How to build HP-41C custom overlays?

[rprosperi]

I'm not sure if this is possible/applicable to any of the printing / construction techniques you guys are exploring, but keep in mind that 2-sided overlays can make it much easier to carry multiple overlays, mounted right in the keyboard.

To do so, you have to make 2 small adjustments to the key hole sizes in the template design.

#1 Remove the vertical post between the 2 rightmost key holes in the 4th row (between the "RTN" and "Exit" keys in the example in the photo) creating a 2nd double wide hole on the 'other' side.

#2 All the key holes in rows 5-8 need to made slightly wider as the numeric keys are wider than the operator keys and when flipped, will not fit right unless slightly widened.

#2 is easier to see than explain, just flip over an existing overlay and you'll see what I didn't explain well.

This clever technique is not new and goes back to about 1980, for overlays made by Jake Schwartz and others in PPC, who pioneered paper overlays with hand-written labels. I still have a stack of them and and happy to send a sample if that would help, but I suspect just the above comments are all you guys need.

Good luck and please continue to share your results as they improve, and also if you would be willing to make some for other members (at a reasonable cost, no one should expect something like this for free).