Delrin bushing

[Bill Shields]

If it is contained it will be ok ..but I would worry about I coming loose.
All things considered...what is wrong with brass or bronze?
Nylatron would be good.

It will have a shoulder on it do it won't drop.
It might be easier to find brass pipe close to the right size.
McMaster has MDS-filled nylon in tubes that are pretty close to size.

Steve

MDS filled nylon = nylatron by another 'non trade' name...

glass filled teflon? stiffens it up, and considering the amount of rotating it will (not) do in a lifetime, I would not worry about the abrasiveness of the fiberglass...

if PVC and sunlight a concern - paint it....after all. how many hours is is going to actually spend in the sun in the next 20 years?

[curtis cutter]

So the sequence is tower, mast, rotor and finally antenna?

[Bill Shields]

ISN'T THIS just one of those 'crank up antennas' on wheels hopefully do not need to be climbed once erected?

Kinda like what are called COWs (Cell on Wheels) that are used for emergencies

[ernest_t]

I will suggest polyurethane. It's tough and withstands being out in the weather.

[ChipMaker4130]

How many do you need?

[SteveM]

ISN'T THIS just one of those 'crank up antennas' on wheels hopefully do not need to be climbed once erected?

Kinda like what are called COWs (Cell on Wheels) that are used for emergencies

Yes, they are 50' free-standing antenna towers. They have large outriggers that stabilize them.

Steve

[Bill Shields]

so...how long did the original bushing made from whatever it was -> last?

I've got all kinds of plastic and bronze laying around. happy to make you something and send it your way.

just need a decent drawing...with usable tolerances

[SteveM]

so...how long did the original bushing made from whatever it was -> last?

It doesn't have one. The hole is just larger than the mast we are using.

That's probably good anyway, as I think both the mast and the tube are aluminum, which is pretty much the worst combination of shaft and bearing.

I've got all kinds of plastic and bronze laying around. happy to make you something and send it your way.
just need a decent drawing...with usable tolerances

Won't have all the dimensions until they get me a piece of mast.

Not sure how precision the tube on the tower is. I might want to make it here just so that I can adjust as needed.

If you'd have a piece of material for me, that would be appreciated.

I think bronze will be overkill, so a suitable plastic would do it.

Steve

[Bill Shields]

need an idea on length and OD.

easier for me to get it close to OD and length and put a rough hole in the center and cut it off....and mail the semi-finished ring....

[SteveM]

Got a hold of some 6-1/4" x 12-1/4" slugs of acetal.

IMG_20230321_140741.jpg (387.48 KiB) Viewed 1159 times

We machined bushings out of them, and had enough left over to make spacers, as parts of the rotor were going to hit the tower braces.

IMG_20230401_173953.jpg (249.88 KiB) Viewed 1159 times

IMG_20230401_174415.jpg (200.15 KiB) Viewed 1159 times

As the antennas will likely see fewer than 100 full rotations a year and at slow speed, these will probably last decades.
Steve

[Bill Shields]

[Mr Ron]

so...how long did the original bushing made from whatever it was -> last?

It doesn't have one. The hole is just larger than the mast we are using.

That's probably good anyway, as I think both the mast and the tube are aluminum, which is pretty much the worst combination of shaft and bearing.

I've got all kinds of plastic and bronze laying around. happy to make you something and send it your way.
just need a decent drawing...with usable tolerances

Won't have all the dimensions until they get me a piece of mast.

Not sure how precision the tube on the tower is. I might want to make it here just so that I can adjust as needed.

If you'd have a piece of material for me, that would be appreciated.

I think bronze will be overkill, so a suitable plastic would do it.

Steve

I would not consider it overkill. Your reputation is built upon good work and materials. My choice would be naval bronze.