rack and pinion

[luther]

hello can i use this for the rack and pinion i made the rack myself the sprocket is from a bike thanks

[rustamd]

I would be worried about backlash on that kind of set up

[luther]

no backlash felt when i move it by hand.

[rustamd]

another problem with using that sprocket is that your resolution would be very "coarse". Example: for one rotation of motor with that sprocket mounted directly to it, you would move 3-4 inches. You would have to make some kind of gear box to get lower ratio to be able to use that setup on router.

Even if using very small sprocket you would face problem of not having enough teeth in contact with "rack". Just my opinion.

[LeeWay]

I will say that yes, it will work. The concerns mentioned so far are valid. If you don't need great precision, then this may very well work for you.
It does seem to be a lot of work making that rack, though. I think you will get just as good or better results using the correct chain. You could tack weld or stretch it across this rack you made and it would wear better. The teeth are going to start wearing the rims on the holes pretty quickly with the rack. It would require adjustment often I would think.
Actual chains and sprockets sized like you might need are dirt cheap though.
Surplus Center is where I bought mine.

[luther]

know i understand to coarse .i was trying to make something cheap and accurate, any suggestion? thanks

[Cruiser]

I'd bet that the gear will want to lift itself up as it walks your rack, and if it does then it will bind and lurch with every tooth, or if you move axil center then you will have backlash, the only way for it to really be smooth is if the gear tooth form was designed specifically for the aplication, such as a real rack and pinion.

[massajamesb]

I know you are trying to save a buck and be ingenuitive, but....

A whole R&P setup from Carr Mcmaster will set you back about 175 bucks for 5- 4foot pieces of 20 pitch, 20 degree PA rack, and three spur gears. That may sound like a lot, but how many times do you want to buy something that "might" work, and take forever and a day to build all the mounts and brackets for?
Even using roller chain in a loop on each axis, like the links I sent up earlier in another thread, will set you back about 100 bucks and be much more user friendly than a bicycle sprocket.

Trust me, I speak from experience. I rebuilt my first machine 4 or 5 times before I finally decided to spend the money and buy the right stuff. I hated to spend the money, but I don't want to say how much I wasted on the way to the right parts.

[rustamd]

you can also buy cheap gear rack at http://www.stdsteel.com/gear.htm

also try www.econobelt.com for spur gears.

Alternativly you might try using timing belt and timing pulleys, which can be reasonably cheap.