Topic: 1968 AC radiator support holes

[67gtasanjose]

I think a electrician's chassis punch will give a much clean hole then the hole saws that utilize a drill.

+1 Especially if you can't find a hole saw for sheet metal

In either case take time to deburr (s?) the edges or you might be sorry later. Not a bunch just enough to make sure they don't cut you or parts.

I have never used an electrician's chassis punch but it sounds like a great idea (probably a bit more cost though if it cannot be borrowed).
I have made good holes and bad holes with a saw in sheet metal over the years. I agree the quality of the tool is important. LOW AGGRESSION helps, scribing the sheet metal slowly and carefully.  In this instance, you can cut it slightly on the front' and then cut from the back side.
Practice and previous experience is a great teacher for learning how to cut a nice hole with minimum burring.

[67gta289]

The punch tool is awesome, have used them a lot, but not in this situation.  The most readily available ones are sized for conduits, so not in 1/16 or even 1/8” increments.  There are a lot of various shapes and sizes made for different devices (push buttons, indicating lamps, etc) that are mounted on a panel.   As Richard said these are much more costly than hole saws.   I pick them up when I find them cheap, just one of those habits hard to kick.

[1966KGT]

FYI, a good Sulphur based cutting oil will make the cut easier and less likely to "dance" around if you go holesaw, slow and easy.

[BKnapp]

I dont regret asking this question one bit. Thanks guys. New tools on the shopping list

Something like this might do the trick if you are lucky enough that it’s a standard size. An electrical material wholesaler or a-z rental might have them available to rent.

https://www.greenleestore.com/products/greenlee-7235bb-1-2-1-1-4-conduit-size-manual-slug-buster-knockout-punch-kit?variant=15440884163&gclid=EAIaIQobChMIzKPd396z4AIVy7jACh3jlAlcEAQYAyABEgK0HvD_BwE