Has anyone seen anything on stopping backlash with rack and pinion drives?

Salty,
I have heard of manufacturers doing 3 things,
1- using a pinion gear split in half so you can preload the 2 halves in opposite directions.
2-Using a helical pinion & Rack.
3-Using 2 pinion gears and preloading them in different directions.
Check for machine design magazine online and browse around in there, lots of goodies in there.

thanks for that I will have to look around

Shopbots use a turnbuckle to pull the pinion into the rack. The pinion being direct mounted to the motor, mounted on a pivoting plate. Other people have used springs to do the same thing.

Gerry
I was thinking of eother spring loading the rack (possibly a hard way of doing things) or more probably I will try to spring load the stepper

But I do like the idea of a mounting plate and sring adjustment

Did you see the previous post like this?
http://cnczone.com/forums/showthread.php?t=6815&page=2&pp=8&highlight=rosta
This Rosta item is a central pivot tensioner.
Al.

Al, I got a round dozen of those Rosta gizmos after seeing your earlier post on eBay for cheap. They seemed like they'd be handy for a lot of tensioning tasks. Haven't used them yet, but they are slick little boogers.

Best,

BW