Does anyone have or have access to any round knockout punches used to put clean, round, burr-less holes in metal? Looking for them in regards to the brewing system build.

Thanks
-Dave Toews

I have a .875" (1/2" electrical knockout).

I also have an electrician's step drill which does pretty good in sheet metal. It's about 3/8 to 7/8.

-Jim Hart

That might work. I would need to find the corresponding ball valve fittings, as most of the plans I've seen are for 13/16th (8.125") size.

How thick is the metal? Harbor Freight had a couple of cheap punches for what they called light metal (I am guessing tin/aluminum) and starting with leather.

I bought a set, but they are cheap, so steel would be right out from what I can see.

The other option is to machine a punch to spec, and if it is something you think we could sell to other brewers, we could have our first Hack Factory product to sell.
(ok, back to reality) the whole punches I have seen are just tapered to spec, so even with our nicely refurbished metal lathe, we should be able to cut a stainless steel rod down and then hollow out a core.

The metal is stainless steel keg walls. Not sure the HF punch would do the job.

Ya, I would think it is a bit cheap to work.. And with out a way to block the back of the hole, a hand made one may not work either.