Swing is cable with a couple wraps around the brake drum then goes thru pulleys hooked to the ends of 2 single acting cylinders that lay down facing the front ( engine end) and hooked to a 2 two-way valve. I'll get some pix of that part ---- its a nightmare lookin setup but will come almost all the way around on the swing cycle, then you go back the other way, same distance.
Most of my diggins are a 90 degree swing , but it will go further when needed.
I copied the swing idea from a Bucyrus Erie 6 ton truck crane.
Dad also had an old Hopto pto drive backhoe that was cable / cylinder swing. They were set up this same way---- my way of doing the idea was real crude but works great and swings fast!--- kinda makes ya dizzy after a while runnin it LOL!

"A machine you build yourself is a vote for a different way of life. There are things you have to earn with your hands."