geebee509 wrote:

Do you coat the part with Prussian Blue? How, a finger tip, what
thickness?

You coat the plate with touching blue (I think you call it that way).
About a fingertip on wipe that you spread over the plate (area where you
want to touch).
The thicker the blue is, the less precise results you get. Imagine
having a layer of 1mm on the plate.*) :-))


How do you test it on the surface plate - press it down gently, slide
it, rotate it, what?

Gently lay the part on the plate. Move part with little circular or
longitudinal (depending on shape of part) gentle movements. Try not to
tilt the part or you will get false results. If the part tilts/rocks,
you might get it roughly in shape using a straight edge before
proceeding with the plate.
Touching surfaces _can_ get very tricky!


How would you prepare the surface plate - clean with alcohol, use a
damp kem wipe, what?

There are special cleaning agents. I use petroleum.


Do you test flatness on different sections of the surface plate?

Not on mine, I know that it is flat everywhere. :-)

*)
I have seen that in a report about a famous airplane manufacturer when
they fitted wings to the body. I won't tell names to protect our
European industry. ;-)


HTH,
Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO // Eigenbau-Digitalanzeige
http://www.yadro.de