You are on the right track. The second rotator plate should have a
plate with a hole just oversize for the mast. Then as the crane lowers
the mast into the tower it will keep the mast near vertical. You really
don't want or need a second thrust bearing, just the saddle clamp
against the plate will hold the mast to take out the rotator.
The tricky part is to figure out how to lift the mast off the rotator
for service at a later time. You can see how it goes together the first
time - loosen the saddle clamp and lower the mast load onto the
rotator. With the crane doing the lift it is one thing. When there is
no crane and the mast/stack needs lifting, using a pry bar against the
tower or rotator to lift the bottom of the mast is a bad idea. A block
and tackle in the confined space at the top of the tower has much better
control, is safer, and works for one person. I drilled my tower top
plate for a galvanized forged eyebolt (double jam nuts) and had a second
saddle with an attachment point (two short metal straps onto the u-bolt
ends) bolted above the temporary load bearing saddle. A 500# rated
block and tackle (look at 4 part blocks at West Marine with snap
shackles and a jam cleat and low stretch line) allowed me to raise the
mast/stack the few inches to get the rotator out for servicing. Space
everything so the bottom of the mast is ALWAYS restrained by the second
rotator plate.
Grant
Mark Robinson wrote:
> snip
>
> I am thinking of setting a second bearing plate just above the rotor which
> will be about 4 feet below the top thrust bearing. I will have a TB3 bearing
> on it. I may well lift this bearing off the plate and clamp it to the mast a
> few inches above the plate so that I don't have alignment issues. The
> bearing just sits in the air above the plate. When I want to remove the
> rotor I should be able to lower the bearing, bolt it to the plate and add a
> clamp to the mast so that the mast rests on this bearing or will the bearing
> stop the mast sliding down. Some sort of u
> bolt or a saddle clamp should work.
snip
>
>
>
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