Re: sprockets?

Hi Jeff,

sounds good.

since you are just setting up and testing things you have the fun
time of trying out different set-ups.

if you are using a 200 step per rev stepper and a 10 TPI leadscrew on
a 1:1 your 200 steps equate to 2,000 steps per inch or a theroetical
0.0005 " accuracy.

I think a lot of us shoot for the 0.0005" as the first step with the
expectation that better than one thou is really great.

If you use a 4 TPI with the same set-up you get 800 steps per inch.

The less steps per inch, the faster the table travel and vice versa.

Since timing gears are relativly cheap, I would look at getting two
sets, something on a 4:1, and a 2:1. With those you would have 4
gears and could actually get many combinations using those gears.

Dave

--- In CAD_CAM_EDM_DRO@y..., "jeffgnu" <jfbell@e...> wrote:
> I am looking to get into CNC and I am in the process of building
> myself a small router table. I will be using a trim router and some
> stepper motors, Which are Fuji's NEMA 34 , rated at 150in/oz. This
is
> going to be a small machine with very limited capacity. It is just
> going to be a learning tool, so no need to spend high dollars. Just
> something I can play around with for the time being.
>
> The stepper controller is a Camtronics.
>
> I am looking for some sprockets and timing belts to drive a ACME
> threaded rod and with a anti-backlash nut for the Z-axis. What would
> be a good ratio from stepper to rod sprockets? 1:1, 1:2 The stepper
> have a 180 S/R.
>
> How thick of a timing belt should I be looking at? 3/8", 1/2" or ???
>
> Thanks.