- Hello, and welcome to
this Haas Tip of the Day. What I hold in my hand is
the modern world, the result of thousands of years of
manufacturing refinement. Okay, a bit much, maybe? This is actually a hub for our
side-mount tool changer arms, but what it represents is incredible. The fact that we can measure
every feature on this part with near certainty allows us to machine perfect part after part,
and those can be shipped all over the world where
we know that they will fit into an assembly just as designed. Part interchangeability in
our modern assembly lines are only possible because
of good machinists making and measuring,
measuring, good parts. Now in today's video,
we opened up our toolbox and we pulled out some of our most basic hand measuring tools, (laughs) okay, okay, some of our most basic
handheld measuring tools, and what's needed to use
'em, so stick around. Everything for me begins with my setup. So check this out, I've
got a block loaded up. Now if you're tightening
up those tools by hand. (cheerful music) These are the measuring tools that we're gonna take a look
at today, and we're gonna spend most of our time on
calipers and micrometers. If you work in a machine shop, this is what you have to
master if you wanna progress in the trade, so we're gonna
start with our trash bags. Where else would we start a
video on measuring tools, right? So let's take a look at the fine print. It says here that these bags are 1.1 mil or 27,9 ums thick. Did I sound like a machinist when I read off (laughs) those numbers? Nothing I said sounded like a machinist. So can anyone tell me how
thick these trash bags are in inches or in millimeters? There are still some
industries here in the U.S. that refer to 1/1000ths of
an inch, .001, as a mil. You might hear that term when measuring the thickness of paint
or a plating thickness, or when measuring the thickness of plastic sheets or plastic bags. But as machinists, we
don't use the term mil. It just doesn't sound right. We use the term thou, as
in 1/1000ths of an inch. Mil sounds too much like
millimeter and it's just confusing, so we need to learn the
slang of the machinist if we wanna be understood. This is one inch, 1.0. This is 1.1 inch, or one inch, 100 thou. This is 1.15 inches, or one inch, 150 thou. This is 1.157, which is one inch, 157 thou, and this is one inch, 157 thou and 5/10ths. This is basic stuff,
but that just makes it all the more important to
get right around the shop. In the same way that the
thou is the base unit for the way we talk in the inch system, the um is the base unit for
the metric system (laughs). Okay, it looks like um.
(singer humming) But don't call it that, okay?
(record scratching) You'll sound really, really
weird, like I did just now. This is actually a lowercase Greek mu followed by a lowercase M,
and this stands for micrometer in the metric system,
one millionth of a meter or 1/1000ths of a millimeter. Now to avoid confusion
between this micrometer and this micrometer, we just call 1/1000ths of a millimeter a micron. So .001 in the imperial
system is one thou. .001 in the metric system is one micron. That means that these trash
bags are 1.1 thou thick, about 28 micron. That is how a machinist
speaks, a thou and a 10. Now these trash bags over
here, three mil thick, which is three thou
thick, or about 76 micron. Ooh, this might be a great spot to mention that there are exactly
25.4 millimeters per inch, so we can use those numbers to convert from millimeters to inches
or inches to millimeters. Well, now that we know the
language of the machinist, thou and microns, we can
move over to our yardstick. Now on this yardstick,
the graduations come, oh, a graduation is just
the line that we measure to. On this yardstick, they
come every 1/8th of an inch, so one divided by eight equals .125 inches or 125 thou. Here in the States, you've
gotta get really good at converting between
fractions and decimals, so 1/8th of an inch, 1/4 inch, 1/2 inch, 3/4 inch, and so on. Now for the metric meter stick, the graduations come every millimeter. There are 10 millimeters in a centimeter and 1,000 millimeters in a meter. Way over here on this meter
stick, if we look right here, we could call this 58.5 centimeters or 585 millimeters, either way. So this is our meter stick, our yardstick, and it is not the most
accurate measuring tool. Now our tape measures
are only slightly better, but they're really useful as machinists when rough cutting material. Right off the bat, I might think that this tape measure is broken. The end is all wobbly. Now how accurate can that be? Not so fast (laughs), it's not broken. The end hook on a tape
measure is supposed to move. The hook is slotted so it
can slide on its rivets forward and back by the width of the hook. It can give accurate measurements while either pushing or
pulling, genius! (laughs) Now I know this is basic,
but it's good, right? Every machinist needs to know this. Accurate measurements start
with knowing your tools. Now actually, over the last few years, I've seen more and more ads online that actually specifically
