Better than Google
When I started my first full-time engineering job out of college, my first of many company-appointed mentors was a guy named Cam. I’d come to find that these mentoring relationships were like arranged marriages that were often short-lived and awkward. This one, however, was pretty great. Cam was a mid-career engineer and a PhD student who showed me around, and we had a ton of laughs in the process. When I completed my master’s degree in 2009, Cam bought me my first copy of Machinery’s Handbook. It was the prevailing opinion of the old timers in the cubicle farm that any mechanical engineer worth their salt (what does that even mean?) had a copy on their desk.
Been there 14 years.
Dr. Massey, if you ever read this, shoot me a note and I’ll buy you a beer. Honestly, that’ll probably work for just about anyone.
Although we didn’t keep in touch and only worked together directly for the first six months or so, Cam’s biggest (and continued) impact on me was this book. Over the years, I’ve taken to purchasing it whenever I see a used copy floating around at yard sales, antique stores, or on auction sites where I’m usually looking for old tools. I’ve given away about a dozen of them to different engineers who I’ve worked with in my career, hoping that they’ll enjoy it nearly as much as I have. It’s likely that many of them never open it at all, preferring to stick to Google searches, but in accordance with my grumpy-old-man-despite-not-yet-being-that-old demeanor, I’ll stick with the book.
Every year, my copy gets more bookmarks, post-it notes, and highlights as I spend more time with it. I hope to continue to put it through the paces for years to come.
My copy.
Post-it from the last person who borrowed this off my desk.
If you’re interested in picking up a copy, do yourself a favor and avoid buying a brand new one. The information within isn’t changing drastically, and I usually pay around $10 for them instead of the cover price, which is north of $100.
I wouldn’t say that the Machinery’s Handbook is the last or only word in any design, but I’ve been using it as a quick reference when I’m trying to put together a rough idea before spending hours digging through specs or completing analyses to validate some of my choices. Sometimes, there are too many options for each of too many decisions and no prior art available to you, and you just need to get started.
I went through my copy to find the 5 sections I’ve used most often, and I thought I’d share them here. I’ve probably touched less than 5% of what is available in these pages. I hope you buy someone this book or loan them your copy and design something awesome together. Maybe they’ll buy you a beer in return.
Fasteners: Whenever I am designing something that doesn’t have great access for tools, or for some other reason gets me away from the usual suspects with fastener choices, I can pop open the handbook and get a quick overview of what’s available and a refresher on the correct search terms if I’m looking for a source online. Not just the names of different types of heads, but also what size hex head goes with a given bolt diameter, or what hex key would work with a socket head cap screw of a given size. Bonus: you can also see guidelines on tool clearances for things like socket wrenches, box end wrenches, standard counterbore diameters, etc.
Side Note: Everything looks bigger when you zoom in on the CAD tube. More times than I can recall in my career, I’ve picked up my phone to a technician telling me something I designed “can’t be built”. It’s worth the extra time in your design phase to model a wrench and ensure you can get enough rotation to flip it over and keep going rather than find out they’re right and have a whole production schedule stop and wait for you to figure it out. It’s also nice to have a good machine shop close by (or an angle grinder) if you need to make or modify your own tool because you got a little sporty.Thread forms: I’ve yet to see a fastener spec that gives the full dimensions of the male and female threads for performing analyses like thread shear area calculations. It’s great to have the tables giving you all of the dimensions and tolerances of Unified Screw Threads. There are also diagrams and definitions, in case you’re like me and tend to forget which diameter nomenclature refers to which feature.
Moments of Inertia: Yes, we learned how to calculate this in school. Yes, I can probably struggle through most of them, or squint and make everything a combination of circles and rectangles and get close enough. But for common cross sections, they list out the formulas for moments of inertia so you don’t have to go through it. It’s nice.
Beam Stress and Deflection Tables: Again, I can draw a free body diagram, and I look back fondly on Professor Safadi’s Strength of Materials and Statics classes, but there are better uses of my time than deriving formulae for slightly different loading conditions when these are here.
Machining and Manufacturing sections: Most of us end up in a job or organization that uses a small quantity of processes over and over again. Then one day you realize you’re planning to machine a part out of billet that should be sheet metal, and you have to get smart on a process you haven’t really ever designed for in a hurry. These sections give the basics for getting started. I’m a big fan of calling the people that will be making your parts and talking through things, but before I do that on a process I’m not super familiar with, I’ll skim the section to get the jargon and rules of thumb fresh in my mind, allowing me to cut some of the translation loss that’s bound to happen.
