John guest bulkhead union

[james37128]

I am trying to figure out what size hole i need to drill for a 1/4 in john guest bulkhead union. I don't have it yet, or it would be simple, it's still in the mail. I want to go get the holecutter/drillbit today and get the holes cut and what i need glued before the bulkhead gets here.

 

[das75]

I use 21/64" for a 1/8-27 NPT tap (that's for 1/4" tubing and the JG knockoff fittings fr HD)

 

[james37128]

I am looking for the hole size for this bulkhead; http://www.h2odistributors.com/pi1208s.asp

 

[therealfatman]

If you are drilling a hole in glass, just drill a hole for a 1/2" or 3/4" bulkhead and insert what ever size bushing into it you need to adapt to the Johnny Quest fitting. The fitting you have ordered is so small the bit needed is not going to be one of the diamond bit sizes normally sold to drill holes in glass tanks for the commonly used bulkheads. The smallest hole typically drilled is 28 mm (1-1/8"), which is for a standard 1/2" bulkhead. If it were I, I would order two normal Johnny Quest 1/4" connectors with a 3/8" or 1/2" male thread on end and use a standard 1/2" bulkhead fitting (28 mm hole) My first suggestion would also work.

If you are working with acrylic I suggest you just wait until the fittings arrive and just use a standard high speed drill bit as the fitting looks small enough to fit in a hole smaller than 3/4" diameter.

 

[james37128]

I plan on using a standard drill bit. I am drilling pvc, noting fancy here.

 

[stugray]

I have some of those BHs.

I just measured one across the threads and it looks to be just a touch over 5/8". I would start with the 5/8" and go from there.

However, be careful with these. They are not really meant to be water tight. They are really meant to just hold a tube as it passes through a panel or side of a box.

I think you can get it to be water-tight you will just need an o-ring and maybe a touch of silicone.



EDIT - SORRY I just looked again at what you have, and mine are 1/8" tubing size. Nevermind.....


Stu

 

[james37128]

Thanks anyways stugray. I know what you mean about the watertight, I was planning an flat o ring on both sides, I will silicone if necessary, but I don't think it will be, worse comes to worse, Ill put in a 1/2 inch bulkhead with MPT and add a 1/2 to 1/4 inch reducer and screw in a JG fitting.