cutting holes

[Matt Haines]

>If you really want to get whole hog into chassis building the tool you
>want is called a punch (eg. slug buster) that works with a ratchet or
>hydraulic driver.  You drill a pilot hole, assemble the punch to go on
>both sides of the metal, and crank it up until it breaks through.  There
>are punch sets that can go through even heavy steel and fiberglass.
>Small round punches (ie. they make circular holes) for 20 gauge steel are
>around $20 each, while more exotic shapes like D-connectors and large
>meter holes can go for several hundred dollars per punch.
>

In all the catalogues I've looked at, the punches will not handle 1/8"
aluminum. Even on the 5000lb presses they sell, 1/16" is all it will do.
Have I missed something?

>A more cost effective solution for dealing with large holes might be a
>hole saw.  That is what I use.  I back up the metal sheet with a piece of
>wood and cut from the inside out.  After that I deburr and touch up the
>hole with a file or dremel tool.  This isn't the most elegant solution,
>but it does work.
>
>Anyone have any ideas on how to cut rectangular holes for IEC connectors??
>

The reason I asked about the nibbler is because I've found a place that
will supply the aluminum and will also drill, for about $60/hr. They figure
they can do maybe three panels in that time, and I'm willing to pay that.
I'll still have to finish it myself of course, but it's cheaper than some
of the alternatives, and saves a lot of time compared to drilling myself.
Plus it'll be tidier.

The one question I had was about the 'ovals' that are drilled for rack
screws on each side. I thought perhaps a nibbler might help, but probably
not. I was thinking perhaps having the metal shop drill two holes for each,
that overlap. I'd file down the surface to make it more ovally. I don't
know if they can drill overlapping holes though, I've not yet been down
there with a design.


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Matt Haines  haines at apc.net         .       .       .       .
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I am not a grotto blaster.