Category Archives: Mechanical

Button Box for Christmas

Button Box

My wife had asked me to build a board or box with a bunch of levers, locks, handles, and doors for my two boys. I’ve always thought that it was a good idea, I’m just not that interested in things completely mechanical. So, I decided to build a button box that did essentially what my wife wanted while also being engaging enough for me to work on.

I did some quick google searches for such boxes, and found two. I was pretty shocked that I only found two, but I did find a lot of people who wanted to build this. It turns out that most people either didn’t have the time or the task became too overwhelming. Fortunately, I’m all about simplicity and I had a hard deadline!

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CAD is Perfect… but it’s not Engineering!


Have you ever had a mechanical designer say to you “I don’t understand why it doesn’t work… the CAD looks right!?” I have! And it raises an interesting point that is repeatedly ignored. CAD is an amazing tool that can help you predict how a product will turn out… but it doesn’t replace REAL ENGINEERING!

Just to put it into perspective, a coworker of mine came up to me and asked me who ‘The Engineer’ was on a particular project we both were working on… I said, “I am”. Then she said, “No no – The Engineer… The ElectricalEngineer” as if it were a higher calling! Let me think… I designed the hardware, circuit, and wrote the program… but because I’m a ‘mechanical ‘guy’ I wasn’t considered the engineer. Needless to say, that really stuck with me. It brought back all of those late nights of studying and working my way through my degree only to get disregarded by a high school drop out. We design real things… and this has two drawbacks. Continue reading

Auto-Clutch Concept 1-1

This clutch is designed to engage and disengage a motor from a shaft (not shown). The triangular lobes are attached to the outer ring through a living hinge. As the outer ring is driven by a belt, the lobes flex toward and lock onto the shaft. The idea behind it works, but unfortunately it doesn’t for my application. The shaft also translates and this clutch requires ‘grounding’. I use the term grounding to refer to the physical attachment of the inner ring, not an electrical characteristic.

3D Printing & it’s Achilles Heels – Part 2

Design Applications


CAD is a very powerful tool. You can design a football stadium… and you can design microfluidic channels. Unfortunately it’s very easy to lose your ‘frame of scale’. In other words, you don’t know how big… or small something is in real life. 3D Printing allows you to get a feel for the actual part in a way that you could never accomplish through a computer screen alone.

This works especially well for industrial designers. Their concern is how something looks, feels, and the overall experience of the device. CAD can try to fake reality by adding perspective, but it isn’t the real thing. When it comes right down to it, you need to have it in your hands. Not only that, once you print something out, you can modify it. You can sand, cut, machine, paint, melt, bend, etc… Whatever modifications you can think of to get it the way you want it. And then you can update CAD, reprint, etc…


3D Printing & it’s Achilles Heels – Part 1

FDM 3D Printing is a common way to prototype. It’s quick, clean, and gets parts in your hands in a matter of hours… but what can you really do with it?

In the following series of posts, I will discuss the different design elements that go into using 3D printed parts for prototype development. Here is what will be included:

  1. Design Applications
  2. Material Types… Especially for ESD Compliance
  3. The Printing Process & its Achilles Heels
  4. Printing Large Parts
  5. Designing for Machined Post Operations
  6. Getting Holes Right
  7. Modifying Parts to Increase Strength
  8. Part Identification

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