Tuesday, July 23, 2019

A Mastercraft Work Stand's Vise Screw Lash


I have an elderly Canadian Tire Mastercraft work stand that has a couple of vise screw peculiarities.


The screws' actions are counter-intuitive -- it's clockwise to loosen; counterclockwise to tighten. There's not a thing that I can do about that; it's the nature of the beast. The manufacturer no doubt didn't want to incur the additional cost of left-handed screw threads. Left-handed screw threads would impart intuitive vising action to the work stand's jaws; i.e. clockwise to tighten, counterclockwise to loosen.

There is a peculiarity that I can do something about, though, and that's the outrageous amount of lash[1] in the vise screws. Note the gap between the crank and the frame in the following photo.


That gap lends about a couple of turns of play to the crank's action. The crank on the other side is the same. It's annoying. If I can install a couple of flat washers to take up that space, I should have a work stand that's much more pleasant to use.

Knocking out a roll pin freed the crank from its screw. A pair of 3/8" SAE flat washers fit nicely for play eliminators.


And here we are with the crank reinstalled.


I lubricated all the thrust bearing points and the screw with roller chain lubricant, and now I've got vise screw action with no binding, and minimal lash. Much better.

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Note:

[1] See this 'lexicon' post for an explanation of my use of the term 'lash'.

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