Re: rotary hand encoder wheels with detent

--- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:

> Hi Fred,
>
> How about a 1, 2, 5 progression of jog increments?

The jog increments are usually called out in relation to the smallest
resolution that you would normally use in a program and which you
could reasonable expect the machine to move. I have not mentioned
any less than .001 because I am skeptical that home hobby machines
are much better than that. .0005 maybe on a Bridgeport machine in
very good condition, .0001-.0002 is very rare in a home made machine.

If you think in terms of your intended movement it is easier to
decide what values to shoot for. In my opinion, even though it is
common on commercial machines, I don't think that 100 detents is
needed. Most of the benefits of a pulse wheel can be had with a 10
or 20 pulse per rev mechanism. You want .001 increments so 10 or 20
times .001 is .010 or .020 per revolution. .01 increment is .1 or .2
and .1 is 10 or 20. .1 is probably too coarse with only 10 or 20
pulses and certainly is too much with a 100 pulse wheel and a 5 inch
Y axis.

This leaves you with resolutions of .001 and .01 which will probably
give you 75-85% of the benefit of a 100 pulse wheel at 1/4 the cost.

If you used an encoder like Sphero's you could use the push button to
toggle off and on, or off, .001,.01, and just add a push button or 3
or 4 position switch for the axis selection.

> And what is a Vlier?

A Vlier Pin is a set screw with a spring loaded plunger for a tip.
The pressure can be adjusted by turning the screw. Hence a
mechanical control for the feel of the detents. Since the plunger
has a spherical radius(usually a steel ball), you can use a drill tip
to make small dimples that work very nicely with a Vlier pin.

http://www.vlier.com

These are used in fixture design and building. They are carried by
all the major industrial suppliers like MSC, J&L, and also by the
fixture people like Reid Tool and Carr Lane.

Since Reid gave me a catalog back in the 70's when I was an
apprentice and since I still think they have some of the best gadgets
in their catalogs: http://www.reidtool.com/pdf/188.pdf

They cost $3-$4 each. Well worth not having to make a detent youself.

Best Regards,

Fred Smith
IMService