Micrometer Basics: Use, Care and Calibration

Per the request of multiple viewers, I have put together a video detailing the basis of using, caring for and calibrating micrometers as used in a machine shop for precision measurements.

[@marklowe7431]

I think many machinists don't realise how talented they are. I think engineering skills like this is very understated.

[@swarfrat311]

Keith, Thanks for the lesson on mic usage. After my Dad retired, he took a class to become a piano turner and repair tech. He had tons on different diameters of piano wire. He had a 0 - 1 Brown and Sharpe mic and I learned its use measuring piano wire. (He also had a wire gauge, but it was more fun using the mic!) I thought it was great fun! In my mid teens, I could do something to help my Dad. I felt useful and he appreciated the help. I will always have fond memories helping my Dad. Thanks for the video and for reminding of great times I had as a kid. Have a good one! Dave

[@VintageMachinery]

+Swarf Rat The micrometers get used in a lot of areas besides the machine shop. I never thought of using it for piano wire! I gave one of my spare micrometers to one of the coaches of our 4H BB Rifle team and taught him how to use it to measure BB's before a competition so that they were shooting uniform size shot (you would be amazed at how much variation there is in regular BB's).

[@colbybrown482]

Thanks for the video, Keith. Answered so many questions as I get started with my first micrometer.

[@itbigboy1984]

Thank you Keith, great info and a great refresher for an old mind!

[@leonardwinn3446]

As others have said, a great video. Only two things I would have added. A micrometer is not a clamp, do not over-tighten on the part being measured.In order to avoid this, use the ratcheting knob until you develop a 'feel' for the instrument. Thanks again Len

[@williamhardin5254]

Great tutorial. It doesn't seem to matter how many videos I watch about using tools I always seem to take away something I new that I didn't know. Everyone seems to have a different way of teaching the use of a tool. I love watching this type of video.

[@VintageMachinery]

+William Hardin Thanks - my pleasure to give my spin on reading mics!

[@jonathanpadgett514]

We just went over the parts and uses of micrometers in my machining class yesterday. Your video really helped me understand the parts better. Thank you for your great videos.

[@VintageMachinery]

+Jon “Meatandtaters” Padgett Great! I am glad that it was helpful for you! Get a micrometer out and start practicing - that is the only way you will ever really learn how to use one.

[@jeffmoss26]

Great video Keith. Informative as always!

[@silveradoman298]

Thanks for this video Keith. Of all the youtube machinists, I don't think ive seen any of the guys, except mr pete, give a basics video on anything for those who are not familiar with the tools or are new to metal working.

[@VintageMachinery]

+silveradoman298 You know, it is one of those things that I think so many of us take for granted. If you work in a machine shop, you know how to read a micrometer. But we KZbin producers have to remember that a large part of our audience does not have this experience. It took some of my viewers to remind me of that and this video is the result!

[@LightAndSportyGuy]

A couple weeks ago you said you were going to be busy at work (and traveling, if I recall correctly) and not to expect a video each week. Now, it seems to me that this is the 4th video you have posted in the last two weeks. Admit it, Mr. Rucker - you can't help it. ;-) And, we appreciate it!!! Seriously, thank you for your work. I've watched every one of your videos and enjoyed them all.

[@VintageMachinery]

+GeoffreyThorpe123 Thank you for watching them all! Things are about to get busy for me later this month, but for now, I am managing to keep the videos coming. I am going to try and save a few up for some of the weeks coming up that I know I won't have any shop time.....

[@ianbertenshaw4350]

Hi Keith, I have never seen anything like that little Starrett mic with the spring loaded thimble ! Very nice ! I have different levels of measuring tools from cheap junk up to mitutoyo and starrett etc , i use the cheap stuff for things that are not critical and when they get flogged out i chuck them in the bin this saves my good tools from wearing out. Thanks for another enjoyable and informative video !

