Re: [CAD_CAM_EDM_DRO] Re: mouse encoder?

From: "Tony Jeffree" <tony@...>

>
> Nothing to stop you from making your own discs if you have a suitably

small

> end mill. I made a 60-slot disc for RPM measurement using a 1/6" end mill

&

> the 3" diam platter from a defunct hard drive - worked a treat. You can
> see some photos of that plus my PIC-based RPM meter at:
>
> http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/Tony%27s%20files/RPM/

Tony~!

Simply excellent, Tony.
Bravo.
This is indeed *exactly* what I was thinking.
Did your parts come out of a mouse?

Also, a word on the slots.
In thinking this over, it occurred to me that one could just as easily
(if not more easily) simply drill holes in the disc.
Upon looking at it, it would appear that they put slots in
only to make it easier to account for not-so-perfect alignment.
If one were to calculate the width of the slot, pick a suitably close
drill diameter, and drill the holes with a like distance between the holes,
wouldn't this do the same thing, and be much easier and quicker to make?
(in other words .031 holes, .062 apart)

I'm thinking that with a 200 step per rev motor, you simply plot the bolt
hole circle
for the correct size disc and hole, and start drilling away.
This seems much simpler and quicker.

Am I wrong here?

Weyland