DIY Paper Tape Punch - Mechanism diagram?

[Tony Duell]

>
> > Be warned that making any paper tape punch is going to be non-trivial.
> > Grinding and hardening the punch pins and making the die block for
> > them to run in is quite a difficult machining task. And that's needed
> > what ever drives them.
>
> True.  At least the pins may be something you can buy: pin gauges are made to extreme precision in 0.001 inch increments and may well work.  Or metal dowel pins, if

I seem to remember that in some cases the pins are not flat on the
business end. And of course they have to be hardened, but gauges are
likely to be.

they come that small.  But that still leaves the die block.  Would
drilling and reaming be good enough?

Probably. The pins need to work smoothly, but with no excessive gaps
or they won't punch cleanly. Remember the die has to be made in 2
parts accurately aligned to leave a slot for the paper tape to run in.
And of course (the relatively easy part) you need 9 holes in a
straight line at 0.1" centres. You then need to harden the die without
distorting it.

It's not impossible (after all these things _were_ made once). But
it's not the sort of thing you can do with just hand tools I think.

-tony