Lead screw question

[Dad1279]

Last time we used a leadscrew, we used a #25 sprocket on cim, and another on the leadscrew, coupled with a short chain. I believe we used a sprocket with a bore smaller than 8mm and drilled it out, 5/16" is very close to 8mm

If you really want to direct drive, andymary makes an 8mm hub:http://www.andymark.com/product-p/am-0320.htm

Or you could use a vex versaplanetary 1:1: http://blog.spectrum3847.org/2013/01...-mounting.html