Re: Still not started

Steve Gunsel wrote:

> From: Steve Gunsel <gunsel@...>
>
> OK, I've got the mill drill, a 9" SB lathe, computers (mostly old but
> probably plenty good for this), and the software appears to be available.
> I guess the next step is to locate some suitable stepper motors and then
> build mechanical mounts and the electrical motor drive units. Questions:
>
> Just how big of a stepper motor is really needed (x, y, z, cross feed, etc.)?
>
> Where can the stepper motors be obtained at a reasonable price?
>
> Are servos preferred?

Well, as a bit of a pioneer in this area (for home shop use) I might just
be a bit biased. But, I think they are worth the effort (and cost).
The advantage is that you can have just about infinite resolution (limited
only by the cost of whatever encoders you can come up with) with no
affect on maximum rapid feed rate. You don't have to worry about
losing steps. Even if the machine crashes, or binds up, it won't lose
position, it will declare a fault and stop.

> If so, where can servos be obtained?

Well, the motors themselves are everywhere. They are used in all sorts
of machinery, but some of the best motors for Bridgeport-size applications
are from 1/2" mag tape drive reel motors. The direct-drive reel motors
are optimized for high torque at low speeds, just what we need.

As for servo amps, they are floating around on the surplus market, too.
I ended up building my own, as I couldn't find any suitable units when I
needed them. I made a group project, but nobody else has completed
theirs yet, as far as I know (I expect I'd get questions, etc. when they
get close). I still have some of the boards left.

> Actually, I think the biggest question is how to find the time to play more
> with this stuff.
> Thanks. BTW this is one of the best forums I have ever seen!

I was lucky to have a lull in my home business at the right time to
throw my CNC together.

Jon