If I may without stealing anyones thunder I did roughly the same but on a lathe a while ago
Started off with this lot from the local metal suppliers / fabricators.
The rotor in the barrow made from a propane bottle wasn't part of it. that's what it has to lift. My problem is this part of the shop is a low wooden building with a flat roof and only simple wooden rafter that can't support anything. The rear wall is just a dividing wall made from block and the end return is just that, a brick free standing pillar so there is no support from the building at all.
So first off turn a pin up out of the 3 1/2" round solid bar.

The two lands are the right size to go inside the long steel box section, the flats are clearance for the internal weld in the tube, Push into position and the two lands line up with 8 5/8" pre drilled holes and these are plug welded to hold the pin in place.

Then the upright has a floor plate welded on it and secured to the floor, this is more to stop it sliding under load as all the weight is taken downwards. A series of brackets are then welded on to fasten to the end of the lathe by four M12 HT bolts.
This is what is supporting the load when lifting.

The jib is the other piece of 3/8" wall box with a bush welded on the pivot end with nylon bushes. I like nylon for this as it's very forgiving and a natural brake to stop it swinging under load. Winch is the typical £50 Aldi special on some saddle brackets.

Quick road test with the rotor and it good, testing was done using the MK l strain gauge, I put my fingers above the jig and felt the clearance between the roof and the jib, when the load went it this dipped about 10mm which in my book is a pass.
Then to do the overload test as all lifting gear has to lift more than it's needed to so on the assumption you can't get two rotors in the lathe at once this is the test


Again a 10mm drop, in fact no matter what i do i only get this 10mm drop which I put down to play in the nylon bushes.
Last mod was to fit an old spare rack that was kicking about to give easy of movement along the jib, plus a stop on the end.

Just timed it right as 3 days later according to the date stamp on the pictures this little bugger rolled up.

And fitted in the chuck - just, tailstock was on it's limit.

Been an absolute godsend when you are working on your own as I am.