I was going to measure our leagues Diamond tables last week to compare to mine at home but forgot to bring my gauge. Will try and remember tomorrow night. If you are referencing my two gauges you are right, they are somewhat cheap, but both read the exact same on a sample 45 deg cut I made on a piece of wood in my shop, and my Starrett read exactly 45 deg on that also. So could all 4 things be off, possibly, but I doubt enough to matter. What could be off is how you measure or how carefully you hold the protractor. That could possibly be off 1/2-1 deg depending on how you measure or how sloppy you are, but not 2 or 3 deg.
I am not going to buy an expensive angle gauge just to prove a point when my two protractors and my Starrett tool all measure exactly the same on a test 45 deg cut made in my shop. By the way, I don't consider a Starrett a toy.
I'm still looking for an answer as to how to measure for 141 deg? Is it following the front rail nose then up the top edge of the rail angle, or is it the rail nose and straight back the pocket angle? There is a difference of about a deg with the top edge being the higher deg.
Really not doubting you RC, I'm just curious in knowing as my table plays different, rattles balls more, than all other Diamond tables I have played on and actually play on every week. Even friends of ours that play on ours, and the ones in our league say my table is challenging in comparison, and yet I have the 4 3/4" pockets. I wish we had got the 4 1/2" ones.
What is tough is trying to get a picture of the protractor when it's parallel to the nose, ie down apx 3/16" in the back.
I'll try to remember tomorrow.