Capacitance Touch Sensing on Large Metal Object

So I am using the Capacitance Sensing Library (found here: https://playground.arduino.cc/Main/CapacitiveSensor?from=Main.CapSense) and I need to measure/detect when absolute touch is made on fairly large piece of metal, a bandsaw blade. I have had success with detecting touch on the blade and also seeing reaction from a distance away, I am using a variable resistor box so I can change the resistance on the fly for testing. I have tested all the way from about 500k ohm to 22M ohm and have been able to detect changes in touch/distance from sensor okay. The problem is, it is not very consistent and I only to detect absolute touch, skin to metal contact. Even day to day the values I read seem to change from the sensor, so I am using a code to average the values received to make a new trigger point when it starts up. It works fairly well on the small blades, but the problem lies with a light touch, just barely touching the metal but still touching. No matter the resistor size I choose a light touch makes almost no noticeable difference! Am I measuring wrong, is the Arduino not sensitive enough? At this point I just need suggestions for detecting absolute touch no matter how little on a piece of metal with an Arduino. Thanks for any ideas!

I suggest research on variables that may effect the sensing. Room temperature, room humidity, time of day. Are you the only one touching? Are you wearing the same clothes, shoes, just washed hands, morning shower?

You can't very well solve a problem without knowing what may cause the problem.

Paul