Last year, we saw [How To Make Everything’s] take on [DaVinci’s] machine for cutting threads. However, they stopped short of the goal, which was making accurate metal screw threads. After much experimentation, they have a working solution. In fact, they tried several different methods, each with varying degrees of success.

Some of the more unusual methods included heating a bar red hot and twisting it, and casting a screw out of bronze. The last actually worked well with a normal screw as the mold, although presumably, a good wood or wax shape would have resulted in a workable mold, too.

The real goal, though, was to make the DaVinci machine more capable on its own. The machine uses leadscrews and can cut its own leadscrews, so, in theory, if you improve the machine, it can cut better components for itself, which may make it possible to cut even better leadscrews.

The reality was the machine required some significant rework to correctly cut metal threads. But it does, as you can see in the video below. With some additional scaling of gears, they were able to cut a 20 TPI threaded rod that would take an off-the-shelf nut.

If you missed the original post on the machine, you can still go back and read it. Of course, once you have a threaded rod, you are just a few steps away from a tap, too.