Frankc: I just took my Woods 7500 and subframe off of my
B7800 to do some 3ph work. Will be glad to take and post some pics w/in the next couple of days.
I can tell you this, having just taken it off; it is made out of VERY solid chanel bars and weighs a pile. The front end pins into a matching mount under the front center of the tractor frame just behind the front wheels. The rear then has an assembly with two slots that slip over the pins for the lower arms of the 3ph. Those pins then tie with two pins on the subframe just behind the slots. A heavy duty toplink then ties the BH itself to the toplink mount.
The whole thing makes for a VERY solid mount attaching the subframe to the tractor frame at 3 points plus the toplink. The subframe channel members look strong enough so that they take all the lifting and twisting forces generated when using the BH. If I understand the physics correctly, both the subframe and the tractor's main frame are both resisting those forces.
I assume that you're comfortable with heavy duty welding. I sure wouldn't want to tackle making one of these unless I was. Even with that, you will need to fabricate the front and rear mounting assemblies with a great deal of precision; they both fit very precisely with their mating assemblies on the tractor, with a minimum of play. So much so that the main skills in removing and mounting the BH and subframe are (1) backing the tractor up to the subframe perfectly centered and in line with its exact direction and (2) learning to use the BH boom and stabilizer hydraulics to line up the rear slots EXACTLY with the pins so that you can then back the tractor 3ph pins into the slots. If you are just a bit off, the pins will not both slide all the way to the rear of the subframe slots and unless they do, you can't lock them with the pins on the subframe.
Hope this doesn't sound too daunting. The subframe actually isn't difficult to mount and remove, once you get the hang of it, but if the subframe assemblies don't exactly mate with the tractor, it ain't gonna work.
