Re: [CAD_CAM_EDM_DRO] Which to trust, home-built DROs or hash marks?

Peter L. Peres wrote:

>I think that I can add a small verse that may answer your question:
>
>When you go out to sea
>take one clock or three.
>
>This is an old english sailor's saying afaik. And it is true. Had you had
>one dial to read you would have trusted it. Having two different ones, you
>are confused, having three different ones is even worse.
>
>The right thing to do would be to obtain a caliper caliber (I do not know
>what it's called in your parts). Usually it's a cube of metal machined
>very accurately to 1x1x1 inches or similar, that comes in a small padded
>box. That would allow you to check your calipers. It may be shaped as a
>square ruler or triangular section ruler or cube. I do not know where to
>get one now but these must exist. They used to just be there in machine
>shops. Probably NIST can tell you where to get one in your country.
>
>

Micrometer standards generally come with all micrometers over 1" (25mm).
Or, you can use gauge blocks to check calipers at a variety of distances.

A stack of gauge blocks can be used to check the errors in leadscrews at
periodic distances, to build a calibration table.


Jon