Ideas for fitting leadscrews

[irving2008]

Been playing around with ideas for fitting the 10 x 2 leadscrews to my DIY CNC mill. Conventional wisdom machines the end of the lead screws. I dont want to do that but I still want to make use of skate bearings for support and some form of thrust control. So I have come up witha ferrule arrangement as per the diagram. This supports a circlip/thrust washer arrangement at the stepper moter end and a threaded element with thrust washer and back-lash adjusting nut (and ideally a lock-nut as well) at the far end. The ferrules are retained on the leadscrew by a 4mm hole drilled through the ferrule and the screw. This will be pinned or the ferrule could be tapped for a 4mm grub screw. The skate bearings are held in bearing blocks machined out of some suitable material (Nylon or poss MDF) set so they are opposing each other.

The other pics show a lash up of one ferrule I made today on my lathe out of some scrap. I need to get some 15mm rod to do the real ones, and grind up some sharp machine tools. The test piece is too short and the finish and accuracy arent great because I dont have any sharp machine tools and there is far too much back-lash in the cross-slide on my lathe, but it fits. Its the first thing I have ever made on my lathe though :)