I'm thinking I want to build myself a kettle with a heater, a valve and a cooling coil. So four holes. probably, two different sizes

Perusing the electricbrewery.com site, they stress the need to use a chassis/radio punch, but they're expensive. For the same price, I could get one of the sets sold on ebay or harborfreight.

Reading around other sites, I read the elements typically are 1" National Pipe Straight Thread. This measures 1.3" which is the size the conduit punches produces.

Given the standard conduit hole sizes, some washers and a high temp o-ring, can I get a good install using this combination?

Is there more than one size heater element (the mounting portion)? Different threading? something else I'm missing?

  • just follow the instructions on the site - the whole build costs upwards of a couple of thousand dollars - with that in mind, saving 20 or 30 bucks buy using an inferior tool seems little to gain when it's probably the most critical part of the work. Although I made various additions to the control panel and other parts of the brewery, I followed kal's advice to the 't' when it came to the kettles.
    – mdma
    Commented Feb 5, 2012 at 21:43
  • the comment above was meant to have 'my advice is to...' in front...seems a lot harsher without it.
    – mdma
    Commented Feb 5, 2012 at 21:50

3 Answers 3


You could use a conduit punch if you knew exactly the size of the hole it makes.

look for Q.MAX punches - they're radial punches and much less expensive than the greenlee punches and are available all over the net, and ebay. I've installed elements in my kettles with these punches with no problems.

You might also check on the electric brewery forum to see if anyone can lend you the tools. I would, but return shipping from norway probably isn't all that economical.


As long as the hole is the correct size and has clean, flat edges, however you make it is pretty unimportant. I used a step drill bit for my kettles.

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1" NPST is the most common thread I've seen for elements. There are some others out there, but just check before you buy.

The only issue I can think of with a conduit punch is it not being made to punch stainless, which is much tougher than the soft metal used in conduit boxes.

  • You'll need a 1 3/8" step bit to get the right size for a water heater element, and make sure you oil your bit! Those guys are NOT easy to sharpen and drilling thru stainless steel will take its toll on a $50 bit. Commented Feb 3, 2012 at 15:07
  • @jeremy: That's why I got a $10 one from Ebay :) Yes, plenty of oil. I sharpen it with a flat diamond hone. Easier to sharpen than a twist bit, in my experience. It's not a better solution than a real knockout punch, but quite a bit cheaper and more versatile.
    – JoeFish
    Commented Feb 3, 2012 at 15:39

I used a Greenlee 1-1/4" radio (round) punch which is exactly the right size for 1" NPT heater elements. I used a Camco, but I'm pretty sure they're all the same standard size. I made the holes in kegs and the punch worked perfectly. For a kettle a step bit might work, but the punch will go through like butter and you'll have a perfectly round hole with no flashing like you will have with a step bit.

  • +1 agree with this, bill, the punch is the way to go. The last thing you want to do is ruin a few hundred dollars worth of kettle by using a tool that isn't the best fit for the job. An experienced metalworker could probably tidy up the resultant flashing, but for a 'just get the job done' solution, the hole punch is the way to go. I used a step bit to make the holes for the hole punch, and I'm glad I didn't have to clean that up - just let the hole punch chew through it.
    – mdma
    Commented Feb 5, 2012 at 21:37

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