Does any one have a combination square and digital caliper from Freight Harbor?
Are they any good? I know Starret is better but I just need some reasonably
tool(not a pain in the neck) for my projects.
Are you talking about a single tool which serves both purposes,
or two separate ones?
I guess that it you mean the latter, just putting them in the
opposite order "Digital caliper and combination square" would eliminate
the confusion as to how far the "combination" applies.
I don't know the Harbor Freight tools from experience, though
here are the things which I would consider important:
1) Combination square:
a) Are the numbers and lines engraved, or simply stamped
into the scale? If the latter, the accuracy is a lot
b) How accurate are the angular relationships between
the scale and the heads? Check the 90 degree parts
against a rigid machinists square. Check both the
head alone against the machinists square on a surface
plate, and the head and rule against the machinists
square separately. Also -- check the 90 degree and
45 degree points on the protractor head against the
appropriate surfaces of the square head.
c) How smoothly does the scale slide in the heads, and
how firm a grip does the lock achieve?
d) Is the scale straight, or does it have a curve?
e) What is the material of the heads? Steel or cast
iron are good ones. Aluminum is not likely to retain
its accuracy. The rule should be hardened, ground,
f) For a used one -- check that you don't have a "shrink
rule" calibrated for something like making patterns
for casting metal, where there is expected to be a
certain amount of shrinkage, so the rule causes you
to make the patterns oversized by the proper amount.
2) Digital caliper:
a) How smooth is the travel of the head?
b) Is there a thumb roller to allow fine adjustment?
c) How common a style of battery does it use?
d) Are there provisions for turning it *fully* off?
Some turn the display off automatically after a few
minutes of inactivity. On these, when you move the
head, does the display turn back on with the proper
Ones which can be turned fully off give better
battery life, if you are not using them every day.
My older Starrett does not turn fully off, and to get
good battery life, I have to slide the battery holder
on the back just far enough to disconnect the
batteries, and to re-zero it when I turn it back on.
The Mitutoyo, in contrast, goes into "sleep" mode
with no easy way to turn it fully off, but gives
pretty good battery life (much better than the
Starrett without the sliding battery holder trick,
but not as good as with). However, the Mitutoyo
wakes up in proper calibration whenever and wherever
it is turned on -- unless the batteries have died or
been replaced since the last time it was turned on.
Then, you have to re-zero it.
Cheap digital calipers (e.g. the $8.95 one form a
hamfest which a friend got) tend to really eat
e) What is the material? Mitutoyo makes both stainless
steel bodied ones which are quite accurate, and
inexpensive ones with a fiberglass filled plastic
body (light green, IIRC), which is less likely to be
accurate over time.
f) What about absolute accuracy? The specs on some of
the inexpensive ones may be 0.0005" resolution (the
smallest change which can be measured), but only
0.005" (ten times worse) accuracy when you check all
points along the length with gauge blocks. (Others
turn out better than expected -- but you can't tell
with the cheap ones.)
But -- the absolute accuracy may not matter that
much, unless you are very careful how you use it,
because closing the tips of the jaws on a workpiece
can cause enough tilting of the head so the reading
can be several thousandths off (more likely in the
longer ones like 12" length with longer jaws).
So -- for serious measurements, you will want a set
of micrometers (0.0001" vernier scale and carbide
anvils) to cover the range of workpiece sizes likely
in your lathe. I've got them from 0-12" for my 12"
swing Clausing, but in reality 0-8" is probably more
reasonable to cover just what will swing over the
carriage -- unless you are making precise things
which are too large to fit over the carriage -- as
perhaps a flywheel whose surface is also expected to
precisely drive a flat belt.
Digital calipers normally have a resolution of
0.0005", but can hardly be depended upon to provide
that accuracy in general use. (Good ones, perhaps,
used very carefully may approach that, but not in
Regular micrometers have the barrels calibrated in
0.001" steps (except metric ones, of course). Better
ones add a vernier scale to take the resolution down
to 0.0001". Digital ones will take it a bit past
that, with a resolution of 0.00005". However,
careless use will still not get accuracy even as good
as the first style. You need to ideally learn the
proper "feel" (how tight to tighten the micrometer
onto the workpiece). Better micrometers will have
either a ratchet thimble (the small "tit" on the end
of the spindle will click and not turn the thimble at
a certain torque), or a "friction thimble", in which
the whole knurled grip on the thimble will slip to
limit torque. Note that there is always a way to set
it or to grip it to exceed those settings. The
friction thimble (in good condition) can probably be
the best choice for an inexperienced user. The click
limit is not quite as precise. But the best it to
develop your own "feel" (grip it just tight enough so
the thimble slips under your fingers before you get
to the point at which the friction thimble or the
ratchet thimble releases. And set the zero of the
micrometer using the same feel.