[@VintageMachinery]

+ian bertenshaw I got that Starrett mic with a set of micrometers that I bought off of Craig's list a couple of years ago. When I first saw it, I had never seen one like it. Once I figured out how to use it I thought how great of an improvement it is! Like I said, I wish that Starrett made that model in more than the 1" size. I too have some cheaper measuring tools that are my main go to tools and save some of my good stuff for when I really need accuracy!

[@turbocobra]

I always learn a lot from your videos Keith, but not really knowing how to read a mic, this is most helpful, and as you said pretty straight forward and doing the math in your head comes pretty quickly, thanks for taking the time to make this!

[@VintageMachinery]

+turbocobra Glad to help!

[@ChrisB257]

Excellent refreshed Keith - probably of great interest to many newer folks.

[@VintageMachinery]

+ChrisB257 I am somewhat surprised as the number of people who were asking for this. But I forget that not everybody out there knows this stuff!

[@AkubraHatman]

Great video mate. Thanks for teaching us how to use these tools.

[@ericsnyder1647]

Thanks, Just in time! I just picked up a used 0-6 Mitutoyo box set. You did an excellent job. Thank you !!!

[@VintageMachinery]

+Eric Snyder Glad to help!

[@carrollprice1213]

Excellent! Thank you Keith. All we need now is a battery and pushbutton to prevent physical exertion needed to run the thimble up and down.

[@tedsykora1858]

I have never seen or used a vernier micrometer and so I found that useful and interesting.

[@Rich206L]

Keith, this video was OUTSTANDING! It brought me back to 9th grade shop class (shop, what's that? Now we know why we are where we are as a nation. Anyway). Yes, not a hard thing to do once you "Get It". I tell you, all things in life should be this simple. You did a great job explaining how to use this tool, and those of us who watch you, Fenner, Abomb and others, can now see the mystery of this device sent bye-bye. It also shows what great teaching talents you have. Hey, you can get a job at one of the Universities in GA, 20 min from home, then you can spend more time entertaining and teaching US! :) Lastly, I have to say that every time I get a notice that you've posted something, it has me salivating about that damn furnace and the safe! I know it's coming, but thanks for these great "in between" videos to keep us involved. That's the one thing that sets you apart from all the others, it's your consistency, at least one video a week. I hope I can get the chance to meet you one day. Regards, Rich

[@VintageMachinery]

+Rich206L LOL - I actually spent about 12 years of my life working for the University of Georgia. Not as a professor mind you, but as an Extension faculty member. Been there and done that and glad to be back to working in the private sector now.... The furnace project should be coming back up again soon. I am really trying to concentrate on finishing up the Vance but I do have what I need to do give the furnace another try. What I really need is more time....

[@billdlv]

Keith thank you for posting this video. I know there are a lot of videos out there on this subject. I was taught by my auto shop teacher, then through the years others showed me some tips like using your forearm as a surface to run the thimble open or closed rapidly. I remember having a whole lab experiment in physics class on reading inch micrometers, metric micrometers, and vernier calipers. Each time I see a different person, I usually take away some little tip. I think it is valuable to always look at how you are doing things and compare it to others to make sure you are doing it the best way possible. All too often I feel like it is too easy to say "I always have done it this way" or worse yet hear from your boss we always due it this way. The more important question I feel is ""Is this the best way?" Then you are thinking more about what you are doing, and also how to define best.

[@VintageMachinery]

+Bill De La Vega Thanks Bill - one of the beauties of KZbin is that you can see how others do things that you might do differently and pick up new tricks along the way. I have had I don't know how many requests to do this video for some time now and I am somewhat surprised by all that are so thankful for me posting. I guess I just take it for granted that people know the basics when many don't or may do things differently.

[@lewiemcneely9143]

+Bill De La Vega Perxactly! Just because the comment floats around that "This is the way we've always done it" or That's the way we've done it for the last ten years" doesn't mean that's the best way to do it. Always learning. Good comment, Bill. My hero Uncle was named Bill and he always told me "You can't learn too much" and "LOOK at what you're looking at". Always worked for me but irked a lot of others.

