hex socket of the screw will prevent the bit from bottoming in the screw. It does not take much dirt to reduce the engagement of the tool. You have probably already cleaned out the socket thoroughly but because of its location I suggest that you give it another cleaning with a sharp hard pick and compressed air.
Try to get a good look at the clean screw with a mirror and light. The socket maybe too far gone to have any chance of holding a bit.
Is there room to drill and tap a new hole for a second set screw so that the oem one can be ignored?

PS Did not see the above posts, too slow typing, sorry about that. Glad you got it.
 
There is possibly a groove worn into the shaft by the loose set screw. Will a new set screw bite properly into the shaft to prevent it slipping again like before?
 
It's quite possible the set screw loosened slightly over time. Just enough to allow it to create a groove in the shaft. If there's enough material in the sleeve I would suggest using a short cup point set screw with blue Loctite (242) to help hold it in place. Then put a second brass tipped set screw in the hole and tighten it against the first. If there isn't enough room for 2 set screws I would use one longer than the hole is deep and put a lock nut on the part extending out of the hole.
 
Glad to read you got the set screw out and without needing to remove the mechanism. Good job getting all that back in place by yourself. Nice work cleaning up the lathe. Looks so much better than the black dirt and debris over everything.
 
Blue loctite still means heating to loosen the set screw down in a hole. Why not use a longer square head set screw and maybe a nut for locking the two together. A longer square headed set screw could be heated easier than a recessed allen socket set screw. A second set screw would require a disassembly. If you can move the collar back, can you dremmel off a flat spot to keep the collar from moving? A flat spot solves several of your problems. My 2 cents
DBQ49er
 
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