Hi i'm bob welds and this is how to read a metric micrometer A micrometer is used to take very precise measurements There are different kinds of micrometers inside micrometers outside depth micrometers inch micrometers Just look them up on wikipedia. But here I have a metric one. This one measures to the nearest .01 millimeters. It says so right here As you turn the knurls the measuring parts open up. These are called the spindle and the anvil The spindle moves the anvil does not Now to get down to the business of reading this thing, let's take a close. Look at what's called the barrel scale I'll have sparky my dog help me out. He's a pointer You read the barrel scale by looking at the edge of the part that turns this part's called the thimble You begin by looking at these marks? You'll notice there are two sets of marks and a line the marks above the line are millimeters The marks below the line are half millimeters Let's stop here a minute and be sure you're with me What do you think the barrel scale is showing right now hit the pause button and think about it If you said 12 millimeters you were right if you didn't well there's more to life than being right all the time Well, let's take a closer look See 10 10 and a half 11 11 and a half 12 Here let's try another one pause the video and think about this one Do you see it reads 14 millimeters good let's move on Let's try another one. Now. This one's trickier pause it for a minute and see if you can figure out what the reading is Did you say eleven and a half millimeters See how there's a half mark showing that counts as a half millimeter. Great. You've got the barrel scale down Remember that we said this mic would measure down to the nearest one one hundredth of a millimeter Well, here's what that would look like on the barrel They don't really make marks this small because no one would be able to see them to read them Obviously there has to be a better way Remember that each mark on the barrel is equal to one half millimeter. Another way to think of a half is by saying 0.5 Another way is by saying 0.50 or 0.50? Now let's put 50 marks on the thimble As we turn it the thimble can count from 1 to 50 for us That means that each mark on the thimble is equal to.01 millimeters Now let's put all this together and try to figure out what this micrometer is reading first the barrel scale 10 11 12 So it's 12 millimeters plus something The something comes from the thimble scale. Let's zoom in 0.30.31.32.33 So the reading is 12.33 Millimeters Now here's one for you to try now it's trickier notice the half mark is showing on the barrel scale Let's see if you can figure out what to do with that Did you get 11.72 if so, you're really getting this. If not, you might have missed the half millimeter mark, let me show you Okay, first look at the barrel, 10 10 and a half 11 11 and a half now write that down Now look at the thimble 0.20 0.21 0.22 Now write that down now add them together and you get 11.72 Millimeters Okay, there's just one more small concept and will be done What if one of the marks is just barely showing do you count it? Is it ready to be used? Here is the trick Don't look at the mark to find out whether the mark is showing or not Look at the thimble You need to know if a new mark is starting or if an old mark is ending In this example, look at how big the number on the thimble is it's showing about 0.47 millimeters That's a big number for the thimble. Remember the scale only goes up to 49 Since the scale is nearing the end it's ending and so you don't count a mark. That's barely showing The trick is to find which side of the zero you're working on If you're not yet to zero, it's not yet a mark Okay, i've moved the micrometer just a little bit Now the mark is ready to be counted because the thimble scale is starting You see that the numbers on the thimble are small because the zero just passed by This means that the mark is ready to be counted Okay, so that's pretty much it there are some micrometers that can measure even more accurately than this They have a thing called a vernier scale on them I can show you how to read those another time if you want. Just let me know. But for now this should get you started Thanks for watching. I'm bob welds and these are weld notes You
