Re: Making a punch die?

--- In CAD_CAM_EDM_DRO@y..., "Ian Wright" <Ian@i...> wrote:

> Hi,
>
> Just a thought on this - how are you intending to hold the punch

and die

> while using them? Most of the simple 'chassis punches' use an allen

screw

> through a pre-drilled hole to pull the two parts together but this

would not

> be very convenient for a DB25 shaped punch because of alignment

problems

> between the two halves. I suppose there would be a chance if you

used two

> allen screws towards the ends of the die but would you be able to

use strong

> enough screws to withstand the forces needed to drag the whole

length of the

> side cuts through the aluminium. At the very least you would need

to shape

> the bottom of the punch so that the cut is progressive i.e. it

starts at the

> middle and finishes at the ends or vice versa.

Ian,
That's the correct way to do it.
Your die is just a hole / slot in a piece of metal with a bottom
secured to it. The punch is a mirror image but you grind the top face
away from the centre, both sides at about 10 to 15 degrees.
You then need three holes in the punch and die, one centre one that
does the pulling and two small ones at each end to locate the set.
You then need a drilling jig for the chassis or part you are doing.
Idealy this should be the same jig that used to make the punch and
die.
To use drill the three holes using the jig then assemble the punch
and die on either side locating with pins through the small holes
then just tighten the centre screw.
We used to regrind the simple bought round punches this way as it
made things easier and less pressure was needed. I've put 2" holes
through 1/16" thich steel sheet this way with no problem.

John Stevenson