Some of the best Mechanical PE Reference Books

 Mechanical PE exam strategies eBook

Advice, Tips and Tricks, and Strategies to help you pass the mechanical PE exam the first time

The Mechanical PE Exam Strategies book is a result of my endless searches for exam preparation. It contains all the tactics I used to pass the exam and some great information to help you makes things go smoothly. It will help you in every stage of preparation for the PE exam. Application, studying + preparing, taking the test, and post test/ongoing maintenance of your registration.
Marks' Standard Handbook for Mechanical Engineers

Marks' Standard Handbook for Mechanical Engineers

Some people prefer the presentation of information in Marks’ compared to the MERM. The amount of information in this book is equally as diverse as the MERM. This book contains a few pieces of information that aren’t in the MERM as well. Various beam loading contitions, quick reference tables for section properties, and some good information on bolts/connectors are good examples of this. I used this book during the PE exam and it came in handy during a couple problems.
 ASHRAE Fundamentals Handbook

ASHRAE Fundamentals Handbook

This book is pretty much a must have if you're taking the HVAC afternoon section. This will go into much more depth than the MERM or Marks' do for HVAC. During my exam I only referenced this book about two times (I took the Machine Design afternoon section) but it will come in handy if you're not too strong in HVAC. The books comes in two different versions (one in Metric units and the other in US Customary units).
MERM Mechanical Engineering Reference Manual Michael Lindburgh

Mechanical Engineering Reference Manual (MERM)

This is considered "the bible" for the Mechanical PE exam, and for good reason. This book was my main reference on the exam. It contains a treasure trove of information which you can apply on the exam. You'll need to get used to the layout and presentation of the material, but I highly recommend this book. Also, you'll need to reinforce the book binding (it is notoriously weak). Consider this book an investment, you'll be able to use it throughout your career.
 ASME Steam Tables Compact Edition

ASME Steam Tables-Compact Edition

This book just gives you information on steam tables. There is another book published by ASME which is a bit more comprehensive when it comes to all things related to steam, but this book should have everything you'll need. The steam tables in this book will have more information than the ones in the MERM so it will help save you some time interpolating numbers. Relatively cheap price for a handy reference book.
 Machinery's Handbook

Machinery's Handbook

This is another handy reference book. While this book is small in size (~5"x7"), it has about 2700 pages. This thing is packed with pretty much any information you would want or need to know in regards to Machine Design. Not only will this book be valuable during the exam, you'll be able to use it your entire career. If you don't already own this book I highly recommend you invest in it
 NFPA 90A

NFPA 90A

This book is recommended for the afternoon HVAC section. It will contain some good standards which could help you out on this section of the exam.