Hinged telescopic aluminium mast
I decided to make a telescopic mast from 100 x 100 x 3 mm and 80 x 80 x 3mm aluminium square tubing. Each section being 5m long. From the bottom of the tower runs a steel cable to the top, to the inside of the big tube and to the bottom of the thin tube where a pulley is mounted. Around that pulley and up again to the top of the big tube were the steel cable is fixed. If you pull at the bottom end of the steel cable the tower will go up.
On the next photo you see the top end of the big tube were another pulley is mounted.
This is the other end of the big tube. Here the steel cable is attached. Make sure not to have sharp bends.
The gap between the 2 tubes is about 14mm. I used 5mm nylon plate to fill that gap.
As 5mm nylon was not enough to fill the gap, some epoxy PCB was used to fill the gap.
Make sure that you have a gap in the nylon to run the steel cable through.
A complete view of the bigger tube. Note the 2 gaps for the steel cable. The pulley has to be mounted in a way that the steel cable will move easily in the tube.
In the thin tube you have to cut some slots for the steel cable.
Here you see the pulley mounted in bottom end of the thinner tube. It runs in 2 pieces of nylon. The thickness of the nylon has to fill the gap between the 2 tubes (2 x 7 mm in my case). The nylon bushings keeps the tube in place.
The 2 tubes mounted.
About one meter from the bottom of the thin tube I mounted some nylon. It is the end stop so you cannot pull the tubes apart. Note I forgot to cut slots for the steel cable. You have to drill and tap because there is no way you can use nuts and bolts here.
Below you see the 2 tubes with the steel cable fitted. To get the steel cable in was the biggest problem.
The steel cable is fixed around some 30mm thick aluminium stock to prevent sharp bends.
I wanted to fit a round pipe on top for mounting rotators and antennas on. With the help I got some nice nylon blocks machined for this.
The winch mounted.
The round tube is fixed with a 10mm bolt and some nylon bushings. The bottom end is mounted in the same way to prevent that the tubes slide completely into each other.
Some cable guide was bent from aluminium 20 x 2 mm strip.
The hexbeam mounted on the tilted tower.
Top wall bracket with pulley to pull the mast up.
The bottom hinge for tilting the mast.
The hexbeam is up in the morning light.
