Very confused about metric/US measurments for installing piping in my kettle

[Remos112]

So I decided to upgrade my kettle/mashtun, it has a 2000W heating element and an SS Thermowell +lcd thermometer and a Filterhex installed. I recently bought a pump a ball valve and 4meters of silicon tubing to keep me busy for a while. I am breaking my brains over some measurements though.

I bought a 17mm carbide drill from SS to fit the thermowell and since this drill is quite expensive I would love to use it again.

I would like to install a hose barb and a ballvalve in the kettle and everywhere I read they recommend a 13/16 or 7/8 hole which is roughly about 20-22mm. A 1/2" Hose barb or thread is 12.7 mm though what am I missing here? Do I really need a punch that big, or will my 17mm drill bit do the job?

Much thanks in advance!
Remi

 

[GilaMinumBeer]

So I decided to upgrade my kettle/mashtun, it has a 2000W heating element and an SS Thermowell +lcd thermometer and a Filterhex installed. I recently bought a pump a ball valve and 4meters of silicon tubing to keep me busy for a while. I am breaking my brains over some measurements though.

I bought a 17mm carbide drill from SS to fit the thermowell and since this drill is quite expensive I would love to use it again.

I would like to install a hose barb and a ballvalve in the kettle and everywhere I read they recommend a 13/16 or 7/8 hole which is roughly about 20-22mm. A 1/2" Hose barb or thread is 12.7 mm though what am I missing here? Do I really need a punch that big, or will my 17mm drill bit do the job?

Much thanks in advance!
Remi

the barb for the hose fitment is 1/2" or 12.7mm. But you aren't making a hole in the kettle for the barb. You are making a hole for a threaded nipple to pass through the kettle wall and allow for connection of the valve assembly (and a nut on the other side). And that hole size will depend on your valve.

 

[Remos112]

And that hole size will depend on your valve.

that makes perfect sense. My pump has 1/2 male npt threading and I ordered fittings for that, hose barbs and a ball valve. I quite like that size of tubing, so the plan was to order another ball valve with 1/2 female thread. and 1/2 threaded to 1/2 hose barbs. to mount on the kettle. Can I assume that would work? Thanks so far.