[@thadstuart8544]

you are a really, really good instructor. thanks

[@PeterWMeek]

Very useful video. Thanks. A couple of observations: When using the smaller micrometers (0" to 1" and 1" to 2") it can help protect them from being dropped if you curl your little finger through the frame. This gets a good safe grip on the micrometer and locates the forefinger and thumb perfectly for turning the thimble and holds the graduations in a position where they are easy to read. Most drops seem to happen when you are changing your grip on a micrometer, and this cuts how often you need to change your grip. You can also make large changes in the opening size by rolling the thimble up or down your opposing forearm, all without changing your grip. (Just don't "slam" a 0" to 1" micrometer down to zero using this rolling method; it can bend the frame slightly, and require re-calibration, or even require getting the anvil reground to make it parallel with the spindle face again.) Second observation is only peripherally about micrometers: People frequently wonder why there is usually a pocket on a machinist's shop apron that swings out (instead of being sewn flat like all the other pockets). A micrometer is usually the most valuable small tool owned by a machinist, and the most easily damaged. The swing-out pocket is to prevent the micrometer from falling out of the pocket when you bend over to pick something off the floor or a low location. Once you think about this, you will see that the swing-out pocket is exactly the right size for a 0"-1" micrometer and will hold it upright to make it easy to get a good grip on the thimble as you pull it out of the pocket. (Don't forget to put your little finger through the frame as soon as possible.)

[@VintageMachinery]

+Peter W. Meek Peter - thanks for the tip on the little finger. I will try that, but it will probably take a huge effort on my part to train myself to use a different technique than what I have been doing for years. Hard to teach old dogs new tricks.... About the shop apron pockets, the swing out feature is handy for pretty much whatever you put into those pockets!

[@PeterWMeek]

It was how my grandfather taught me to hold a micrometer (after he got over discovering me using his micrometer for a C-clamp) back around 1950. Once he had re-lapped the anvil parallel to the spindle (that's how I know about that) and recalibrated it, he taught me how to use it. I was set to making 1" cubes using a vise, hacksaw, file, micrometer and square. They had to be closer to 1.000" than to either 0.999" or 1.001" (so ± 0.0005), and no light under the square at any location. I have to say it taught me how to use a hacksaw and file efficiently and carefully. Go undersize and start over. Age about 7 or 8.

[@TheChipmunk2008]

+Peter W. Meek He got over that? :O LOL

[@PeterWMeek]

Getting a bit off topic, but my grandfather (according to family oral history) once had a really terrible, violent temper. Apparently, about 35 years before I was born, my grandmother told him that if he ever lost his temper again, she would leave him flat. No remorse, no "i'm sorry", no nothing; just gone. By all accounts, he never lost his temper again. It may have turned him into the extremely successful company owner that he turned out to be, but he never lost his temper again. At any rate, he was clearly unhappy about what I had done, but spent time explaining the difference between a C-clamp and a micrometer. and then set me to making cubes.

[@PeterWMeek]

BTW, my grandfather and grandmother were childhood sweethearts from the time they were 7 years old in a tiny village in Sweden.

[@kentuckytrapper780]

Great info Keith, keep'um coming..

[@ianmoone2359]

Fantastic Keith, thank you so much for that explanation, really sincerely appreciated. 👍👍👍🇦🇺

[@InternetOverdosage]

IANNNNNNN 🧢😂😂😂

[@ianmoone2359]

Tommy Painter Why so funny? I just spent $3k on a set of Mitutoyo 0-12 inch gauges with matching extensions sets for calibrating them. I had zero idea how to use or calibrate them & now I do thanks to this excellent tutorial. I saw them going cheap, have t even bought my lathe yet, but knew I was going to need them when I do! So I grabbed them while the grabbing was good. Now I know how to use & calibrate them I am even more pleased with my purchase. I have zero machining background - I’m a wood worker all my life. This is all new to me, so I sincerely appreciated the video & have saved it so I can refer back to it when needed.

