You’re in the kitchen taking notes while staring at a pot with 5 (FIVE) thermometers in it as it heats up to, and cools down from a boil… ;D
Pick one and go with it, brew good beer. If it’s off it’s off, if it brews good beer! A man with five thermometers simply don’t know what temperature it is! 
Agreed in principle… however… 1 dial is in the HLT, one dial is in the MLT…one dial in the BK, who cares except for the below 80º part. The kitchen one is to stave off salmonella, the glass is a “control”
The frustrating part is that the divergences are not linear…
Glass/MLT/BK/HLT/KIT
211/212/213/210/212
186/188/190/184/183
177/177/179/170/180
170/168/169/166/164
160/158/160/156/160
150/146/147/144/144
146/140/139/138/142
Lol! I know what you mean. I have ten! The Miljoco’s are great, the Loves are also. I try to keep them all under control with my Thermapen. I have one moving probe during brew day. It is one of my Love controllers. All brew day temps are based on that one probe, right or wrong. It makes great beer!
Brew on brotha…
Yeah, I’ve done the five (or six) thermometer test before. Drove me nuts. That experiment immediately preceded my purchase of the thermapen.
Damn, I knew pilots depended on redundancies but that is re-donk-ulous. 
By the way, how many hydrometers do you have? Reminded me of our last brew session. .004 difference between
the two we had…
:-[
The thermapen is counted as one of my most valued belongings.
After doing the same thing Oscar has just done and losing digitals into the mash I settled on a couple cheap agreeing dial thermometers. Haven’t done the callibrate to 154F thing yet but everything lines up at boiling & freezing. The thermapen has the final say on everything.
;D
Last brew day my dial thermometers were all reading different, and none of them were matching the digital.
I finally realized you could turn the nut on stem to adjust them.
Doh! :-[
…you open a brewery (FTW) 
One. Once it’s done, it’s done. Whether the beer is 5.2% or 5.4% I don’t care, I’m going to drink it.
Aside from that I know it reads .002 low at 60º and I am assuming that the error is linear. I may be .0005 of at some point, but in that case see my first statement.
Only one hydrometer? Allow me to let you in on a little known secret: glass doesn’t bounce!
If it’s made of glass, whatever it is, I have two (or more).
For the record, I have five hydrometers (not to mention a refractometer). Two bottling version (0.990-1.020), and three regular. I had four but broke one. I did not set out to have that many, but two were gifted to me when someone cleaned up an estate. They were made by a glass company in Cincinnati that hasn’t existed for years.
You guys are funny. It’s like putting a tachometer and an altimeter on your trail bike.
You’re right, I should get a second one for a spare…but they’ll be DIFFERENT, and then the whole insanity will start over again…stop the voices, stop the voices… ;D
Thermapen schmermapen. Here’s what you REALLY need: http://www.diytrade.com/china/4/products/3198797/Infrared_thermometer.html
+/- 2.7*F. Eh…
It’s really not that bad. See, once you have a second one, you’ll never break the first one so you don’t care if they match. If you only have one, though, that’s when you’ll break it.
Thermapen ordered.
…you spend a couple of hours every day on homebrew forums. :
By the way, I broke down and ordered a Thermapen.
You won’t regret that decision.