MM0CUG Anti-Rattle Mast Insert (3D Printed)

My Antenna Mast

Around 2 – 3 years ago, after saving up my pennies, I ordered and had fitted one of the wonderful square section aluminium masts from MM0CUG and I am extremely pleased with it.

MM0CUG Winch Operated Mast

I cannot recommend the masts or the guys that design, build and fit them highly enough!

My mast is a two section aluminum, wall mounted tilt over mast measuring around 10m when fully extended and it has served me well in all the time I’ve had it.

The guys behind CUG Mast Solutions did a fantastic job designing and fitting my antenna mast in what would have been an awkward place for other mast solutions. They were even good enough to accommodate me with a custom top plate for my rotator.

But owing to their design / construction the masts do have one little irritation and that is with how the smaller inner mast section has some movement to it inside of the larger outer mast section.

This is because the inner mast section measures 52mm while the larger outer mast section measures 64mm and so there’s a good 12mm of space between the two mast sections.

I am in no way knocking the masts, they are excellent but the movement and resulting rattling and knocking can be extremely irritating to listen to.

The guys at CUG mast solutions have installed a small bar in their design inside the larger mast section to help minimize this gap and the movement but it still allows for the inner section to rotate and rock about a small amount. But there’s only so much that can be done without risking the inner section getting stuck within the outer section.

For this reason, I decided to see if I could design and build an insert to take up the remaining slack between the two mast sections without the insert leading to the inner section getting jammed while taking up that slack.

Enter Freecad and my 3D Printer

So I got busy in Freecad the other day trying to come up with a design that would take up the slack between the inner and outer mast sections.

This is what I came up with…..

MM0CUG Anti Rattle Mast Insert by M6MDR

It is a two part sleeve / insert which should take up the space between the inner and outer mast walls while leaving around 1mm clearance around the inner mast section allowing for some expansion of the metal so that it doesn’t jam up.

I could have designed it as one complete sleeve however this would mean I have to completely remove my antennas to slide the sleeve over the mast sections and in to position.

It seemed a better idea to design a two part system that could be fitted and then fastened together with zip ties once in position.

The design above is fresh off the Freecad drawing board with the first prototype due to be printed this weekend.

I will update this post again and make the STL file available once I’m happy with the design and fitting. Watch this space!!!

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