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Fjr of Mobile, AL, wanted to build a trebuchet. He soon discovered that it was a huge hassle because the parts he could find weren’t compatible with each other.

I was talking to my brother and as I talked I was frustrated at how hard it was to build things. The biggest problem in my opinion is, everytime I want to build something, it pretty much always involves some kind of shafts.

Shafts have several functions:
1. They hold components where they need to be. But they also need to be held in place on the shaft.
2. Shafts give various components a common rotational axis.
3. Shafts transmit motion from one component to another.

If you want to place a component on a shaft and have it perform reliably, it needs to be held in place on the shaft. If you want a component to spin smoothly, then you need a bearing placed on your shaft. The bearing needs to have the same inner diameter as the shaft’s outer diameter, within a few thousandths, if not things will vibrate and wobble and all kinds of problems. Most shafts get stacked on with a different diameter for each component. Thats alot of custom machining.

I don’t have the resources to machine custom shafts each time I have an idea, and I’m not alone in not having them.

What’s needed is a standard, a system.

Fjr created a number of possible parts to his “Simplified Mechanical System,” including the two above. What do you think, readers? Do we need a series of standard components for maker projects? Leave a comment.