The servos on my mill have sinusoidal encoders which are not
compatible with most CNC control stuff.

I am looking at various options.

One is to make a converter to convert sinusoidal to quadrature. It is
a pain in the butt to do due to lack of documentation on what wire
does what.

Another one is to reuse a converter board from the existing Heidenhain
controller. Same issue as above. (and I do have documentation, it just
does not say what is what).

I have opened up one of my servos to see the shaft. It is a 10mm
shaft.

For that size, US Digital has suspiciously cheap encoders E7P:

http://usdigital.com/products/encode...otary/kit/e7p/

They seem like they will fit, however, I am slightly surprised at the
price.

I Wanted to know if anyone has any suggestions, as I do not want to go
a wrong way.

i