Machinist Jack with M8 Bolt

A “machinist jack” is a tool to support overhanging work pieces, e.g. on a milling machine. It reduces deflection due to tool pressure. The second photo is a demonstration how a jack might work.

This design is the result of me wanting to test Dan Kirshner's threads library in OpenSCAD. The library is very comprehensive in its support for metric threads. But the pure amount of faces added to a project increases render time significantly! Although the library takes clearance into account, my printer lacks the precision to form perfect threads. Therefore, I ran a tap through the threads to clear them. After that the bolt fit perfectly.

I have some coarse (pitch = 1.25mm) M8 bolts, around which I designed the stand. Basically every bolt of any length will do. The length of the bolt defines the range the jack can support.

Edit - I realized that I forgot to make the threads customizable. Use V2, if you use anything but M8. It lets you specify the diameter and pitch.