Let’s not forget Motion Control Products, Marchant Dice and of course my company AXISCNC.

Quality, the ball screws coming out of MCP are a mixture of Chinese and Taiwanese products, these would also be coming from the same manufacture as the ones from MD.

Do you need traceability, MD offer full material and process traceability?

Ball screws are made in Taiwan and the lower cost ball nuts you see popping up on sites like eBay are coming out of China. The quality difference in the Chinese vs. Taiwanese is fairly significant, the Taiwanese being the better product.

Hardness,
Ground ball screws should have a greater depth of hardness through to the core of the screw, when they do the grinding process more heat is generated over a longer period of time and this heat is able to penetrate towards the core of the screw.

Rolled ball screws should be that bit more malleable, this is needed for the rolling process when producing the ball thread on the screw. The screw should then be case hardened; this would normally be done to a shallow depth and as a final machining process.

Lee