Misc details about Mark V headstock

[ALarryAaron]

These are questions that have perplexed me for a while, so now I'm getting around to asking you Shopsmith experts:

1. There are 2 small prongs on the external face of the quadrant assembly. Is the purpose of these to give a resting place for the head of the dial spring or are they for something else?
2. On the back of the speed control dial (part #5042259) there is a v-groove that goes about ¾ of the way around the dial. What does this groove do? I don’t see any part of the machine that engages with this groove, yet it looks like it performs a range-limiting function.
3. There is a 3-prongged asymmetrical-shaped cut-out on the front of the headstock (where the quadrant arm is inserted into the machine) that supports the back of the installed speed dial/control arm assembly.
a. Why is it shaped that way?
b. Is there a functional reason why this is 3 pronged rather than a round cutout?

[br549]

I can't fully answer all of your questions, but this thread should shed some light on Question #2.

viewtopic.php?f=6&t=7095&p=274300&hilit ... al#p274300

[JPG]

1) THEY RESTRICT THE MOVEMENT OF THE SPRING LATERALLY.

2) THE ANTI-RATTLE SPRING RIDES IN THAT GROOVE. AT SPEEDS ABOVE SAW JOINT THE GROOVE ENDS AT A RAMP. THE INCREASED TORQUE REQUIRED TO ADVANCE THE DIAL FURTHER TOWARDS FAST PROVIDES TACTILE FEEDBACK(SORTA). "A" HEADSTOCKS HAD A STEP AT THE RAMP LOCATION. THE OPERATOR NEEDED TO PUSH A BUTTON OUT OF THE GROOVE TO INCREASE SPEED BEYOND THAT POINT.

3) THAT HOLE SHAPE HAS VARIED BETWEEN THE DIFFERENT HEADSTOCK VERSIONS. THE THREADED HOLES NEED TO BE THERE TO SECURE THE SPEED CONTROL AND THE HOLE NEEDS TO BE THERE TO INSERT THE SPEED CONTROL THROUGH. OTHER THAN THAT THE SHAPE IS ARBITRARY, BUT EASY ASSEMBLY AT THE FACTORY IS A FACTOR.

[ALarryAaron]

You are so knowledgeable and helpful, JPG.

Thanks a lot for the energy and time time that you and the other contributors put into this site.

It's a real gift to us ordinary users.