[@InternetOverdosage]

Ian Moone you didn’t have to explain anything I have this due In a shop class I’m doing virtual it’s jus funny how old videos help so much

[@SuperYtviewer]

Thank you for demonstrating and explaining the type, use, and function of the micrometer. I missed that in the basic shop classes way too many years ago. I appreciate the basic branch mathematical (math) steps to go from decimal to imperial. ;-) Annie

[@VintageMachinery]

+SuperYtviewer Thank you for watching and commenting!

[@KnolltopFarms]

Great to play along with the video using the mic I traded you for, he he! Always good to keep in practice and wipe them down to feel connected. Take care and have a great week, Aloha...Chuck

[@VintageMachinery]

+Knolltop Farms Thanks Chuck!

[@fabiandaroca]

Thank you Mr. Rucker! I'm an estate liquidator and recently consigned a whole lot of machinist tools. Your video's are very helpful to me and my learning of these instruments...

[@DougHanchard]

Excellent video Keith. If I may add two things. Readers should be aware that the type of material and ambient temperature make a difference. As an example, measuring cast iron material at a temperature of 45 F compared to 75 F will be noticeable. This includes the micrometer itself and its accuracy will vary depending on what materials it is made from. Some materials expand / contract at greater or less rates than others based on temperature. Most machinist hand books have charts for material expansion rates. As mentioned by another subscriber, radius measurements (inside or outside) can be tricky. This is particularly true with some micrometers and everything can go bad in a hurry if clearances must be specific relative to the type of machining required. This has been partly solved with some models designed with a ratchet collar inside the thimble, for precise (and consistent) pressure against the radius part. This helps the operator of the micrometer become more consistent. I hope this video helps the novice to not worry about trying micrometers ! Best measuring invention ever created (James Watt). For beginners, some newer models have dual measuring capability, both digital and vernier scales.

[@VintageMachinery]

+Doug Hanchard I had on my list to cover temperature when I shot this video but it never got done. I just forgot to mention it.... Oh well. If guys watch my videos though they will commonly see me waiting for a part to cool down before measuring so maybe they will pick it up there.

[@BradsWorkbench]

Love ur website. Never knew y’all had a KZbin channel.

[@DavidHerscher]

I've found that tolerances on the lead screw for most "well made" mics are very tight. Meaning, adding oil, even light oil, will often stiffen them even more as the oil takes up space. I've found that oiling them, and then wiping off the excess completely so that it just leaves a very fine surface coating works best. I've learned this through buying old used mics from flee markets and ebay as i can't afford to buy nice tools new.

[@MrUbiquitousTech]

Great lessons Keith, thank you!

[@VintageMachinery]

My pleasure!

[@mxcollin95]

Great video! 👍

[@dannynimmo3052]

Your the only one I've seen with the starrett 221, I've got a couple, I use mahr indicator mic's mostly but that is a good in between regular mic but not quite close enough for the indicator mic. I do centerless grinding, usually tolerances in the tenths or one tenth total not uncommon. Thanks for the video, This is great, In the past I'd hand a new guy the instructions from a micrometer box if I didn't have to much time to explain. This is really nice, I'll use your video its good stuff

[@AGilbert_81]

Fairly new to this and this vid helped a whole lot.

[@jeffhayes4845]

Perfect timing! I picked up an old Craftsman 1" micrometer at an estate sale a few weeks ago and I was wondering how I was going to learn how to use it. Thank you.

[@VintageMachinery]

+jeff hayes There you go! Glad to have been a help.

[@jimkoonce6574]

Nice refresher, thanks Keith

[@VintageMachinery]

+Jim Koonce My pleasure!

[@daki222000]

little tip: I mostly check my micrometer reading with a quick "ball park" digital caliper (bozometer) reading, to be shure that I read it correctly. I am a beginner with this stuff, and this helps a lot. cheers. Thanks for the video, Keith.

[@VintageMachinery]

+Flip de boer Nothing wrong with that at all if you are just making sure that your numbers match. But, be careful and don't rely on the digital calipers too heavily as the micrometer is generally more accurate.

