Calculate spindle speed using absolute pitch!

Note: if you hate math, skip this post.

This is how I looked during a 12+ minute cycle on the mill:

long cycle cnc boredom

So, what better way to entertain myself than to guess the spindle speed based on the MERRRRRP pitch??

You can play along too!

Here’s what I had to work with:

1110 rpm 2

Mary Jane is working on the mill in a factory. She hears an E pitch three octaves below concert pitch A. Knowing that the pitch is created by a tool spinning at a certain speed, and knowing that concert pitch A is 440Hz, how fast is the tool spinning in rpm (rotations per minute)?

Easy peasy! But I have not taken a math class since senior year of high school, over 10 years ago. Granted, the last math class I took was multivariable calculus… so I have a decently developed conceptual grasp of math, but I’m very horribly out of practice. When you’re done solving the problem, scroll down to see how my poor brain stumbled through.

1110 rpm 3

1110 rpm 5

1110 rpm 4

Only 9 rpm off! Enough to break a tap, sure, but still! That might have been the most gratifying use of absolute pitch in the history of MJ.


Goodbye, factory!

Goodbye, factory! I’ll miss everyone there very much.

I’m shifting my evening focus to violin making (and hopefully not failing to meet my posting schedule here any more).

Now let’s revisit the very beginning of my little CNC adventure.

coolant is gross and splattery

Check out my awesome view!!!!

view through cnc door

And let’s wrap up with some excessively smiley factory selfies! 😀 😀 😀 😀

cnc happy

I had a good time.

My factory job

CNC is a delicate subject in the violin making world. I work in a factory operating CNC machinery, but please, chill out! This is all I do there:


cnc operation


See? That is not a violin.

In fact, I don’t even really know what it is….


Note: I may or may not have drawn this at work while waiting for a long cycle to finish. 😛