Best way to use a forge + pyrometer for heat treat

[NittanyRider]

Do any of you use a pyrometer and thermocouple inside a gas forge for heat treat?  If so, how do you know when the blade has reached the correct temp?  One thread I found on another site suggested to place the thermocouple inside the forge, adjust burner as needed to get to desired temp, then place blade in forge and wait till blade is the same color as the inside of the forge.  This approach still seems a bit subjective (basing it on color) and assumes that the temp is constant everywhere inside the forge (which I know is not the case).

Any info on this would be greatly appreciated.

David

[NittanyRider]

After I posted this I found two TG threads with the info I was looking for (thanks Doug!).  If you are interested:

  Heat treat setup  

   Installing high temp thermometer in forge

[kbaknife]

None of this stuff is easy.
Outside of using a controlled electric oven, or a PID controlled forge, there comes lots of time spent in front of the forge and heat treating experience.
Knowing what your steel is doing and what condition it is in at what temp/color, etc., comes with spending hours in the shop.
You will hurt nothing by pulling your knife OUT of the forge.
You can ruin it by leaving it IN the forge too long.
Run your forge as low and steady as it will go, yet still be up in the austenizing range.
As it brightens up, pull it out frequently checking it with a handy magnet. Notice the color of the steel as it reaches non-magnetic. This is only 1418 degress - you still need to go to the NEXT bright color range for most of the shallow hardening steels.
I use a probe and display mostly to just get the forge running slowly and consistently.
I use magnetism, color and time control for knowing when to quench - in the correct quenchant.
None of this comes overnight.

[NittanyRider]

Thanks, Karl, I appreciate the information.  I'm using 1084 from Aldo.  I also have a 2.5" SS pipe that I'll use as an "oven" within the forge.  Good advice to not focus on just the numbers on the pyrometer display... rather use it as a guide. So far, I've heat treated two  blades using color and a magnet.  The process seemed to work, but I'd like it to not be so much of a guessing game.  

I'll keep at it!