Vernier caliper ?

[doctor Bob]

I work mostly in wood - though generally exotics - and always work to 0.01mm (drawings done to 0.0001) a digital vernier is only used for 'roughing' cuts, the final measurements generally being taken with a micrometer.

I do accept that I am an exception rather than a rule though :wink:

impressive, why the need for drawings to be 1/10000th of a mm for wood?

 

[MikeG.]

It's a bizarre claim in a number of ways. CAD drawings aren't accurate to X decimal places, they are absolutely accurate. If I measure the length of any line I've drawn and find that there is a decimal in the length, then I know I have got something wrong somewhere. There's no plus-or-minus tolerance unless you decide there needs to be for some reason, and I have never used that facility.

 

[Lons]

It's a bizarre claim in a number of ways. CAD drawings aren't accurate to X decimal places, they are absolutely accurate. If I measure the length of any line I've drawn and find that there is a decimal in the length, then I know I have got something wrong somewhere. There's no plus-or-minus tolerance unless you decide there needs to be for some reason, and I have never used that facility.

+1
Mike beat me to it.
It's quite a few years since I taught the use of Autocad to students so I've forgotten most of it but not everything.

 

[Trevanion]

I think he may of just been taking the pish fellas :lol:

 

[Max Power]

That was my understanding as well Trevanion

 

[J-G]

Apologies for my apparent dis-interest - been busy with other matters - not to mention F1 !! -- NO, I was certainly not taking the pish. (or any other euphemism you may choose)

If you don't at least strive for perfection you'll always fall short. I still fall short 99.9% of the time of course.

Taking a reading with a Micrometer should always be done using the 'Click' clutch mechanism so any 'squish' will always be the same. I've not come across a vernier with this facility.

I didn't intend to indicate that I physically 'draw' to 4 figures - - I don't take 'measurements' from my drawings, I always calculate the figures and mark drawings up to at least 4 decimal places. Calculations are usually done to many more. Oh yes -- I don't use AutoCAD or any other 'CAD' software either.

As an apprentice Toolmaker I was expected to draw 50x shadowgraph outlines of involute splines where the tolerance on a radius of 8' or more was 0.002" (Matrix were not fully metric in 1958) - this was drawn on metalic laminated card which was used in temperature & humidity controlled conditions.

For the doubters, here is a screen grab of a current project:

 

[Blister]

My new calipers arrived , The i Gaging one from Peter Sefton.

Looks like a quality unit
Thanks for the recommendation