I believe the actual dia. of the disc makes no difference, just use whatever dia it is for the calcs. I see no need to change the disc, just widen the slot.
(correct me if I'm wrong here Hood)
I tested 1 mm window, maxed out around 500, then went whacky.
2 mm ..around 1100
3 mm 1700
5mm  2600  maxed me out

10 mm would be a great choice for width (mine is   8mm  (dang smiley head)

Russ


modified for the dang 8 then ) smiley head

Ah Fastest,
 you are using a diffuse reflective sensor ? ?

The C3 is a bit different. It has a dedicated circuit board with Schmidtt triggers and a through-beam type sensor. It improves the response and the output.

Russ

I don't use the C3 and that could be the difference. I have one of Homan's boards, not sure of the sensor. I assumed it was an optical sensor of some form.

Hi Fast,

I would guess that you would be better off to paint the pulley flat black with the exception of a 1/2" shiny spot. Or even better, a small piece of the special reflective tape.

Your sensor being ON for the large degree of rotation leaves it more susceptible to inadvertent switching.
Much less likely to pick up an anomaly by watching the black disc for the relatively narrow reflection.

Typical diffuse reflective sensors that I've used generally work most reliably this way.

Peters may be different though, I haven't researched his model.

Regards,
Russ

edited for spelling

Russ, yes the disc dia wouldnt make any difference.


Hood

I put a C3 on my mill and slapped on a black-painted CD with a (approx) .160" hole drilled in the outer edge.  It works perfectly up to the mill's 3200 rpm top speed.  I'll have to double-check the hole dia. to be absolutely sure.

A big thank you to all who replied.
It came down to 2 simple items:

1. The "Disable Spindle Relay" box must NOT be checked.
This box is found under (Ports & Pins / Spindle Setup) Relay Control

2. You need to turn on / click the "Spindle" button to get the RPM to display.
This is one of the large main control buttons found at the bottom of the Manual and Auto screens.