Lawrence,
I think from what you have described so far leads me to be looking at 2 locations where the contamination of the metal is originating from possibly either 2 sources or just one... Process of elimination will determine if both locations or only originating from one source of the contamination - yad-yad-yada!
The two I'm guessing are #1.) the air from the compressor tank especially if the air is as you previously mentioned being "Wet" due to a variety of possibilities which I will come back to later with detailed questions pertaining to the compressor tank...
#2.) The other possible source may be the residual oil from the shear especially if the faces of each cut member make up both members of the root face, but at this point I would like to come back to source possibility #1. and ask the questions pertaining to the compressor,,,
First off, are you using air as part of either a mixed gas used for PAC? Because if so, there is a possibility that even if there is only a slight, or small amount of water in the tank, and the tank isn't drained daily from wherever the drain valve or plug is located which is usually the bottom of the tank... I have also seen the drain valve, or plug located to the side of the tank and above the tank bottom sometimes when I would go service a truckload of Linde, and Thermal Arc, or Hypertherm and the early Miller models of air supplied plasma cutters at the many customers back in the day when I used to service them many moons ago... Good call Kent.
Those drain valve or plug locations gave me a quick reason to doubt whoever was maintaining these systems if they were doing so properly... Duhhh??? And needless to say, a quick change of the location for the drain valve or plug to it's proper location in order to perform an also proper draining of the compressor, resulted in solving the problem of contamination along with having an in line air and oil filter located close to where the output line connected to the PAC... In other words don't just look at the obvious when diagnosing these sort of problems even though most of the time they may just be staring you in the face...
Okay, let's focus on the other possible source which is residual oil from the shear.
You wrote this: "Root faces freshly sheared, they are on a conveyor literally 20' from the workstation :( " And then Gerald posted this: "Have you tried removing the scale from or cleaning the
root face and not just the
bevel face ?" Here is where I think that Gerald is on to something because if the root faces aren't at least checked for any residual contamination like the oil you mentioned previously that you discovered in an earlier post by posting this:
"The Bar line (shear tool) does leave a drop of oil from time to time on the stock, but that is easy to see. The drops are not getting on the cut areas.
The blade has some oil/grease on it, but I'm not seeing residue on the cut surfaces. This does raise the question; should shear blades be oil free? I don't know. I was hesitant to ask them to degrease it." they do usually have a little but not so much that would lead to possible contamination if the sheared faces are cleaned afterwards with a quick wipe or degreasing of some sort to make sure...
Well I looked at the 2 posts where you mention the shear blades some oil/grease on it, and then in another post before that one regarding the root faces being freshly sheared... It kinda makes me wonder about what you're describing so if you can clarify this in order to avoid any possible confusion it would be most appreciated... Now this nothing more than conjecture at the present so one needs to eliminate any and all of the possibilities as the source of contamination and these 2 locations are good place IMHO to start.
P.S. So at this point, are they grinding the faces clean or are they backgouging instead until you solve the problem?
Respectfully,
Henry