I like the system used on the W3JK antenna I'm building right now. It
uses hex head machine screws with nylock nuts (UV-proof). The hole in
one side of the outer section is drilled larger, so the screw head
clears. The screw sizes go from 10-24 for the 1.25 tubing to 8-32 for
the smaller ones. I'm going one step further, and putting blue Loctite
on all the screws. Needless to say, the screws and nuts must be stainless.
That said, when I refurbished my A3 a while ago, I put sheet metal
screws in all the joints, in addition to the clamps. I used number 6
screws, which seemed adequate. One could always put two of them in the
larger sections.
73,
Scott K9MA
On 5/8/2019 20:08, Garry via TowerTalk wrote:
Greetings all,
I am rebuilding a 17 meter beam I built about 35 years ago. At the time I used slots and
hose clamps where fastening element sections together but this time I am going to use
sheet metal screws. My tubing sizes will taper from 1.125" down to .625" in 5
sections per side.
I can't find any information on what size screws to use unless I'm just looking
over it. I have seen a recommendation to use hex head screws rather than typical
flat blade or phillips head due to possible damage to the screw head but nothing on
screw size. I also wonder if self tapping would be a better option than standard
sheet metal type.
Any thoughts will be most appreciated.
Thanks & 73,Garry - K4OR
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Scott K9MA
k9ma@sdellington.us
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