Note that the reading which you will get on some
surfaces (e.g. a grooved one from the wrong feed rate
or a poorly sharpened lathe tool) will vary widely
between the methods, because you are getting enough
force from the screws to crush the ridges, thus
changing the readings.
And the anvils of the micrometer should be cleaned
whenever you zero it (or check the zero), and
whenever you read using it. Tiny particles of grit
can shift your readings significantly. Standard
practice is to lightly close the anvils of the
micrometer (or the jaws of the calipers) onto a piece
of clean paper, and slowly withdraw it from between
the jaws without opening them. This tends to carry
out any grit which may be present.
All of this being said -- you can start out with the cheap ones,
and plan to get better as you learn. This way, if you damage something
you won't feel as bad if you damage an $8.00 digital caliper as you
would with a $200.00 digital caliper by one of the big makers. I still
keep a 0-4" Helios dial caliper which has a serious ding in the ID
measuring surfaces on the jaws because it got too close to a rotating
chuck on a Unimat lathe. I would much rather that had happened to an
$8.00 one (if such were available back then.)
If the cheap tools survive, you can use them as the ones to lend
to someone who wants to borrow your tools. Keep the good ones out of
For anything digital, keep a full spare set of batteries in the
case with it. The batteries *will* fail at the most inconvenient time.
And I keep at least one vernier caliper for use if all of my
digital tools decide to die on the same day. It stays beside my
computer for the infrequent use that it would get up here, where the
batteries are more likely to die between uses.
The most frequent failures of the batteries are in my older 12"
Mitutoyo digital calipers -- simply because I don't *need* that size
I hope that this is some help -- in spite of it not dealing
with the explicit products which you asked about.
I picked up one of the 6" digital units on sale and it was definitely
worth it at half price! Actually I WAS suprised by it's quasi-quality
and it serves its purpose well of something more accurate than my tape
measure.. that's all. Just open it up before you buy it and make sure
it isn't busted. Buy your squares from Lowes or HomeDepot.
Good site. I tend to buy the silver oxide 357s for some
calipers (the Starrett takes a larger "coin" battery), micrometers, and
the HP 15C and 16C calculators, so I buy a dozen at a time, along with
some other orders from MSC.
And if you want to extend the storage life of batteries not yet
in equipment, store them in the 'fridge (for most, not in the freezer,
just normal cooling a bit above freezing).
Wow, a hearty "thank you" for that; I've been wondered why my caliper
batteries bonk out at me so fast, and now I know why. I'm gonna go spend
the $2.79 at Batteries Plus to get the one I need today (need one anyway).
The 6" digital calipers are a great deal at the usual $20 sale price
and an even better deal at the recent $15 sale price.
The combination square is of poor quality IMO. You may not be happy
with this one.
Maxell or Sony silver oxide SR44W - $.97 + $1.89 sh. Free shipping for
5 or more. I bought 5 and was dismayed when they came and they appeared
to be no-name. But it was just the package, the battery itself was
I have been pleased with my cheapy HF digital caliper. That said, I
wouldn't buy a combination square from them.
As you know, Starret has always been the big name at the higher end,
although Mitutoyo and Brown&Sharpe also make very high quality
squares. Another name to look for, and what I bought for our lab, is
PEC Tools. Very nice, American made squares and rules, for 20-30% less
than the big three. And no, I have no other affiliation other than
being a satisfied customer. Bought my set through MSC.
All that said, your best deal might come from a monthly special at
your favorite vendor. I don't think you will be dissapointed with a
square from any of the above manufacturers.
Also, you might find an older square at a neighborhood garage sale. I
have an old MIller Falls, which is fine for wood dorking activities
and general home use. It is a step above the junk Stanley and General
squares sold at the BORG.