A Bolt Guide

I rarely use my Curta for caculations.  But I do often demonstrate it.

That usually entails opening it to show the inner details and how it works.

To open it, one has to remove two long, thin bolts from the bottom.

But, as you know, it is very difficult to put these bolts back in: they are long and must be held precisely over the holes, which are quite far down.

I designed and 3D-printed a guide for the bolts, and that helps a lot.  Here it is:

It does not alter the machine nor requires anything special: it is a simple insert, sitting inside the bottom, completely invisible:

If anyone is interested, the 3D .stl file is available,as is the design for the Cinema4D app.