I’m unsure whether it would be suitable for your proposed ring scale, Roger, but I’ve had good results with printing onto clear self-adhesive decal sheet which is then applied to the item in question.  For example, when I made a simple indexer, I needed to put the numbers around the periphery of a collar.  I started by hand stamping, but was dissatisfied with the result. In my case, I merely measured the diameter, calculated the circumference and drew the scale in a CAD program, then printed this onto the decal film, cut it out and stuck it to the collar.  The result can be seen in the photo below:

The printed numbers are the larger font.  (The division lines were engraved on the mill using a rotary table.)  I no longer have the indexer in my possession, so can’t vouch for its longevity or otherwise.  I did not attempt any protective covering of any sort as it was intended to be “temporarily permanent”.

I gather from your description that your requirement is for a “flat” scale, so that should be easier to produce.

These days, in the absence of a 3D router or cnc mill, I’d probably try 3D printing it.

John

I suggest hot plastic laminator as often used for outside noticeboards etc. However cut the paper to size (circle) before laminating leaving a clearance so the plastic seals plastic to plastic else the exposed paper edge will wick water in. Then cut out and stick that to the Perspex with Bostic clear or some-such.

I should perhaps add that the usual 3M film is very thin, unlike “ordinary” double sided tape.

This would make an interesting short article for the magazine.

Neil