Hole drill size...

[BBoley24]

I think I am going to use 1 1/2" return lines on my next tank... how big of a hole do I have to get drilled inorder to fit that sized bulkhead in there?

[swedish steel]

If you go to a site like plumbing supply.com you will see a chart showing the hole size required for the particular bulkhead you will be using. The schedule 80 bulkheads take a larger hole than the schedule 40. hth