Air compressor side plug. Tap for air supply?

[Hugemoose]

This is a stock photo off of google, but for reference sake, I have a similar type plug on my 30 gallon, vertical Eastwood compressor. (However the nut size is quite larger.) Photo below

I would like to drill and tap this for a 1/2" black iron pipe line to feed a regulator/air separator which would then supply the rest of my garage.

Right now it's just a small 1/4 pipe to the pressure switch and regulator. I'm trying to get the most out of this little compressor with high flow fittings everywhere I can, and just a 3/8" 50' hose after a small run of the pipe to where I have the spool. This seems like a good restriction to me.

And idea on what tap would work best for this? All I currently have is a cheap Advance Auto kit for smaller size stuff that I use on cars.

 

[gungatim]

you would need a NPT pipe thread tap.

usually you would just unscrew the plug that is in there and buy a reducer fitting instead of going to the trouble of drilling and tapping, but they can be stuck in there pretty good.

 

[Hugemoose]

you would need a NPT pipe thread tap.

usually you would just unscrew the plug that is in there and buy a reducer fitting instead of going to the trouble of drilling and tapping, but they can be stuck in there pretty good.

I'm all for buying a reducer fitting if they exist. But in my brief internet searching I haven't found anything obvious that would work.

And I've already pulled the plug once when I bought it (only 2 months ago). It's in good shape and easy to get out.

 

[redmondjp]

You would use a 1/2" NPTF pipe thread tap.

The other option would be to go a bit smaller than 1/2", but up to a 3/8" NPT pipe size instead.

EDIT (seeing new posts above): This is a no-brainer - they make pipe reducer fittings so forget about tapping anything, just remove that plug and reduce down to either 1/2" or 3/8" NPTF.

 

[ChaseDE]

Yeah you want whatever that tap is x 1/2" hex bushing, like this.

2" x 1/2" hex bushing

https://www.supplyhouse.com/Everflow-BMBU2002-2-x-1-2-Black-Hex-Bushing

 

[Hugemoose]

Yeah you want whatever that tap is x 1/2" hex bushing, like this.

2" x 1/2" hex bushing

https://www.supplyhouse.com/Everflow-BMBU2002-2-x-1-2-Black-Hex-Bushing

That's what I had in mind! I'll take some measurements tonight, as I'm not 100% sure it is 2", but it appears that there are a few options there and I can find something to work. Thank you!

 

[kjbenner]

I'm all for buying a reducer fitting if they exist. But in my brief internet searching I haven't found anything obvious that would work.

And I've already pulled the plug once when I bought it (only 2 months ago). It's in good shape and easy to get out.

A reducing bushing is what you're looking for. Should only be a couple of bucks--cheaper than a tap and drill and you'll still have your old plug if you want to go back. You'll have to figure out what size the tapped hole you have is (http://machiningproducts.com/html/NPT-Thread-Dimensions.html). You might have to use 2 bushings if you're trying to drop several sizes.

 

[thooks]

You're probably not going to find that bushing at HD. You will either need to use two bushings or go to a real plumbing supply house.

Also, NEVER do what you talked about to an ASME Code pressure vessel (cutting/threading/tapping/etc)....

The correct way to do what you want is to weld a weld-o-let on, but that should be done by someone that is either certified to work on pressure vessels or has the knowledge, experience and skills to do such.

 

[thooks]

Here's another idea- Put a tee/****** in the plugged hole. Plug one side of the tee and use the other side for your intended purpose. Something else you could do is install a separate pressure gauge. Just a thought.

 

[rpcraft]

reduce your reducer--- They have bell reducers and you can use insert reducers to get it down to the size you need without it sticking out too much but you will probably still need at least a few inches to get it reduced down but your last reducer could be an elbow reducer to help direct it towards the direction you need it most, if you have cramped space.

 

[turbowoodworker]

I did this with my Husky years ago. HD had all the bell reducers you could need. Way less trouble than what you are proposing.

 

[Hugemoose]

Thanks for the help guys. I'll go grab the bell reducers required and get this done the right way. I'm a chemist by trade, and get my hands dirty playing with cars, so plumbing code and proper procedure are still a little new to me.