> On Dec 2, 2024, at 4:00 AM, David Wade via cctalk <cctalk@classiccmp.org>
> wrote:
>
> Folks,
> I have been trying to restore a manual card punch. The type with 12 "Buttons"
> or "Plungers" that operate a lever which pushes a punch "pin" through a die
> to create a hole in a card.
> Its almost identical to this one:-
>
> https://www.computinghistory.org.uk/det/38019/ICL-Hand-Key-Punch-Card-Machine/
>
>
> so despite lots of cleaning some of the pins stick down. Does any one have
> any suggestions how to clean the small square slots?
> Any idea how the holes were made?
>
> Dave
> G4UGM
Do you mean the rectangular holes that guide the punches, or that receive the
punch below the card (the die)? Or are there square rods that carry the
buttons, in a square hole?
The obvious solution would be a solvent. Paint thinner might work. If not,
you may want something stronger, but if so you'd need to remove any plastic
parts (like the keycaps). Laquer thinner is potent, I use it a lot, but only
on insoluble items.
Rectangular holes can be cast, or machined with a broach. The same goes for
square holes, but in addition it's possible to drill square holes, using
triangular drills. Watt Brothers Tool Works has made these for ages (see
https://www.scribd.com/doc/67999953/Watts-Bros-Manual).
paul
