Source: https://sozai.app/transcript/youtube-video-transcript-495/ Tutorial on reading a 0-25 mm metric micrometer caliper: sleeve scale in millimeters, 0.5 mm pitch thimble, and reading the 0.01 mm thimble graduations. ## Key Takeaways - On a metric micrometer, the sleeve reads full millimeters above the datum line and half millimeters below it - The thimble has 50 graduations of 0.01 mm each, with a 0.5 mm pitch screw - Final reading = sleeve reading + thimble reading aligned with the datum line - Using the ratchet stop and locking nut ensures consistent measurement pressure and stable readings ## What the video covers - Introduces a 0-25 mm metric micrometer caliper, which works like the inch version covered in the previous video; only the scale differs - Explains the sleeve (main scale) showing full millimeters above the datum line and half-millimeter graduations below it - Describes the 0.5 mm pitch screw: one full thimble revolution moves the spindle half a millimeter - Walks through reading the main scale by counting exposed millimeter marks on the sleeve - Demonstrates adding a thimble reading of 0.2 mm when the 20-22 marks align with the datum line - Shows measuring the outside of a part: opening the anvil and spindle, locking the ratchet stop, and reading the result - Example measurement reads 12.5 mm on the main scale plus thimble reading, giving approximately 12.2 mm for the sample - Explains the thimble graduations of 0.01 mm each, with 50 graduations per revolution - Emphasizes checking the datum line to determine where the measurement starts ## Chapters 1. 00:00 Introduction to the metric micrometer 2. 00:40 Reading the metric sleeve scale 3. 01:57 Understanding the datum line and thimble pitch 4. 03:17 Measuring an outside part 5. 03:34 Reading the main scale and thimble values 6. 04:16 Thimble graduations and final reading Answers ## Questions about this video What is the measuring range of the micrometer in this video? The micrometer covers 0 to 25 millimeters. It works the same way as the inch micrometer from the previous video, with only the scale being different. What is the pitch of the screw and what does it mean? The screw has a 0.5 mm pitch, so one complete revolution of the thimble moves the spindle half a millimeter. This is why the sleeve shows half-millimeter marks below the datum line. How is the final measurement calculated? Add the main scale reading on the sleeve to the thimble reading aligned with the datum line. In the example, 12.5 mm on the main scale plus a 0.2 mm thimble reading gives a total of approximately 12.7 mm, though the transcript's final figure is partly unclear. ## Full Transcript — Download SRT & Markdown 00:01 Speaker A This is a 0 to 25 millimeter metric micrometer caliper. It functions exactly the same as the last video's inch micrometer caliper. The only difference is the scale. 00:19 Speaker A So again, we're Going to measure Across the Screw, We had a look at in the last Video Tightening The Ratchet Stop and Locking the Locking nut Now We'll have a look at the Scale Zoom in Just A bit 00:40 Speaker A So in this video, we'll learn how to read the metric scale. 00:57 Speaker A On the Sleeve I'm Seeing [0] then A [5] do you remember the inch Micrometer It was 0 Then A 1 Then A 2 this one Goes 0 5 10 15 20 if We reveal Underneath the Spindle? 01:12 Speaker A Again, we're going to measure across the screw. We had a look at this in the last video: tightening the ratchet stop and locking the locking nut. Now we'll have a look at the scale. Zoom in just a bit. 01:33 Speaker A 0.5 Millimeters Pitch so every Time We do One complete Revolution of the Thimble it will Move the micrometer half A millimeter that's how this One's Based So again all we're Seeing on the Main Scale are Full Millimeters? 01:49 Speaker A Okay, so again, looking at the datum line. This is where the measurement is taken from. The datum line on the sleeve. This one is a little bit different from the inch one, and it should be recognizable right away to you. 02:09 Speaker A [We] know on the sleeve There are Six Millimeters Exposed? Now, We have to come over to the thimble because we're Past? 02:17 Speaker A On the sleeve, I'm seeing 0, then a 5. Do you remember the inch micrometer? It was 0, then a 1, then a 2. This one goes 0, 5, 10, 15, 20. If we reveal underneath the spindle? 02:39 Speaker A so with that mind if We have a look at this I can see the 20 I Can See, the 21 I can see The 22 So the answer for the Thimble Should be Point to two millimeters 0.2 0.2 02:57 Speaker A Do you notice there are five graduations above the datum line? Each graduation is one millimeter. Do you notice how there are five short graduations below the datum line? Each one of these is a half a millimeter. So every revolution of the thimble will move it a half a millimeter. The screw on this is 0.5 millimeters pitch, so every time we do one complete revolution of the thimble, it will move the micrometer half a millimeter. That's how this one's based. 03:17 Speaker A [We] had Done With the inch One We'll Take the measurement of? The Outside of This Piece so I'm Just [Opening] the anvil and Spindle to fit over [it] again will click the ratchet stop Lock it Pull the part out 03:34 Speaker A So again, all we're seeing on the main scale are full millimeters? So 0.5, 1, 1.5, to 2.5, 3, 3.5, for 4.5, 5. I can see another one here, 5.5 millimeter. Can you see the 6 millimeter graduation on the sleeve? 03:48 Speaker A 11 and [1/2] 12 I Can Just See the Point Five Millimeter line Exposed so the answer Should be [12.5] on The Main Scale 12.5 Millimeters and Then if We have a look up here it's Almost 2.2 so the answer Should be 04:16 Speaker A We know on the sleeve there are six millimeters exposed. Now we have to come over to the thimble, because we're past the six millimeter graduation. Each graduation on the thimble is 0.01 millimeters, so it'll go around: 0, 5, 10, 15. I think you can just start to see 20, 25, 30, 35, 40, 45, all the way up to 50, or 0.5 millimeter, each one being 0.01 mil. Topics: metric micrometer micrometer caliper 0-25 mm micrometer reading micrometer thimble sleeve scale datum line measurement tutorial precision measurement machinist tools Study this video - [Flashcards from this video](https://sozai.app/tools/ai-flashcard-generator/?from=transcript&id=88103) - [Quiz on this video](https://sozai.app/tools/quiz-generator/?from=transcript&id=88103) Free, made by AI from this transcript. No signup. --- This is the markdown twin of https://sozai.app/transcript/youtube-video-transcript-495/ — the same content, without the markup. Published by SozAI (https://sozai.app). Reuse and quotation are allowed with attribution and a link back. Machine-readable index: https://sozai.app/llms.txt · data API: https://sozai.app/api/