[@daki222000]

Shure, if the bozometer reading is in the ball park, I'll always go with the micrometer reading, but I have had a few occasions when I messed up with reading the micrometer. Especially when reading shows roundabout the zero on the timble, when the reference line on the micrometer body is just starting to show; or are you allready past it? (suddenly your part is precisely 0,5 mm off, and you immediately know where that came from..) i cannot afford Starrets (yet), which probably do not have this issue so much due to crispier engraving.

[@PhilsProjects]

Very informative Keith, thanks

[@VintageMachinery]

+Phil's Projects No problem - my pleasure!

[@PeakyBlinder]

Great vid thanks, From the UK.

[@djberg3483]

thanks sir, one more peice of knowledge stored, good lesson.

[@RookieLock]

Well explained! I just got a micrometer for measuring keys and key pins, for re-keying locks, I have been using a caliper but I thought Id get a micrometer aswell. Thanks for teaching me how to use it . :P

[@paulputnam2305]

Great Job, thanks

[@larryrobinson7492]

Good stuff Keith: I've noticed alot of people don't seem to know how to use or read Micrometers. I've been using them for many years but have never taken one apart or learned to calibrate one. I would like to know more about calibrating them. I don't have any accurate gage blocks or anything I could really trust yet. I'm sure there are plenty of videos on all that somewhere. Thanks.

[@colin8653]

good stuff Keith all good information thank you

[@VintageMachinery]

+Colin Samms Thanks for the feedback Colin!

[@jessefoulk]

Wow. A very high quality video. I like this one.

[@VintageMachinery]

+jesse foulk Thank you!

[@kylenavarro1672]

Thx a lot Keith !

[@phooesnax]

Thanks! Nice job

[@KennyInVegas]

You could be " THE WORLD'S GREATEST HIGH SCHOOL METAL SHOP TEACHER". Do they even teach "metal shop" any more? High school for me ended in '81.. I was fortunate to have wood shop and metal shop teachers like you. Those classes taught me more practical knowledge than anything else in H.S. Today I am a retired A.W.S certified welder who, because of those Industrial Arts classes, can repair and construct many things. Thanks for your time and effort...... GBYAY

[@VintageMachinery]

+Kenny A I was fortunate enough to have some really great shop teachers in high school as well. Mr. Dave Averett taught me Metals Technology and Mr. Chip Thompson taught me Wood Shop, Drafting and Small Engines. What a great foundation that those guys gave me! Not many programs like that left anymore, but there are a few still hanging on. Too bad....

[@jusb1066]

+Kenny A i was in school in the 80's UK and although our shops still had lathes (wood and metal depending on which shop you were in) along with metal forges, the various educational cuts meant we did none of those things, i think at most we cut a piece of wood once.....shocking lack of education i think, i have learnt pretty much everything i know after school from tv, books, people and now youtube

[@juanrivero8]

That was very nice. I learned on metric mikes in High School, principle is the same. One thing (and it is hard to do on video) you did not go into is how to tighten the micrometer down on say a round piece of work. This is "feel" and I think it is acquired with practice, especially if you have a tutor. I would love to see, at the next Bar-Z bash, a measuring contest. BYOM/BYOC (Bring your own mike/calipers) and see what the variance is between micrometers, and between micrometers and calipers. BTW you can get a very light oil -- sewing machine oil -- almost anywhere, including Wal-Mart.

[@VintageMachinery]

+Juan Rivero I like the idea of a measuring contest. That would be fun!

[@ianmoone2359]

Can I ask if using a spray can CRC-56 would be OK for lubricating the thimble screw on mitutoyo micrometers?

[@Bookerb2004]

Nice, thank Keith this helped a lot

[@VintageMachinery]

+Kelly Breckenridge Glad to help!

[@PhilG999]

When I was in HS (40 years ago) my science teacher gave me a German made 0-25mm micrometer. It was seized up. Apparently someone had tightened it down in the winter and with expansion in the summer it was tight. I clamped it in a vise and loosened the barrel. Took it all apart. Cleaned it. Did what I could to zero it. It's nice now.My Metrology Prof in College tried to buy it from me.I was the only student that could wring their old nasty gauge blocks...

