"Know Your Coils" is a 30 page booklet written by myself (Mark Sender) in 2017.
It is aimed at tattooers who wish to know and understand their coil machines better.
It has a bunch of helpful sections which include;
-Understanding your Machine
-Diagnosing a problem
-Running in your new machine
The book is printed in small format (A6) so it can easily be kept in your toolbox or station for quick referencing on the job.
There are also some notes pages in the back where you can document your observations.
Give it a read, it may answer some lingering questions or cement your knowledge about tattoo machines.