There are several factors to consider with the hole size needed for a bulkhead. The information below is considered "general" guidelines for the most popular types of bulkheads. (For example they may not apply to schedule 80 bulkheads).
|Bulkhead Size||Recommended Hole Sizes|
|3/4 inch||1 1/2 inches||35 to 40 mm|
|3/4 inch thick wall||1 3/4 inches||45 mm|
|1 inch||1 3/4 inches||45 mm|
|1 1/2 inch||2 1/2 inches||60 to 65 mm|
Be sure to check with your supplier before ordering, and be sure to have bulkheads in hand before having a tank custom drilled!!
|3/4 inch bulkhead||1.0 inch bulkhead||1 1/2 inch bulkhead|