Is there any practical way to exactly center a 1 1/2 mast inside an YAESU
GS-065 thrust bearing while we are unconfortable installing the mast on top
of the tower (65 feet high...)?
The mast is 1 1/2" (OD is 1.89"), 13 feet long and is pretty straigh. The
rotor is a HAM-M inside the tower, 6.0 feet below the top plate, which is a
flat 3/16" steel plate.
I've done some tests on the ground and found that any minor error adjusting
the retaining bolts of the GS-065 causes the mast to turn eccentrically,
severely forcing the rotor and the thrust bearing.
Precisely adjusting the retaining bolts has been difficult because:
- there are two sets of them;
- the GS-065 has an internal diameter of 2.75" and the mast here is OD
1.89" - a big difference in diameters;
- the adjustment must provide good alignment both on the vertical and
I think that I will not be able to make a good centering while I am at the
top of the tower without some kind of tool like a bushing for filling the
empty space between the mast and the bearing.
Such a bushing should have to fill all the space (from the top to the
bottom of the bearing), in order to avoid misalignements both on the
horizontal plane as well as on the vertical plane. Besides, the bushing
should have to be sliced in four pieces, to avoid the retaining bolts...
I took the measures with a caliper rule, made a sketch and ordered the
bushing from a lathe shop... it came pretty well done... but, to my
surprise, when I forced down the slices into the clear slots (between mast
and bearing, between the bolts), they only penetrated half an inch! Then I
discovered that the GS-065 inside cilindrical surface is irregular. Its
internal diameter VARIES and has some other irregularities.
Now what? I've never read anything on this subject, so your advice will be
very wellcome. To see pictures of the bearing, top plate and bushing,
please go to http://igspot.ig.com.br/rmurad/new-tower.html