I have a 14" dymax tree shear called the ranch ax and it is a 1600# beast. I think it is the cadillac of skid steer tree shears. A friend of mine has part time business and has tried different companies, and Dymax makes in the best in his opinion. Couldn't hurt this thing. I push and pile trees with it, grab cut down trees and move them etc. Two, 8" cylinders with 3" rams. Will cut a 14" cedar but not 14" hardwood. Will cut about 11-12" hardwood. I run this on a Bobcat S300 which has about 19 gpm flow and 3300 psi and I wish the flow rate was even higher for more optimum capacity. I sheared about 400 trees last weekend in about 7 hours. All different sizes from 1" to more than I could chew off. Only got stuck once.
I made a spray kit for mine to spray the stumps of hardwoods with Pathway after cutting to stop regrowth. Push button in cab to run electric pump that sprays the stump.
What kind of trees and diameter are you considering? What is the lift capacity of the FEL? What is your hydraulic flow rate or psi? For the small size of tractor, you maybe limited to 4-5" diameter trees at the ground level. Tree shears take a lot of abuse and tremendous force on the shears and equipment. I am afraid your
B1700 won't be able to lift one built heavy enough for anything much bigger. If you build one, be sure to make a brush guard on the unit to protect the grill/tractor.
My brother is a state forester and they made a tractor FEL prototype many years ago. It seemed very well built with 6" farm implement type cylinders, 6"x6" base frame, 4x4" brush guard and they still had mulitiple instances of breaking the frame or cylinder attachment with the 2500 psi of farm tractors.
I wouldn't be concerned about overheating the hydraulics. The hydraulics don't run all the time and the actual heavy use of the cylinder if relatively breif. You will need valve controls to lift the FEL, tip/curl the shear and another control to open and close the shear hydraulic. 3 valves needed. You could use just one hydraulic cylinder on a moveable shear which would cut against a fixed shear. This will imensely help your cycle times on opening and closing the shear. However, one cylinder put more stress on the loader because it will frequently push the front of the loader and tractor to one side as the cylinder closes.
It maybe much easier to rent a small to mid sized skid steer and shear for limited use. A skid steer can do a lot of trees in a day. You don't need a big skid steer for shearing. Smaller sizes actually are preferred and with tracks, they can go most places.
