Sourcing a Scale

So, you want a 1/2 inch scale that is 6 inches long (or wide, depending on your perspective), graduated in 8ths, 16ths, 32nds, etc. and 1/10ths and 100ths?

Well, if it needs to be graduated in tenths and hundreths of a meter (you really didn't tell us), then this might do the trick:

This is the Starret #306441.

Decimal inches, sorry, I don't know of one. These guys http://www.schlenkerenterprises.com/index.html will custom make rules for you... Probably Undoubtedly will have a minimum order quantity.

If you are wanting to measure gaps with significant accuracy, then look up "taper gauges". I'm sure that STARRET and Mitutoyo make them. They are used extensively in auto industry to measure gaps between doors and other body panels.

Depending on the grade of the taper they can give remarkably good resolution.

GA dgibson -- I particularly like the Starrett 423. Also as mentioned by Just an Engineer in reply #4, Starrett makes three taper gauges I'm familiar with and three I'm not. The 270 Taper gauge is good for small slots that are long enough to fit into. The other two in my tool box are the 269 A and B. Very handy for measuring small openings that are deep enough to allow the narrower ends of a given gauge leaf to fit in. For shallow features or surface measurements; however, the 423 approach is sometimes the only way. Problem here is that the accuracy depends on how good your eyes are in comparing features on the gauge scale with features on the object being measured. If you want to search for the others the Starrett numbers are 245, 245M, 269MA, 269MB and 267 (the "M"s stand for metric).

Sometimes the only way is to employ optical approaches such as a reticle in a microscope or hand magnifier or a laser spot that can be moved a calibrated distance by a linear slide mechanism.

I have a small laser edge finder set up on my milling machine. This can measure using the calibrated axis motion of the machine tool to within about .002 inches by eyeballing the alignment of the laser spot with the object being measured. These laser gadgets are not all that expensive; like US$100 or so and come with magnets to hold them on machine surfaces.

Ed Weldon

Looks as though you need one of these:-

A couple of these:-

And one of these:-

The first two pictures are from Starrett's website so It's worth contacting them.