On 2011-11-29, P E Schoen wrote:
"Winston" wrote in message ...

[big snip...]

For your 'fixed' installations, you could solder
some small 'earphone' wire to the battery contacts
and use a huge, cheap external cell. (Huge = AA)

I didn't expect my post to generate such a big discussion, but it's been
quite interesting. Since I only use my calipers once in a while (it had been
years until I once again tried to use them and found out how to fix them),
it seems that just removing the cell is best, and that guards against
possible damage if it leaks. My machine shop is in an unheated building and
the temperature and humidity extremes may make leakage more likely.

FWIW -- this discussion has prompted me to check out the B&S
Digital calipers which I have (two, only one of which I have run on
batteries, because the proper batteries went to unobtanium before I got
the second one (for free) -- each in its own fitted wooden box. The
first cost me $15.00 at a hamfest.

The original batteries were the 625 Mercury cells -- weird
format and of course a lower voltage than most others -- 1.35 V when
new.

The caliper has a glass optical scale down the groove where the
depth gauge lives and the rack gear is on a dial caliper, so it is one w
which I trust to be accurate.

It used four of those cells. I figured that if the electronics
and LEDs (used to illuminate the glass scale) could tolerate 6 V instead
of the 5.4 V with the original cells, I could likely use a pair of CR 2032
3V cells. Well ... a bit of work on the electronics bench shows that it
will indeed tolerate the higher voltage. It also draws 1.4 mA instead
of the 40 uA range that the newer calipers use) so I really plan to add
a switch to the battery holder.

I think that all I need to do is remove some of the jumper
strips which went between cells, and make a new screw-on cover for the
new cells to hold them in proper alignment.

If so -- it will add two extra calipers to my collection.

Enjoy,
DoN.

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