In alt.home.repair, on Sun, 04 Feb 2018 11:51:08 -0500,
"(PeteCresswell)" wrote:

I've been trying to buy four refrigerator/freezer thermometers and it's
frustrating how inaccurate/inconsistent they are.

For Instance:

- 4 thermometers of same make/model, hanging on the same rack.

- Alcohol bulb/glass tube - you'd think basic physics...

That only works if the bulb is exactly the right size and the amount of
alcohol or mercury inside is exactly correct. I don't want to spend
too much just to get accuracy that won't really help me.

- Each reads a different temp from 68 to 74 degrees.

Last time I bought a thermometer, about 40 years ago (not counting a
digital one that claims to measure humidity), a glass one, there were
about 8 on the rack and I looked at each temp and bought one whose
reading was part of the cluster of readings very close to each other.

What more could I do.

Only thing I can think of is that the card behind the glass thingie is
misaligned, but looking at these things, there does not seem to be enough
physical room for those kinds of errors.

I don't think the card is the problem. Glass thermometers sometimes or
always have a scratch, a file mark, at 32 degrees, on one side of the
tube, I've read. I've never looked closely and I've never seen the
mark, but it makes sense (and it contradicts my first paragraph above,
come to think of it). They'd put all the thermometers in a mixture of
melting ice and water, maybe even in a refrigerated room. Pull them out
one at a time and file the scratch wherever the level happens to be.

Also, at home I have a couple of digital indoor/outdoor thermometers.

Bring the outdoor sensor inside and put it right next to the master part, and
they're a couple degrees different.

Is there any hope at all of finding four thermometers which:

- All read the same temp when placed side-by-side
- Read the correct temp.

What am I missing?

Cynicism. Hopelessness.