Mark VII Mystery clip

JPG · Post by **JPG** » Sat Feb 23, 2013 11:30 pm

While reassembling the headstock on my Mark VII I discovered(from the parts manual) that a wire clip is missing. It is #39 below.
[ATTACH]20320[/ATTACH]

What does it do?
What size wire is it?
I assume it goes into a through hole in the shaft.

benush26 · Post by **benush26** » Sun Feb 24, 2013 2:51 am

I have no clue as to size (wire gauge thickness)

However, if I was to hazard a guess as to its purpose, it would be to keep the handle from flopping around. So either the handle is up in the folded position or down to be used for adjustment.

But then I've been known to be wrong on days that end in "Y". And the older I get the more days that becomes.

JPG · Post by **JPG** » Sun Feb 24, 2013 10:16 am

benush26 wrote:I have no clue as to size (wire gauge thickness)

However, if I was to hazard a guess as to its purpose, it would be to keep the handle from flopping around. So either the handle is up in the folded position or down to be used for adjustment.

But then I've been known to be wrong on days that end in "Y". And the older I get the more days that becomes.

Reasonable guess, but, The crank is under constant tension from another spring and is not free to 'flop'.

The 'crank shaft' serves two purposes. The obvious one is to position the headstock, and the second is to lock it in place. The knob etc. must be pushed in to release the headstock lock. The lock works similar to the 505-520 carriage lock except the lever is pushed rather than rotated. Pushing the knob/lever pulls the rear wedge away from the rear tube thus relieving pressure on the front wedge and tube. When released a spring causes the wedges to squeeze the tubes. That spring also exerts pressure against the crank. The knob/lever serves as a stop for the front end of the shaft and a locking nut adjusts the tension on the rear end.

The shape of the spring(from the parts manual drawing) appears to match a profile on the crank handle and may indeed serve as a latch spring that would help prevent inadvertent re-locking of the wedges while cranking. As it is(sans spring) the knob must also be pushed while 'cranking'.

fjimp · Post by **fjimp** » Sun Feb 24, 2013 12:17 pm

Prior to being banned from the workshop. One of my last projects was adding wheels to the workbench. When finished I was thrilled until I performed the required push test. At this point I discovered a number of missing parts, screws, springs and items I have no idea where came from or what they resemble. Have you checked under the bench? Jim

Sorry I couldn't resist. Actually I know better you are far too organized to lose anything.

JPG · Post by **JPG** » Mon Feb 25, 2013 12:19 am

fjimp wrote:Prior to being banned from the workshop. One of my last projects was adding wheels to the workbench. When finished I was thrilled until I performed the required push test. At this point I discovered a number of missing parts, screws, springs and items I have no idea where came from or what they resemble. Have you checked under the bench? Jim

Sorry I couldn't resist. Actually I know better you are far too organized to lose anything.

Ain't so!:(

When I put the last retaining ring on the cross shaft(headstock positioning gears) it slipped off and went to I do not know where! Hope I can find one that will 'work'.