But you see that you really need to use a controlled temperature water bath to get the best out of your Jo Blocks.
Well, surprise, surprise but tou do.
It's a bit like checking viscosities using a a PRS Viscometer or a perhaps Number 4 Ford cup.
Again, I DO know Statistical Quality Control. Never mind the why's and wherefores but it is not far renoved from the maths in Cost Accountancy
But in most cases, a set of Jo Blocks is overkill and something simpler and you can't have somebody with a set to jumble and spill so something could be desirable.
A set of homemade 'blocks' i say 1/16th or a set in millimetre intervals often suffices!. I have cheap and far from nasty set of professionally made metric ones!
Sometimes a 6" Ruler 'stuck' to a square block can be used to set up work- Quickly.
Again, I made up a set of spring loaded indicators for setting up stuff in a 4 jaw independent chuck.
Of course-- ho ho ho, I use a centre pop and - that's it.
And of course, I have rather wonderful DRO system on the Myford and a cheap and actually quite nasty so called DRO
Oh and perhaps, I have drifted off but I have--- shush-- stub drills
N