[@VintageMachinery]

+Phil Grindle I don't even own a metric micrometer or any other measuring tools for that matter. I probably should have a few just in case as right now I have to convert any metric measurements I work with to inches.... Nice that you have one with good memories attached - those tools are priceless!

[@infoanorexic]

I just did a complete take-apart, clean, shine and "rough in" calibration on a Central Tool 1" - 2". Without a standard, I had to get rather creative in finding something to set it by. It involved a mag based dial indicator, two new and never used HSS tool bits and (another) new and yet to be used drill press vice. It consistently measures within 1/2 of 1 now. Not bad for a mic that started, with me anyway, as a "can't lose anything by trying" project.

[@VintageMachinery]

+diggerop Very cool! If nothing else, you made it better than it was and you probably now have a measuring tool that is worth using!

[@infoanorexic]

It certainly wasn't worth much being in the condition that I got it. Can't wait to get with someone that has a standard or a set of gauge blocks to see just how close I came to true calibration.

[@therealfranklin]

Great viddy, tovarich! oooOooOool your micrometers, meine bolshoye tovarichi.

[@IAutoEnthusiast]

Thanks. Very nice

[@h.k.nsingh1435]

Thanks for good video

[@kegtapper09]

Great video thank for sharing. Adam

[@VintageMachinery]

+Adam's Brewery and Shop Thanks!

[@pricetagg9730]

very nice video useful stuff thanks..keep it up...

[@VintageMachinery]

+price tagg Thank you for taking the time to watch and comment!

[@bharatbhushanbhushan7803]

Good teaching sir ji

[@israelbarrios1549]

excellent

[@BedsitBob]

Some of the lower end micrometers (I hesitate to say cheaper, because some aren't all that cheap) have a movable anvil, with which you calibrate them. My first micrometer (a gift from my father) had a movable anvil.

[@pandaward4671]

Isn't that a bit tight for the standard? If that was your material, your micrometer wouldn't be that tight would it?

[@PatFarrellKTM]

Nice overview. One thing that I wish you could cover is the use of the fine, ratcheting thimble that some micrometers have. I have one with them. I heard that I should use the fine thimble to apply a constant torque so that I don't get measurement error in the readings, but I'm not sure exactly how or why to do that.

[@VintageMachinery]

+Pat Farrell Yes, I should have covered that as well. Perhaps a follow up video is in order.... Yes, the ratchet knob will allow for you to have a constant pressure on the part which will give you a better measurement.

[@lewiemcneely9143]

+Keith Rucker - VintageMachinery.org I'm with Pat on that. If you get time I also wish you'd go into that aspect of it. I'm diesel powered and no nothing of such things although I worked around some dandy millwrights in my time!

[@patterickktube1907]

thank you sir for this video

[@VintageMachinery]

+patterickk tube You are more than welcome - my pleasure!

[@johnjohn-ed9qt]

Just rewatching, as I will be having my students watch this in a few months, and figured I'd throw my two cents in. Another viewer mentioned temperature, and to elaborate, if the mic is calibrated at 20C (68F), at 30C (86F), a 1" mic will have grown 0.0001" (a ten-thousandth) (most mic's, even old ones, have steel frames). Not a big deal in most cases, as even a tenths reader is usually only spec'd by the manufacturer to two tenths. If a steel part is at the same temp, say during springtime in Georgia, all good. If the mic heated up due to handling but the part is still cooler, error begins. If the part is another material, like aluminum, then the error is both due to the mic and the part and the tables need to come out. Larger mic's are more heavily effected. A 10"mic will grow by a full thousandth for the same temp increase. A tenths reading 10" mic is only good to 0.001 or 0.002" unless the temp is controlled and the calibration checked. At that size, a couple thousandths is usually going to be spec, anyway, but when tolerances get real tight, it is important. Worse yet is large mics may twist due to the heat of handling, and this will have a large effect. I did a demo a few years ago with a lattice(? Like the large one here, with holes to lighten it) frame 12" or so mic. Removed the spindle, had the students sight down the hole and see the reflection of their pupil dead center. Had a student hold it for a minute. Then resighted down the hole. Not only is the pupil not centered, but visibly way off. The frame heated unevenly from handling and twisted. Half hour later, just about back to center. Anvil and spindle faces not parallel, and the twist changes the baseline much more than uniform heating and cooling.

