Weston Thermometer

[Jerry Bodine]

Then you obviously need a third watch!

And simply average them, or get several and develop an algorithm for a programmable HP calculator (they run on RPN - Reverse Polish Notation? Just kidding, of course.

[Robert Bowring]

I have used a Weston adjustable dial thermometer for a long time and find it to be very reliable. I check it regularly against my Unicolor Precision mercury thermometer and adjust it if necessary. Works very well.

[Richard Wasserman]

If you use the same thermometer all the time and adjust your process accordingly, I don't see why the thermometer needs to be perfectly accurate, close enough seems OK to me, as long as it reads the same all the time. I'm thinking B&W

[Harold_4074]

About three years ago, I bought a new Weston thermometer to replace the little 1" dial thermometer that I had always used. It was a while (months) before I put it to use, and discovered that while it was quite accurate (against a Kodak Process Thermometer) it would sometimes stick. Tapping the face would give a true reading, so I considered the merits of returning it. But then I realized that I sort of instinctively tap any dial-type gauge (pressure, temperature, voltage...) so maybe knowing that I have to tap it is better than getting a "good" one and just assuming that I won't.

Incidentally, one of the better arguments for electronic thermometers is that slightly bending the step will not change the calibration. This happened to my old thermometer, and the low reading (about 1-1/2 scale divisions) was enough to ruin some pictures until I figured it out...

Whatever style one uses, having a liquid-in-glass thermometer readable to a degree (F) or less and reserved as a reference is a very, very good idea---both electronic and mechanical thermometers can go bad slowly.