just for starters, make sure your tractor has the stones for loader operation..a lot of the frames need additional bracing to handle loader stress..a good idea is to run length wise tubing from the front to back to spread the weight stresses out along the frame and transaxle..since you did say it was a Simplicity that you are using, it might be do-able, the 71 series were some pretty stout tractors in the day. Vertical loader mast posts might be 2x4 tubing with 3/16"wall..I'd run my loader arm hinge pin all the way across the machine uprights,maybe use 1" 4140 steel to hinge/support the loader arms..I've had good success with arms made from 1/2"steel plate. 2"bore cylinders are more than enough to lift anything you'll need to be doing with this size tractor. I've used used salvage cylinders in the past,only to have them blow out after using them for a few months..my advice buy your cylinders from Surplus Center,you have a reasonable chance at them lasting a while then..PITA to take apart a newly fabbed machine only to make repairs,I could write a white paper on that itself...you'll get help here at MBN thats for sure..lots of loaders built here.
