On Wed, 29 Apr 2020 11:14:53 -0700, tabbypurr wrote:

On Wednesday, 29 April 2020 11:29:12 UTC+1, alan_m wrote:
On 29/04/2020 10:14, tabbypurr wrote:

Interesting. Last time I used those, long ago, they severely
distorted the sheet they were punching. Is there some way to avoid
that?

https://www.youtube.com/watch?v=RxQE6mtRWCk

I've used them in the past without problems but are you sure that it
was the punch causing the distortion or you applying a sideways force
to the whole punch assembly and twisting the metal.

the metal was in free air, and the punch tightened with spanners. The
problem is that the punch cutting edge is not flat, so as it pushes 2
parts of the potential hole, the whole sheet wanted to follow it & get
very bent. I know punches sometimes work, but IMLE with them you need a
lot of surrounding metal to resist that urge to bend horribly.


You can get a Q-MAX Thrust Race to make winding in the punch much
easier and possibly help with with any unwanted forces you apply to the
structure you are working on

sure, not sure it's worth it for 1 or 2 holes.


NT

Cor! I used to cut holes in folded brass chassis for B7G and B9A valve
bases with Q-Max cutters sixty years ago......didn't know you could still
get them.