ask that operators know how to use a tape measure. It's the basics. So on an inch tape measure,
the graduations are now coming every 1/16th of an
inch, one divided by 16, .0625, 62 1/2 thou. For metric tape measures, the graduations are still
coming every millimeter. No big change there, pretty consistent. Here we start getting into
some machinists' tools that are accurate enough to make some pretty decent measurements. I'll often carry around one
of these in my shirt pocket. Now a lot of us got scolded
at our first machinist jobs for calling this a ruler. The old guys will chime in and say a ruler is a king or a queen. This is a scale. What's funny is that these typically aren't scales anymore, either. Back in the day, our grandfathers
would hand-draw prints using architect or engineer scales to get the proportions correct when not drawing parts life-sized. When a drawing is the
same size as a real part, we call that scale 1:1. If the drawing is half
the size of a real part, the scale would be 1:2. Now here are my grandfather's old scales with different ratios. The graduations on them vary based on the scale we
wanna draw the part at. The machinists' rulers or
scales that I use today typically have a precision edge on them and they're just called steel rules. These typically come with graduations of 1/32nd and 1/64ths of an inch, while metric steel rules will go down to millimeter and one-half
millimeter graduations. So our rulers that we've looked at have graduations all over the place, 1/8th inch, 16th, 32nd,
and 64th graduations. And this can get really confusing. We've just gotten used
to it here in the States and we've gotten really
good at converting fractions into decimal inch values, which brings me to one of my favorite machinist quotes. Instead of our engineers and machinists thinking in eighths, 16ths,
and 32nds of an inch, it is desirable that they
should think and speak in tenths, hundredths, and thousandths. This was written by Sir Joseph
Whitworth way back in 1857. In fact, he coined the term thou, 1000ths of an inch, way back in 1844. Thank you, sir. So the steel rule that I tend to carry most often in my pocket is
actually a decimal inch version. It'll have the .1, .2, .3 inches on the one side, which match up well with our decimal inch digital micrometers that we were looking at,
and our Haas control, which doesn't list things in 64ths. It lists things in decimal inches, so no more scant or heavy 64ths. This is by far my favorite steel rule. Now if you wanna look
like a real pro when using a steel rule, be sure to set
it on its edge when measuring. You'll get much more accurate
and repeatable measurements. By placing the rule on its
edge, we avoid parallax, where the measurement
appears to change on us based on the direction we
view the graduations from. Each of these measuring instruments has a different accuracy of precision that a trained person can
be expected, trusted to hold with one of these instruments. Often, but not always, the accuracy or precision of an instrument is the same as the smallest graduation on that tool, so our yardstick had
1/8th inch graduations, and these calipers here,
ah, which have to be the most versatile tool on this table, have a resolution down to 5/10ths, while these dial calipers here have a smallest graduation
resolution of one thou. Now in reality, I don't use
calipers for numbers that small. Once I go down below a
couple of thou or a thou, I'll start using micrometers, so that's just typically what we do. Why push the limits? To be used accurately,
these need to be zeroed out with each use, held square to the part, and used with just the right
amount of force, not too much. We'll wipe the reference
surface with a lint-free cloth and we might wipe that same surface with a drop of micrometer oil. We'll open and close the
calipers to make sure nothing is dragging or catching,
and if the calipers drag while opening or don't
fully close, the calipers might have been damaged
and they'll need repair. We'll wipe clean the measuring
faces and close 'em snugly. We can hold the calipers up to a light to make sure there is
no gap between the jaws. If there is, clean 'em
again or get 'em repaired. With the jaws closed, we'll
origin or zero out the calipers. I'll open and close 'em
a few times at this point to make sure I get zero repeatably. We can zero out dial calipers
by rotating the bezel and snugging the set screw. These calipers are like
the Swiss Army knife of machinist tools. They can be used to
measure inside features, outside features, depths,
or a step or a shoulder. I have five things for
you to watch out for when using calipers as
you gain experience. One, don't push too
hard, and keep the part as deep in the jaws as possible. It's a good idea to hand a
new machinist a gauge block or a standard to practice with
when they're getting a feel for how hard to press. If you don't get the number on the standard gauge block or pin, then you are pushing
