Replacement Masthead Rotator adaptor

Mike asked me to make a stronger rotator attachment plate for his telescopic mast. The top section is thick walled GRP with 40mm OD. I made a collar and a central pin to fit inside the tube, and fitted the usual 12mm plate with 119mm PCD 8.4mm holes to fit Yaesu or Kenpro rotators. The collar was put in the freezer and the plate in the oven, then they were aligned and pressed swiftly into position to make a string shrink fitted join.

The completed assembly was fixed in place with gap-filling Loctite.

The completed assembly with original guy ring and stub mast and the internal (invisible) pin
All the things….
Rotator plate top side
Rotator plate underside
Collar and rotator-plate mount. The raised section is 0.03mm oversize for a shrink/press fit
Underside of the collar
HDPE bearing bush with guy plate in place
Stub mast inserted and top half of guy ring bearing fitted
Top side of the collar before drilling the centre hole
Underside of the assembly with guy ring HDPE bearings and retaining ring and centre hole
Complete assembly showing (L-R) stub mast, retaining ring, lower HDPE bearing, Guy ring, upper HDPE bearing, collar and rotator plate
Reinforcing pin to fit inside the GRP mast
Pin in the test stub mast which Mike helpfully sawed off for me to use as a template
Underside with the pin bolted through the rotator plate
The mount in place on top of Mike’;s mast with his Kenpro rotator.

Leave a Reply

Your email address will not be published.