Hello again,  I was at the Harbor Freight store yesterday and looked
at the digital calipers again.  They have 4", 6", 8", and 12" versions.
At the moment, the 6" ones are on sale for $15.99 and the 12" ones
are $34.99.  The 4" version is regular price of $24.99 and the 8" is
$44.99.  When I got my 8" calipers they were half price (as was the
4" one).  The special sales change every few weeks so you can just wait
for them.

By the way, I have looked at the other makes and they _look_ identical
(who knows) but the prices are much higher.  The ones Enco and MCS sell
are about $36 but they are plastic, whereas the Harbor Freight ones are
stainless steel.  Enco and MCS sell stainless versions for about $60.
(MCS and Enco have very similar web sites; are they connected?)

The nice thing about a digital caliper is that you can use it for
adding and subtracting.  If you want to measure the depth of a hole,
for instance, you can put a block across the hole and set the caliper
to the thickness of the block.  Then press zero and measure the hole.
The reading will be the difference between the thickness of the block
and the total height, which is the depth of the hole.  I've found this
to be very handy.

As I mentioned before, I intend to get a couple of calipers to use as
digital readouts for my mill and lathe.

Regards
Craig Smith
Upstate New York, near Rochester - below zero for the first time today.