On Sunday, 3 May 2020 00:42:58 UTC+1, Roger Hayter wrote:
tabbypurr wrote:
On Saturday, 2 May 2020 11:24:00 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Friday, 1 May 2020 11:34:24 UTC+1, Dave Plowman (News) wrote:
In
article ,
tabbypurr wrote: On Thursday, 30 April 2020 14:56:33 UTC+1, Dave
Plowman (News) wrote: In article
,
tabbypurr wrote: On Thursday, 30 April 2020 11:37:57 UTC+1,
Dave Plowman (News)
wrote:
In article
,
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?

Get some decent quality ones? If the tolerances are poor, it
won't shear accurately.

The ones I was using were the Qmax you recommended.

What were you cutting?

boxes, mainly sheet ali. IIRC they were fine in plastic.

I've made loads and loads of holes with them in various
materials and not had a problem with distortion. Assuming you
took care using them, as it would obviously be possible to bend
sheet steel by the action of turning them with a spanner, etc..

With the metal in free air it's not going to see problematic torque.

Given you'd normally hold the work while using the cutter, not so sure
about that.

But it sounds like you were using a worn cutter. If a common problem.

They were brand new. I explained why it happened several posts back..

Even the best tools need skill to give good results.

Sure. The relevant skill in this case being awareness of what cases
punches are not suited for.


NT

Another error is using them too near the edge of a thin sheet. DAMHIKT.

That is precisely the problem. Hand operated qmax Punches use a non-flat cutting edge to keep peak forces within practical limits for human, screw thread & spanners. So the metal is at once trying to conform to both flatness and the bent steel created by the punching action. The lack of a large enough thick enough sheet causes distortion, sometimes severe enough to produce only scrap. That's what happened.

And in the current situation, once again holes are required near an unsupported edge. Don't really want to write off the CU, so the punch option seems risky.


NT