Bruce C. wrote:
Couple of ideas from outside the box:
1. Put a GPS reciever in the anvil and another one in the screw. Feed the
signals to a PC to compute the diference.

Uh, not the easiest approach. Although you could do differential
decoding to find the distance between the two points accurately despite
GPS not giving you *absolute* positions very accurately, it still
wouldn't be *very* accurate, and it'd be bloody complex!

2. Use an ultrasonic transducer coupled to something like a Time Domain
Reflectometer (TDR). Now you can read the thickness without having access to
the other side. Or maybe you can read the thickness of an anodize treatment.

Might be interesting to develop a micro-radar or micro-sonar where the
sensor head transmits pulses and then you use an oscilloscope to view
the reflected signal as it comes in - the further down it's looking the
longer the echo took so the further along the scale the point has moved.
Once it was calibrated, you could put it on a surface and see things
like the actual far surface, but also things like the layer of solder
within a braze joint, etc.

I also like the "talking micrometer" already mentioned. How about a
micrometer that reads out in braile?

Erm... yes, but how many blind machinists are there? It doesn't sound
like an easy profession for the partially sighted to me. Having to put
your fingers into the lathe to see where the tool was doesn't sound very
safe. Although you could doodle on things with an automatic centre punch
- braille graffiti!


Bruce


ABS