Bulkhead hole size tolerance

[DonaldLL]

hello...

I have a tank with holes drilled already. I have 3 holes in the bottom of an external overflow. Each hole is 2.5" in diameter and I am told that this will accommodate a 1.5" SCH 40 bulkhead;
There are also 2 holes drilled into the rear wall; each hole is 1.75" in diameter and I am told that these will accomodate a 1" SCH 40 return.

When I go to BRS for example, the drawings for these bulkheads show hole diameters to be smaller. In the case of the 1.5" bulkhead the hole size shown in the diagram is 2.32" where I have a 2.50" hole already cut.
The hole size for the 1" bulkhead is shown in the diagram as 1.65" where the hole already cut is 1.75".

Are these tolerances acceptable?

Thanks

[jeff@zina.com]

You'll be fine. The BRS holes are bare minimum and tight.

Jeff

[Ron Reefman]

Besides, you'll never find a 2.32" or a 1.65" glass hole saw... OK, maybe not never, but when you find it, it will be very rare! :headwalls:

Jeff is exactly right. :thumbsup:

[bnumair]

there is almost 0.5" oring around the fitting that will cover the extra space and not leak.

[RocketEngineer]

Besides, you'll never find a 2.32" or a 1.65" glass hole saw... OK, maybe not never, but when you find it, it will be very rare! :headwalls:

Jeff is exactly right. :thumbsup:

Actually, a 2.36" is a 60mm and a 1.65" is a 42mm. Both size hole saws are available at Bulk Reef Supply.

http://www.bulkreefsupply.com/store/products/pumps-and-plumbing/plumbing-sumps-drill-bits-overflows-uniseals/diamond-coated-glass-drill-bits/42-mm-diamond-coated-glass-drill-bit.html

http://www.bulkreefsupply.com/store/products/pumps-and-plumbing/plumbing-sumps-drill-bits-overflows-uniseals/diamond-coated-glass-drill-bits/60-mm-diamond-coated-glass-drill-bit.html

Remember, if you see a funky English unit, convert it to metric and it may be a very common size.

I would recommend going to a 45mm for a 1" bulkhead though. That size is a little tight at 42mm.

RocketEngineer

[DonaldLL]

thank you, your help is much appreciated :)

[marinelife]

for a schedule 80 1.5" bulkhead I used a 67mm hole saw when Bulk Reef Recommended a 65mm, I am sorry to say if you used a 65mm the bulkhead would not fit the hole.
the numbers they list are not 100% correct.

[uncleof6]

True, however, the OP is inquiring about ABS bulkheads (referred to as sch 40) an the sizes mentioned by RE, are fine and generally used. When discussing Sch 80 bulkheads, and the variations in diameter, even from manufacturer to manufacturer, and element of complexity is introduced, that does not apply to the vast majority of home aquarists, who using ABS bulkheads, realize that Sch 80 is not needed for these systems at all. Both BRS and glass-holes, provide hole saws that will fit the ABS bulkheads without issues.

I use 45mm for 1" bulkheads, and 62mm for 1.5" bulkheads. I suspect his 2.5" hole is actually 62 mm rather than 63.5mm (2.5") <shrugs> legano, illegano.</shrugs>

[DonaldLL]

uncleof6 you are correct in that i am talking about the ABS (sch40) bulkheads. for the record, the holes i have drilled are actually 2.5" not 62mm.

[uncleof6]

uncleof6 you are correct in that i am talking about the ABS (sch40) bulkheads. for the record, the holes i have drilled are actually 2.5" not 62mm.

Ok, 2.5" is fine for ABS bulkheads in the 1.5" size. The 1.75" holes are fine for ABS bulkheads in the 1" size. :)