too hard or too lightly. Number two, make sure that your calipers are square to the part
that's being measured. If they're tilted, you
could end up with errors. Number three, watch out for
the radiuses left by tools. These can throw off your numbers. This part has a 10 thou
inside corner radius, which can affect my values. In this case, I just rotate the calipers to allow the notch on
the depth-measuring face to avoid that inside radius. Number four, these calipers
are great for measuring IDs, inside diameters, of
holes, but not small holes. When a hole is smaller than
four millimeters' diameter, 157 thou, these inside diameter jaws aren't gonna fit cleanly, and
your numbers are gonna be off. You'll usually show the hole being smaller than it actually is. This happens just because
of the physical design of all calipers, even the good ones, so for really tiny holes,
you're probably better off going with a small bore gauge
or gauge pins of some kind. And number five, if you're
using a dial caliper, make sure you're looking at
the needle from straight on. If you're looking at it from the side, we'll get parallax error,
like we saw earlier with the steel rule. Once you're getting some
good measured numbers with your calipers, we can try
some advanced caliper tricks, like coming up with the
center to center distance between two holes. By zeroing out your calipers
on the ID of a hole, you can then easily check
the center-to-center distance between holes of that same diameter. This makes reverse engineering
some parts go really quickly. This little trick is why I prefer digital calipers over
dial, that and the fact that we can change them
from inch to metric quickly. And they look great in a holster. (dramatic cowboy music) For more precise measurements, we're gonna set our calipers down and move up in the world to micrometers, not to be confused with
micrometers (laughs), okay? Now the biggest difference,
one of the differences, between calipers and micrometers
is that calipers can work across an entire range. These are eight-inch calipers. They work from zero to eight inches. Now micro (laughs), micrometers,
have a limited range, usually one inch or 25 millimeters. Now this set of micrometers, which covers zero to six inches, requires six different micrometers,
zero to one, one to two, two to three, five to six, et cetera. The reason I mention this is that they are zeroed
differently, and micrometers, the zero needs to be checked
with every use, right? And so this is something that's important. Look, the spindle on these
one inch or 25 millimeter mics can close all the way
against the mic anvil, all the way to zero, and as I do that, it's a good time to check to
make sure that there's no drag, kinda like when we were opening
and closing the calipers. As I close up these micrometers, if we feel a drag of any type,
they may have been damaged and they might need repair,
or maybe the spindle clamp is tightened just slightly
and needs to be released or at least cleaned up. You can use some micrometer
oil and clean those spindles. To clean and check zero on these, we'll slowly tighten the mics, clamping against a piece
of lint-free paper. Once lightly clamped, we
can drag out the paper, which in turn cleans the measuring faces, and we can do this a few times. Now I've often used whatever random paper that's laying around to clean my mics, but this is a bit dangerous. If the lint from regular
paper gets stuck on the faces, it'll throw off all of our measurements, so lint-free paper is the way to go. Okay, all clean, no lint. Time to tighten up these
micrometers and check out our zero. Now here's where we run across what might be the number one
issue, cause of mistakes, when using micrometers. I'm talking about gorilla grip. If we over-tighten these mics,
(gorilla grumbling) our measurements can end up
being off by quite a bit. In fact, if you are buying
a set of micrometers, it's worth it to spend a little extra and get a force-limiting device, like a ratchet stop or a
slip clutch of some kind, which help give us a consistent clamp, whether measuring a part
or setting our zero, and it helps us prevent gorilla grip. Now for our digital mics,
we'll just close them and origin them out,
setting them back to zero. Now if we're using larger
digital mics, these big ones, we can clean the measuring
surfaces and origin them while clamped on a standard
or on a gauge block. Now for checking zero on our analog mics, we'll do the same thing. They're all closed, ready to
go, and they should read zero. If they don't read zero,
then we have to adjust them, and to do that, we're
gonna take a little wrench, the little spanner wrench that
came with the micrometers, and we're going to lock it onto the sleeve and rotate it slightly until
the lines line up, zero zero. Now this doesn't have to be done often, so if you're new to
machining and you think your mics aren't reading correctly, grab a buddy and have him
take a look at the mics before you make any adjustments. Again, that sleeve might be hard to turn if it hasn't been adjusted in a long time, so you might have to