[@VintageMachinery]

You bring up a very valid point, and something worth mentioning. But I have to be honest with you that I don't normally worry too much about it. Why - because of the kind of work that I am doing. Most of my work is "job shop" repair work. Making a single part or two to fix something that is broken. I am usually measuring a piece and making another piece to fit it. Because of that, I have the luxury of being able to measure a part at whatever the temperature is in the shop and then machine another part to fit in a similar air temperature. In realty, the actual measurements I am dealing with are somewhat relative - if the actual measurement is off by a few tenths, it is no big deal as long as your reference measurement was off by the same amount. Make sense? For production work where you are meeting a specification, measuring in a room calibrated to 68 F is extremely important though. As such, your point is well taken and it is something that should have been in the discussion of using a micrometer or any measurement tool.

[@ogreunderbridge5204]

Nice. Thank you for the information. How about doing one on torque wrenches ?

[@EVguru]

Hi Keith, I like to remind people that an accurate zero is not an indication of a micrometer in good condition. Micrometers wear worst in the range in which they're used the most. It's wise to check them with gauge blocks at intervals over their measuring range.

[@VintageMachinery]

+Paul Compton Very true, particularly with older ones that have obviously seen a lot of use.

[@robinhoff4598]

I have a used 2” Starrett micrometer. The barrel knurling has a partial crusty ffingerprint smudge embedded in the knurling. Any ideas on how to clean this smudge. Recommended solvent? Tooth brush? Do you wipe your micrometers after use? Light coat of Starrett oil on a microfiber cloth?

[@MrShobar]

Ok for teaching arithmetic. But what cannot be taught here is the proper feel when measuring with a micrometer. That requires experience. Otherwise, a high quality video, as I've come to expect from you. Many thanks.

[@VintageMachinery]

+MrShobar You are so correct about the feel. There is no way to learn it except to get out there and just use them!

[@andreboy1]

I just got my first set of used Starrett 436 micrometers and was wondering what the ratchet function on the end is for. When I turn them they don't seem to move the spindle at all so I'm confused as to what this function is used for. Thanks.

[@EarthSurferUSA]

Note: There is a slight difference for calibration between using a flat standard and a round standard. Because of less anvil contact on the round surface standard, your mic will read about .0001" smaller than if calibrated on a flat standard.

[@BedsitBob]

Anyone have any thoughts on whether you prefer the ratchet as an extension of the end of the thimble, or built into the spindle, such as Moore and Wright have adopted?

[@BedsitBob]

Have to say, for 10,000th readings, I think I'd prefer the Vernier scale type, to the Starrett No 221 style.

[@stephaniesmith1999]

How do you hold/use big OD mics? I need to use 30-36 inch and I can't hold the anvil and thimble to at the same time. How do you keep the anvil stable and secure?

[@RoelTyros]

Hello Keith, Very interesting video because I never used an micrometer maybe because I didn't know how to use them. Now with your explanation how they work I understand the use of it and maybe I'm gonna buy also one. Not a really expensive one such as you have but it is always handy to have it with lots of precession measurements. Only thing I've asked myself was why most of the more bigger micrometers have a half rounded frame. Is there a special reason for because of strength or is it just the way they make them and has no special reason ? Again thanks for the video and many greetings from Roel !

[@VintageMachinery]

+RoelTyros You can find some nice used micrometers at a very reasonable price on places like ebay. As for the larger frames, as the micrometer gets bigger to measure larger sizes, it needs to have a larger frame for for measuring round stock. When measuring round stock (like on a lathe), you need to have a throat that is at least half the size of the maximum diameter you can measure.

