I know we have a lot of folks here who are good at math. There’s a discussion going on over on Pinside about playfield pitch. I suggested pitch should only be measured between the flippers because pitch increases as you go up the playfield. Others are saying your playfied is warped, it should be the same pitch top to bottom.
I’ve seen this on brand new games. Over 1 degree of change going up the playfield. Is this some kind of geometry thing, or is 1 degree an expected amount of sag due to the weight of stuff on the playfield and only four mounting points?
For what it’s worth @phishrace I spent a small amount of time trying to figure out an equation that would tell me how much lower your playfield would have to be at the lowest point of the curve in order to have 1.1 degrees difference at two 6" flat spots about 30" apart and quickly gave up. I’m not sure trigonometry would do it but I think so.
Playfields sag and warp and bend and twist. The wood might not be flat, the mechs might be heavy, there might be too many inserts or too few inserts… or whatever. Pinball isn’t perfect and anyone that expects it to be so is going to have a frustrating existance. I usually measure in a few places and pick whatever seems like the best balance. IME, most games seem to be at least a little steeper in the back and most games have a slight dish towards the middle from the outlane areas. If it’s worse in one direction I’ll make the game very slightly unbalanced at the flippers to make up for it. I don’t usually measure for steepness, I just go up/down until I think it feels “right.”
the pitch should be the same up and down the field. The reality is it rarely is. The center, both top to bottom and left to right, is least supported and will sag.
My brain wants to believe 1degree or so (out of 360) of sag is normal, but that’s not how it measures. Pitch seems to increase evenly as you go up.
One thing I forgot about is many newer games have the leg bolt holes moved so that if you install a game on a level floor with all 4 levelers raised, the factory bubble should be near the middle and you’ll measure roughly 6.5 degrees between the flippers. Very little adjustment needed. Whoever thought of that was a genius. We used to have to extend the back levelers to get started.
By chance, I’m doing a playfield swap on a WWater right now. The old playfield isn’t badly worn, but it does show planking you can feel. 5 ply plywood. New Mirco playfield is 9 ply and rock hard. I’ll do before and after pitch measurements with ramps, upper playfields and boulders removed, so I can measure high on the playfield.