clamp it in a mic vise. You might actually have to
tap on the spanner wrench just a tiny little bit with a hammer. With our mics all zeroed
out, we can measure a part. Now I'm gonna grab these
digital mics and this part, and I'll set it on here. We're gonna jiggle things to make sure everything's nice and square. We're gonna rotate our ratchet
stop a few revolutions, click, click, click, and
then there's our number, 595 thou and 2/10ths. Now to get that same
measurement with an analog mic, we're gonna have to read between the lines and do some addition. For inch micrometers, the main graduations etched on the sleeve are 100 thou apart, .1 inch, .2, .3, four, five. That's .5 inches. We haven't quite made it to six. We haven't graduated to .6. The smaller graduations on the sleeve are 25/1000ths of an
inch apart, 25, 50, 75, and we aren't quite to our next line yet, so we'll call this .575 so far. But wait, there's more. Now we move over to our
thousandths graduations, which are etched on
the micrometer thimble. Our highest full line number is 20, so we just add this in, .595, 595 thou. Actually, we're just a
little bit over that. We're kind of in between 595 and 596, so for higher precision
out to 1/10th of a thou, we'll look over to these
numbers, zero to nine, etched around that circumference
of the micrometer sleeve. These markings are part of
what we call a vernier scale, and there's a secret code to them. They help us read between the
thou lines, the graduations, on our thimble for higher
accuracy, higher precision. For this vernier
micrometer scale, all we do is look over all 10
numbers, zero through nine, and decide which one best lines up with the thou graduations on the thimble. Now it doesn't have to line up with any particular thou line. Any one of 'em will work. It just has to line up well. Our eyes can play tricks on us, so we have to be careful
to avoid parallax. Yeah, just like that steel rule. We need to look straight
down at those numbers. So finishing up our math
lesson here, we have .5 plus 25, 50, 75, plus 20, plus 2/10ths gives us .5952, 595 thou and 2/10ths. Metric micrometers are very
similar, with graduations of one millimeter and half
a millimeter on the sleeve, graduations on the thimble every
.01 millimeters, 10 micron, and a vernier scale on the sleeve, which lines up to an
accuracy of one micron. We'll see these vernier 10th scales on lots of different kinds of micrometers, so it's something we
really need to master. So that was some pretty solid instruction on calipers and micrometers,
our common tools. I'd like to quickly
gloss over bore gauges, gauge pins, and blocks
before we let you loose here just so you know what
people are talking about when you see 'em. Bore gauges are used to accurately measure
hole inside diameters. Now they are similar to micrometers in that they are only good
for a certain range of bore. This set comes with
adjustable anvils, rods, that can be swapped out or
stacked so the gauge can be used with different diameter holes. Now we'll typically
zero out our bore gauges using a precision ring gauge,
and we'll check this often. And like all dial gauges, we need to look straight at
the needle to avoid parallax, and digital indicators
can also be attached. Now for small holes, these plug gauges, also called gauge pins or go/no
go pins, are just terrific. Once the correct pins are chosen, if the go pin fits and
the no go pin does not, we can quickly gauge
whether a hole is in spec. Now you can order these
pins in varying tolerances based on how tight the print tolerance is for your particular feature. Now similar to our plug
gauge is our thread gauge, or our thread plug gauge. Now we'll order these up in a go/no go based on the callout from our blueprint. This is a 5/16th-18 thread with a fit tolerance of 2B. Now for most threads,
we'll check the hole size, the thread minor diameter,
with a go/no go pin, and then check the thread pitch itself with a go/no go thread gauge. This is a good thread.
(cash register dings) Some of you have noticed that I'm measuring this
particular part after coating. Now you'll need to watch out for coatings. This part has a black oxide finish on it, which is a conversion
coating and leaves virtually no buildup, so we don't
have to mask anything on it. If this were an aluminum
part getting anodized, you'd really have to
plan out the entire part, deciding if you were gonna
mask certain holes or not or if you needed to
machine the part undersize to account for the coating
that's gonna build up later. Most anodized parts might have a buildup of a half a thou to maybe
4/1000ths of an inch, depending on the type of anodize. Well, we really dove deep into
a couple of the common tools that we use every day as machinists, but we glossed over some
of these other topics. But we're gonna be making videos on those soon in the future, so
be sure to subscribe to the Haas Automation YouTube channel or like us on Facebook. Well, that's it for this
Haas Tip of the Day. Thanks for watching.
(cheerful music)
