A friend in France asked me to make a Rexolite 1422 lens to fit in a 21mm ID brass tube
My friend in the Netherlands needed some custom clamps to fit the splitters to his big EME array
Mike asked me to make up a Rexolite copy of the HB9PZK feedhorn lens for 10GHz in 22mm copper pipe.
Nice simple turning job using 1 inch stock.
A friend in the Netherlands asked me to make a few bits for his new giant 144MHz EME array
I seem to be making a fair few of these. Much the same as the others, but here’s a bit of turning action
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.
A friend asked me to reproduce a missing element of a commercial UHF LPDA. The thread was #8-32 UNF and trying to find suitable slotted pan-head stainless screws was a nightmare, so I had to use a Philips head instead.
A local friend asked me to make up a joining spigot to fix two 40mm Delrin tubes together. Nice simple job. I made it a very tight hammer-in fit and knurled part of the 20mm sections to help prevent any rotation or creep.
A friend asked if I could machine the ends of a soft copper tube around 70mm diameter to be flat and square, and to an exact length. Not easy to hold in the lathe, so I made up some expanding mandrels from engineering plastic.
I made a silver steel shaft with an M12 threads on one end and drilled a centre. The other end mounts in a 12mm ER40 collet and there is a bracing tube so tightening the nut forces the the tapered plugs into the split mandrels and they open and press very tightly against the inside of the copper tube. The mandrels when uncompressed are a tight fit in the tube.
Using this technique allows full access to both ends and the whole outside of the tube for machining and polishing.
The simple approach to attach an Octagon LNB to a circular waveguide is to saw off the ridged scalar horn and push the cut end into a split 22mm pipe, but I decided to do it the long way. I made up a conical plug from brass to fit against the cone of the horn, then bored a tapered hole inside the plug to match the 17.5mm ID of the Octagon to the 20.2mm ID of 22mm water pipe waveguide. Probably totally unnecessary, but I had fun doing it.
First step was a CAD design