Sunday, June 27, 2021

Mount design is whupping my a**

In previous posts I've discussed trying to come up with a more rigid alternative strut mount -- one that does not rely on the RAM mount balls. This is because the RAM ball mounts can and do "slip" under load. They are good and useful and I plan to keep them as an option, but I'd like a more rigid alternative.

The design process has been truly a horror. Most difficult has been the angular adjustment. Making it out of 3D printed material is surprisingly hard, especially since the PETG I'm using these days has a really low friction coefficient, so any sort of frictional clamping, for example, the design below, seems doomed to failure:

Undaunted, I came up with a design that used a lot of interesting parts from McMaster, including a rod end bolt (, binding barrels (, and leveling washers ( All told, this came to a hardware BOM only of about $75 per unit. Eek! This is what it looked like, just so you can behold it and then move on:

So then I decided to improvise with standard machine screws and washers and what not, to make the equivalent mechanism using "hardware store" parts. This was a mitigated success. This is what the design looks like:

This is what it looks like on the inside:

But now the problem is finding a way to clamp the tube into the forward area without crushing the plastic and without creating sharp protrusions that will cut into the bungee cords that hold the whole thing together. This is what the latest prototype looks like:

And just in case you're wondering, here's my scrap pile:

Wish me luck! :)

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