any tips welcome
Overall, pretty solid mechanics. You seem comfortable the way you throw. It looks pretty good overall.
It seems like you have late acceleration in your delivery, instead of attacking from the first move. If you wanted to try to squeak out a few more mph, I might suggest:
-get the front hip more forward at the top of your lift for more and earlier momentum down the mound which will give you the ability to more quickly drive off the back leg. Driving from a higher position may give you more length in the stride, which tends to add 1-2 mph by itself.
-reduce that back leg collapse during the stride. You won’t need it if you get faster earlier in the delivery. Speed and power applied early in the delivery definitely add 2-5 mph by the time you get to release. The collapse is a mechanism many pitchers add compensate for a slower start to their delivery.
-the tempo during the lift and through hand break and back knee collapse seems a bit slow to yield a max velocity result
Of course you can always disagree, it’s just what I see.