I have a bunch of 2" filters, and some adapters that they should thread into. For the most part, they suck, and only screw on 1/2 turn before binding. I tested all the parts I have, and came up with the following summary table.
Is it just me, or are these M48x0.75 threads really finicky to machine and are therefore not very cross-compatible? Kind of surprising, they are not that complex, and I have some reputable brands in the mix.