[Beefy]

I'm noticing a lot of rack and pinions for sale are made of either mild steel (which I think is 1018) or 1045 steel. In their sold state they are not hardened, and I don't see anyone going to the extent of getting the teeth induction hardened (if 1045) or anything like that.

Do the gear teeth not wear out quickly like this. Has anyone been using this type of rack and pinion for a long time and noticed any wear.

Thanks,

Keith.

[cheetahcnc]

The mild steel on my router meshed nicely after a while. Wouldn't hardened parts be more noisy and take longer to mesh? Most of the regular rack gearing is not extremely accurate to begin with anyway. As long a your pinion gear/motor combo has room for adjustment, it should be fine.

Jim

[WSS]

It also depends on how everything is sized for the job. Too small a pinion (face width) and it might wear quick, too big and you've got drag. I am using mild 3/4" FW pinions right now (1.125" PD) on our nema34 servos from Torchhead and big 12:1 GB's from Global motion tech. (nice gearboxes BTW). The pinions and rack are 24 pitch and 24 deg pressure angle. This combo is quiet and the teeh mesh well and tend to pull into the rack more than the 14.5 PA rack/gear combo.

We had our pinions cusom made for about 70 yankee bucks each (thats about 20 aussie bucks right? LOL)

WSS

[Beefy]

Thanks for that input lads. As always I'll be going overkill on the sizing but I'm going to have probably 900 oz-in dual motors driving the gantry, so hopefully that will negate any drag issues.

My reductions will be 6.22:1 but with pinion teeth just over the 20 mark, and the associated larger diameter with bigger rack, I'll be getting near the ideal 1 inch per stepper motor revolution. If I ever build a bigger table I should be well set up with the drive gear. Maybe I can use the gantry to pull the car up on the wheel ramps if the engine's not going.

Cheers,

Keith.