Mark VII Headstock Lock & Crank

[JPG]

The Mark VII headstock lock is activated by the same handle/crank as the headstock positioning. When the knob faces out, rotating the crank moves the headstock along the way tubes. When the knob is flipped over and pushed in, the headstock lock wedges clamp the headstock to the way tubes.

Since the shaft has a compressed spring, the first stop is to remove the nut on the end of the shaft.

[ATTACH]19519[/ATTACH]

The nut is a 'castle' nut that can be adjusted for wedge wear, but does not require a jam nut. A washer is under the nut.

[ATTACH]19520[/ATTACH]

This bracket retains the worm gear. The worm gear rotating rotates a counter shaft that has a spur gear that engages a gear rack on the front way tube.

[ATTACH]19521[/ATTACH]

The worm gear is keyed to the headstock lock shaft by a woodruff key.

[ATTACH]19522[/ATTACH]

All the parts in order.

[ATTACH]19523[/ATTACH]

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Now a puzzle. How to get to the pivot of the knob to the shaft.

[ATTACH]19524[/ATTACH]

This has a small ding that was preventing it being removed from the shaft.

[ATTACH]19525[/ATTACH]

The pivot is a tension pin that is driven out.

[ATTACH]19526[/ATTACH]

Apart at last.

[ATTACH]19527[/ATTACH]

Last three screws remove the shaft cover.

[ATTACH]19528[/ATTACH]

This thread is linked to from https://forum.shopsmith.com/viewtopic.php?t=11373&highlight=journey