Re:Re: Making a punch die?

> Date: Sat, 14 Jul 2001 01:57:39 -0000
> From: "Joseph" <toybuilder@...>
>Subject: Re: Making a punch die?
>
>Thanks Fred.
>
>I sort of expected that the cutting edge had to be sharp and smooth.
>When you said that grinding the end is easy, but the sides might be
>hard, do you mean the part of the punch that contacts the to-be-
>displaced sheet metal (end) and the surface that travels along the
>sheared line (side)? Wouldn't having the side relief take care of
>the latter?

No. You want to prevent the punch *and* slug from jamming into the die. The punched hole is smaller than the slug you punch out. It's not really, but the edge is not perfectly straight so there is an interference between the slug and the hole because of the jagged /angled cut edge. The same reason that you cannot push the slug back into the hole in the sheet, you can't push the slug out of the die. The die relief may let you tilt the slug at an angle & then you can get it out with a pliers (if the hole doesn't go all the way through the die body)

>
>Hmmm, I just realized that maybe you mean the inner wall of the die
>for the "side".
>
>In my case, I'm making these dies for light-duty occasional use on
>plain aluminum sheets (and plastic too), so I'm hoping that a little
>bit of slop will still be okay.
>

If you allow more slop than necessary, you will start to get a smear burr or even de-formed edges on the sheet. That's OK, till you end up spending more time reworking the punched holes (not to mention the time to make the tool) rather than if you had just used some double sided tape and a clamp or two and milled the hole.

Best Regards, Fred Smith- IMService
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