Re: Helical Couplings

Bill,

It's my impression that helical couplings are not the best for use in
a precision machine. I notice the listing in my McMaster catalog
says "with little wind-up or backlash". Doesn't that imply they
have wind-up & backlash?

How about the bellows type, they are listed as "no backlash". Of
course, they cost more than 2X as much.

This coupling problem is one reason I feel a number of manufacturers
use a cog belted arrangement. I don't recall ever looking at the
couplers on any large production CNC's to see what they're using. Do
you know?

thanks,

Doug


--- In CAD_CAM_EDM_DRO@y..., "William Scalione" <wscalione@n...>
wrote:

> Anybody here have any 1/2" helical couplings in their junk box they

want to sell?

> I figured I would ask here before I spend the big bucks for new

ones. Please

> contact me ____OFF LIST____ at scalion@d... Thanks.
>
> ps. these are needed for servo motors, I got running with gecko

G340 drives. If

> anyone is considering stepper motors, I would strongly suggest

using servos instead.

> They are much smoother with no missed steps common with steppers.

The drives

> are cheap enough for the step and direction servo drives and the

motors can be

> had for a lot less than stepper motors of comparable size on ebay.

I can get 350

> inches per min on my machine now, and I haven't even tuned the

drives yet. This

> is much better than I could get with steppers, and I had good

Compumotor 175V

> S drives microstepped to 1000 ppr. Thanks Marriss for the great

drive.

>
> Bill
>
>
> [Non-text portions of this message have been removed]