I’m still a slave to the books, but I occasionally decompress with a little eBay browsing. I’m accruing material for projects I’ve got planned for my glorious post Core Exam days, but I couldn’t resist giving one cool little tool a test drive.
A common need in making brewing hardware is a hole in sheet metal for a valve or instrument. You can buy a pot with the parts already installed, but you can also do it yourself. So far, I’ve just been using a step drill bit. This certainly gets the job done, but it takes forever, leaves a lot of metallic swarf that’s hard to clean, and leaves a jagged edge that takes a lot of sanding.
The hole punch is a better tool. This is a bolt with a threaded punch and die that cuts a clean, perfectly sized hole. The Greenlee brand is popular but expensive; the 7/8″ punch required to make a hole big enough for a 1/2″ NPT bulkhead costs over $80! I lucked out and found a used one for $13 on eBay, so I pounced.
Drill a 7/16″ hole for the bolt, place the hole punch, and tighten down until the punch passes into the die. The punch is definitely the way to go.
This hole is in my hot liquor tank for a thermowell. A little Teflon tape and silicone sealant goes on the outer threads, which are 1/2″ NPT. A 13/16″ ID x 1 1/16″ OD silicone o-ring goes into a 1/2″ NPT locknut and will secure the thermowell on the inside, making it water tight.
There we are. A newly mounted thermowell. A thermometer with 1/4″ threads to match the thermowell goes inside.
The nice thing about the thermowell is that I can later install a digital thermometer when I want to automate the hot liquor tank.
All that’s left is to pressure test it.
No leaks! Now I want to find a 1-1/4″ hole punch to put electric heating elements in my pots, but that will have to wait. Back to the books. Just a few more weeks until the big test.