[Towertalk] Mast Coupler

[Dennis Mowers]

Thanks everyone, for the many suggestions.

I visited the BMW dealer, and had no trouble finding the part.  

When I mentioned flex disk, the parts man said "what size".  He said
they come in small, med, and large.  He than walked about 5 ft, pulled
out a couple of drawers, and brought a 4 inch disk, and a 7 inch disk
for my inspection.

I selected the small one.  The price was $63 with tax.  A little more
than the $25 mentioned in the by Leeson.

The actual size is 4.25 in X 1 inch thick, with 6, 1/16 inch wall
inserts for 3/8 inch bolts.  Stamped with the BMW logo, which probably
added $30 to the price.

A couple of weeks ago, I spent a few hours looking for off the shelf
couplers.

Most of the flexible couplers I found by searching the internet are made
for marine applications, and expensive.

I spent a lot of time looking at couplers in the McMaster-Carr and
Graniger catalogs.  There are several types available that might do the
job and the ones for 2 inch shafts were also a little pricey.  You need
to buy 3 pieces.  Two, 2 inch shaft couplers, and a rubber insert.  As I
recall, Boston Gear has a nice one that would be about $150 for each
coupler, and $40 for the insert.

So, I saved a little money, and have the joy of trying something new,
and making my own part.  The part will be a lot easier to make than the
custom top plate and rotor shelf I just made, for the non Rohn tower I'm
using.

Now that I have the BMW part number, I will look for a cheaper
substitute for the next one I need.

73, Dennis