FILENAMES:

encoder.jpg

DESCRIPTION:

This is a picture of the shaft encoder that Richard Everett added to his
Sherline mill. Posted by Richard Everett (DebEverett@pobox.com)

Richard provided the following description:

>Here is a picture (encoder.jpg) of the quadrature encoders I have
>mounted to the rear stepper shaft of the x and y axis of my Sherline
>cnc mill.  The resolution is adjustable from 400 to 1600 counts/rev.
>
>Richard

AND --- posted to the rec.crafts.metalworking newsgroup

Title: encoders for cnc stepper motor mills
Author: "Richard Everett" <everett@oz.net>
Date: 16 Sep 1997 02:00:53 GMT

I have posted a picture (encoder.jpg) of the $39 encoder I mounted to
my Sherline cnc mill x and y axis stepper motors.  As you can see, it is
small and inoffensive, although I now have two nice engraved Sherline
handwheels sitting in a drawer (can't fit them on the rear shaft of the
stepper motor with the encoder attached).  I would suggest people ordering
new PacSci stepper motors to inquire about an extra long rear shaft (1.25
inches should do) if they want encoders AND handwheels.  Two $11 LS7166
chips, along with two 74LS138 3 to 8 decoders provided an easy interface
to an 8 bit ISA bus (using a Radio Shack ISA prototyping card and wirewrap
tools).  Total cost for the x and y encoder add on was about $120.  It
works better than I ever would have expected, giving 1600 counts/rev in
the X4 mode.  Somehow, the alignment of the encoder disk to the stepper
rotor was not a problem at all. Go figure.


Later,

Richard