WAYNE M - Ahhhh 17-4 machnes HARD even when it isn't welded! I used to play with Stainless in the shop, still have MANY drill bits with BLUE ends on them because of it! I used to buy TONS of 15-5 forged blocks for the co I worked for 20 yrs ago. It machined kinda hard too.
ALSO, I used to work at International's FARMALL Plant in Rock Island, IL, where they built most of their BIG ag tractors, 70-200 HP. They used a lot of Cub Cadets to do ground maintenance, mowing, plowing snow, hauling huge trash carts made from 4' x 8' sheets of steel set on four small caster wheels, they were heavy empty and when loaded to over-flowing with busted up cardboard boxes & coffee cups, they were really heavy, now tie 2-3 loaded ones together.
I talked to the maintenance manager about those CC's and he said they used to use GD Cubbies and had some clutch issues from all the starting & stopping, but once they started using Hydro's they never really had much of any problem with them. So yes, the Hydro's are TOUGH!