I don't recall if this is who I bought them from but they look just like this and I paid about the same price. I often forget I even have them but when I do use them they have yet to let me down. The thickest I have done is 10ga plate
pretty sure a bunch of us lncluding me, got light racing ones from sexton offroad a long time ago. Used them a bunch no problems. I also recall someone on here machining some locally
I also got mine from summit machine. The bigger ones are good quality and have been used a bunch with almost no signs of wear. The little ones though weren't done very good though and don't dimple like the ones I once borrowed. I bet I got a better deal on them then chocflip201.
Crosbike on here made me a set from some cold rolled bar that have held up great. I find my self useing 3/4 the most. I have pressed 3/16 several times with no problems of any signs of wear.
I'm with Kiel, Light Racing sourced from Sexton. I use the smaller sizes more than the larger ones, just because they fit on smaller parts. The big ones sure are cool when you can justify them though.