Drill & Bulkhead Sizes

VivianViv

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Hi,
I need to drill one of my tanks and install a bulkhead. Haven't decided on the size yet. But I'm confused about sizes, inside/outside diameters, etc.

I am hoping that someone could tell me what size diamond drill bit would need for PVC which they call 3/4", 1 inch and 1.5 inches. Thanks
 

JettsPapa

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Welcome to the forum. I'm on my phone now, but I have a PDF on my desktop with the actual pipe sizes. I'll try to remember to check first thing tomorrow morning and reply back.
 
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VivianViv

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Thank you very much. But I have seen various charts like this and what they don't tell you is what size drill you need for the bulkhead size. Everything is a bit different it seems. Or do you just assume that a 1" drill will be fine for a "1 inch" bulkhead which in turn will take a "1 inch" piece of PVC? They might call them all 1" but is that the inside diamete of the "holes" or the OD of the pipe. Is the bulkhead described as in what size pipe it will take? Because a 1" pvc will not fit in a 1" hole. do you see what I mean?

Thanks
 

Inner10

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For NPT knockouts in electrical conduit it's:

3/4" = 1-1/8"
1" = 1-3/8
1.5" = 2"

But I'm an electrical contractor not a plumber...
 

JettsPapa

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Yes, I know what you mean. Pipe comes in different wall thicknesses, with the outside diameter the same for each size. The most common size is schedule 40, but there's also schedule 10, which has a thinner wall, schedule 80, which has a thicker wall, and several others that are less common.

1" pipe, for example, isn't really 1" diameter. The sizes don't match the outside diameter until you get to the larger sizes, starting around 4" if I remember correctly.
 

kallililly1973

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After seeing your thread I watched an Aquarium Co-Op video but forgot to add the video. Sorry. I believe he mentioned the drill size in his description.
 
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VivianViv

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That is perfect. Thanks. I am going to get the smaller 2 bulkheads, drills and PVC. If it doesn't work out I will switch from fish to earthworms. Thanks

And yes, they are real and they are spectacular. :;bananababy
 

Inner10

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VivianViv said:
Thank you very much. But I have seen various charts like this and what they don't tell you is what size drill you need for the bulkhead size. Everything is a bit different it seems. Or do you just assume that a 1" drill will be fine for a "1 inch" bulkhead which in turn will take a "1 inch" piece of PVC? They might call them all 1" but is that the inside diamete of the "holes" or the OD of the pipe. Is the bulkhead described as in what size pipe it will take? Because a 1" pvc will not fit in a 1" hole. do you see what I mean?

Thanks
Plumbing pipe is a nominal size. A 1" PVC pipe has an OD of 1.315" but the ID varies with the wall thickness of the pipe.

VivianViv said:
That is perfect. Thanks. I am going to get the smaller 2 bulkheads, drills and PVC. If it doesn't work out I will switch from fish to earthworms. Thanks
I'm a little disconnected here, if you can show me how these things actually connect I can probably offer some better answers. Got a pic?
 
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VivianViv

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Sure. Here is a picture of a 1" PVC being inserted half way through a 1" (?) bulkhead. The bulkhead goes into the hole you drill in the tank side at the level you want it to siphon at and is screwed down with the washer and large nut. The pipe is then attached.

I found it. And there is also a difference between sched 40 and 80 in size! And I dont even want to get into
  • Slip x Slip – Requires the use of Slip type plumbing fittings and PVC cement.
  • Thread x Thread – Requires the use of NPT Threaded PVC fittings.
  • Slip x Thread – The in-tank side of the bulkhead will demand the use of PVC Slip type fittings and the exterior will need NPT Threaded PVC fittings.
  • Thread x Slip - The exterior side of the bulkhead will require the use of PVC Slip type fittings and the interior in-tank side will require NPT Threaded PVC fittings.

  1. sing the chart below match up the properly sized bulkhead for your hole. We suggest choosing the largest bulkhead that will fit in the hole in your aquarium.

Bulkhead Size Maximum Hole SizeMinimum Hole SizePVC Plumbing Size
1/2" ABS Bulkhead44mm/1.72"27mm/1.06"½” PVC or ½” NPT Threads
3/4" ABS Bulkhead52mm/2.0434mm/1.33"3/4” PVC or 3/4” NPT Threads
1" ABS Bulkhead68mm/2.67"42mm/1.65"1” PVC or 1” NPT Threads
1 1/4" ABS Bulkhead77mm/3.05"51mm/2.00"1 1/4” PVC or 1 1/4” NPT Threads
1 1/2" ABS Bulkhead86mm/3.38"59mm/2.32"1 1/2” PVC or 1 1/2” NPT Threads
2" ABS Bulkhead98mm/3.85"72mm/2.83"2” PVC or 2” NPT Threads
1/2" Sch 80. Bulkhead51mm/2"32mm/1.25"½” PVC or ½” NPT Threads
3/4" Sch 80. Bulkhead59mm/2.32"41mm/1.61"3/4” PVC or 3/4” NPT Threads
1" Sch 80. Bulkhead 65mm/2.55"48mm/1.88"1” PVC or 1” NPT Threads
1 1/4" Sch 80. Bulkhead83mm/3.28"59mm/2.31"1 1/4” PVC or 1 1/4” NPT Threads
1 1/2" Sch 80. Bulkhead 90mm/3.54"64mm/2.56"1 1/2” PVC or 1 1/2” NPT Threads
2” Sch 80. Bulkhead103mm/4.05"81mm/3.18"2” PVC or 2” NPT Threads

Example: If your hole diameter is 1.75” then you will want to use a ¾” ABS Bulkhead, or you could choose between the ½” and ¾” Schedule 80 Bulkheads.


Thanks for all you help!
 

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JettsPapa

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Below is part of the chart I use. As you can see, and as I explained last night, the sizes are nominal. However, I was way off when I said the nominal sizes match the actual OD starting around 4". Looking further down the chart I see that doesn't happen until 14" pipe.

1585653358757.png
 

saltwater60

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From your chart if you go with a 1” bulk head get a 1 and 3/4” drill bit and one inch pipe. The one inch pipe will slip into the glued fitting.
Does that answer your question?
 

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