I realize many of my posts have been somewhat… negative lately… in analyzing, remembering, and describing the current state of women in engineering. To balance it out, I thought I’d throw in a more uplifting type anecdote. So, this is the story of how I was taught by a male supervisor to stop making a fool of myself in the machine shop – and its all about leverage!

I worked in the college machine shop during the first couple of years of my engineering education. It was fun and engineeringly-cool, though I didn’t feel completely comfortable holding my own in any around the shop banter and definitely wasn’t one of the guys. Compounded by my own self-consciousness and lack of confidence in my abilities in the shop, there were a few tasks that I specifically dreaded because I didn’t know how to do them with my body.

For instance – have you ever used a milling machine? It was one of my favorite things in the shop, super viscerally satisfying, awesomely powerful yet requiring a delicate and careful touch (like all machining, really). Yet for all that I enjoyed using the milling machine to make parts, I dreaded working on it because there was one step of the break-down process I wasn’t strong enough to do…I thought.

To remove a collet that’s installed in a decent-sized mill, you have to loosen the hex drawbar nut that is at the very tip top of the machine (~70″ from the ground or higher) while simultaneously applying a brake to the spindle at the same height so that the nut you’re trying to loosen doesn’t just spin freely with the assembly. Suffice it to say, you have to do this:

At the end of each work or class session when it was time to pack and clean up, I would literally hang from the brake lever, swatting at the wrench attached to the drawbar, praying somehow to generate enough torque to loosen the damn nut. It usually took more than a few tries, the entire time me thinking “I hope no one’s watching, I hope no one’s watching, I look so weak and buffonish….”and furtively checking after each try to play it cool and make sure no one saw me flailing away at this wrench and brake above my head.

I was too proud to ask for help – none of the guys needed help! At that point, I was trying really hard to fit in and not call any extra attention to myself, plus I had a lot of misplaced pride and thought that doing stuff alone without help would make me me tougher and more “respectable”. I had seen my fellow student workers them do it and knew they could without any problems, so I assumed that I should be able to as well despite being a foot shorter and at least 50 pounds lighter then them.

Eventually, thankfully, my shop supervisor noticed my tarzan moves and taught me an amazing lesson in leverage. He brought over a stepstool, told me to stand on it and give that nut one more try now that my arms were in line with the center of my body instead of fully extended over my head. Simple, right? But SO effective. By pulling my arms into the same plane as my torso, I was able to use the strength of my entire chest, core, shoulders and arms (as opposed to just my arms) to hold the brake and loosen the nut. And it didn’t require him doing it for me – just handing me a tool to even out the mechanical advantage. He knew I was physically strong enough to do it, but just didn’t understand how to position myself in the situation.

I had never previously noticed that there were stepstools in the shop since I hadn’t ever seen anyone use them before. (And I was ashamed/scared/too stupid to look for one or think about using one?) But, come to think of it, they had mentioned something in the machining textbook about positioning yourself in the same plane with respect to the object of your work.

~~~  a brief side note and at home demo ~~~

In addition to being a female engineer, I am also a yoga instructor. As so much of yoga speaks to me biomechanically as proofs of leverage and force balances, this whole problem with the mill strikes me as also telling of how unconnected and ignorant of my own body I was back then.

One of the fundamental principles of yoga (and physics, statics, and dynamics as it turns out) is that hugging to the midline or bringing items in from the periphery makes you more stable and gives you more power. You can easily do a little experiment to verify this:

And its also an excellent illustration of forces, moment arms and torque! Remember that torque (τ) is the (cross) product of a force (F) and its moment arm (r). Let’s draw some free body diagrams to analyze further….

So  – to recap – my reasons for not knowing how to loosen the nut from the spindle were:

1) I was too lame to ask for help.
2) I didn’t know how to use my body to maximize my leverage and strength
3) I didn’t know how to apply the physics and math principles in my own body.

And, thankfully, the shop guy handed me a stepstool and told me to get on it. An elegant solution, to be sure, that taught me much more than just how to remove a collet from a mill. =)