leadscrew bearings

[Jawno]

Wondering if anyone can help guide me in what type bearings to use on a leadscrew. On the Z axis. I've heard that I need to use thrust bearings. Can I just go into an auto parts store and ask for some thrust bearings with the right diameter and use them? Some machines I see only have bearings on the top end. Seems like it would be better to have bearings on both ends but what do I know? I don't want a lot of backlash. Just not sure what would work.
My leadscrew is a 1"-5 ACME about 12" long. The bearing surfaces are about 5/8" OD.

[BillTodd]

Whether the Z axis will require thrust bearing top and bottom will depend on you application. If the weight of the Z axis is sufficient to overcome all the (upward) cutting forces, then you could get away with only one trust bearing (since the force on your screw will always be in one direction).

As to the type of bearing (ball thrust, tapered roller, or plain deep groove ball bearings) , that will again depend on the weight of your z axis and the forces the lead screw is under.

Give as much information as possible and the people here will help you

Bill

[ger21]

I used skate bearings on my 1/2" acme screws. On my newer machine, again with 1/2" acme, I'm using angular contact bearings.