I used the old u joint and spline ends and purchased a length of steel tube from online metals and cut it to length. I heated the tube with the torch and put the end fittings in the freezer, then slid the end fittings inside the tube and welded all around. They are a tight fit. I did not do any design calculations for this; use at your own risk.
edit:
Simplified back of envelop,
J = 0.0559 in4, Zp = J/r = 0.11183 in3, ty =.577 x 60000 = 34620, Max Torque = ty x Zp =
322 lb-ft for a 1" .095 wall A513 type 5 DOM tube (60ksi)
Say the rope force is 5000 lb at 8 inches radius, the drum torque required is 3333 lb-ft. I have seen pto winch ratings 3000-4000 lbs.
The worm wheel has a 33 tooth count so torque ratio is 33:1, input shaft torque required is 3333/33 = about 100 lb-ft.
Depending on the roll pin installed, this seems to be plenty, even considering the x2 safety factor for winch components.
Somebody check this, I have not done ME stuff for a while, no guarantee this is correct.