EN 3 should be Ok for your shaft if it is a good fit in the bearing. Precision ground bar may be a better fit in the bearing.

Thor

Silver steel would be staggeringly expensive, even BMS in that size is pricey. I suggest using a cheap steel, thin as possible, and make a bush to fit whatever bearing you end up with. One source is a drive shaft from a rear drive car. The speed is a crawl so balance and straightness only a problem because it might influence the symmetry of the final product.

I suggest a major rethink to use a car front axle assembly with your table bolted to the brake disc. Apply the drive via a washing machine pulley fixed to the table and poly-v belt which is lighter, and more flexible than a v-belt. Also this will be taper rollers so no need for a thrust bearing. If you find you have a ripple related to the bearing being worn a new one would be far cheaper for a standard car fitting.

Edited By Bazyle on 25/11/2015 21:25:21