[@bimatube1274]

Recently i bought a used Ammco 2250, kind an older micrometer. I don’t understand the ratchet mechanism, it doesn’t make noise or clicks when we turn. Its ratchet comes with a little spring. My question is, the ratchet doesn’t make click like the one that we see now a day. So how to know if the appropriate tension was set?

[@Ibedrunkalot]

Nice demo Keith the only thing you didn't mention is that temp can play a roll in the accuracy of the measurement

[@VintageMachinery]

+The Apprentice You know, I meant to mention that but it did not ever make it to video. Very good point though! Most inspection rooms where super accurate measurements are made are required to stay at a constant 68 degrees F +/-0.2 degrees F. And your parts should become normalized at that temp before measuring! But for most machine shop jobs, temperature is not as critical.

[@DaveInBridport]

I bought three micrometers on eBay for a song. My reason was for buying was to get parts for an existing metric one I own. I didn't realise that the collar inside the locking ring has a minute roller bearing in it. Probably 0.5mm thick. Only one of the micrometers has this...

[@leeh.4453]

Good lesson, appreciated. How tight to crank it down? Are the small ratchet knobs set up to apply the correct tension? Thanks.

[@jusb1066]

+Lee Humes yes some have the small ratchet at the end, some have a slip thimble for repeatable tension, only very basic mic's dont have this

[@VintageMachinery]

+Lee Humes As has already been mentioned, the ratchet knob will allow for the proper and consistent pressure when measuring with a micrometer. Some models don't have this feature, but I would consider it a must have option!

[@LoMe64]

Keith, nice video - thank you! But: You missed the most important thing when using a micrometer: NEVER NEVER EVER tighten the screw using the main drive! Every micrometer has two drives. The main drive (mostly the bigger, knurled one) and the measure-drive. The last one clicks when turning ist to the "tight" direction. So the tigthening force is limited to a defined value. And that is essential! Because you can build up A LOT of force with the fine thread. A micrometer is calibrated only whe using the clicking drive for the last tiny bit. I was shocked seeing you using the main drive when showing how to calibrate the 1-2 inch micrometer. Doing so gives an inaccurate reading and might also damage the micrometer. Lothar

[@VintageMachinery]

+Lothar Merl Point well taken. However, at least one of the micrometers I was calibrating did not have a ratchet drive. I try not to pick up micrometers without that feature but I have a few in the stash.

[@hugohell8290]

hello sir, what oil is this Starrett one that you are using? M1? thanks

[@willielocuaz]

Thanks for the info.. :0)

[@VintageMachinery]

+El Sratcho My Back My pleasure!

[@jankjensen222]

Thanks Keith, As ususal i learned a lot from you. Just one small question. How much pressure du you put on the dial when you take a measurement? I find it hard to be consistent, especially when measuring round items like axels... but then again i am only a selftaught "machinist" :-) Thanks again from Denmark!!

[@VintageMachinery]

+Jan K Jensen Most micrometers have a friction wheel at the end that will slip at a specified amount of pressure, which greatly helps keeping the pressure the same from one measurement to another. I highly recommend that you find micrometers with this feature, particularly if you are new to measuring with them. After a while, you get kind of a feel for using them and can do it without the friction wheel, but it is a nice feature none the less.

[@justinbell5696]

I'm sure Keith already knows this, but.. You can adjust tension on the threads to compensate for wear by adjusting the nut on the sleeve under the thimble. Do not adjust it with the spindle completely removed or it will get too tight and you will have to stick things in it that don't belong in the workings of a micrometer to loosen it up again. Just saying.

[@VintageMachinery]

+Justin Bell Yeah, I am aware of how that is done but I don't think I have ever actually had to use that trick on a micrometer. I did not want to get too advanced in this video as it was already too long.....

[@pfrieden1]

Fantastic video - a very practical and approachable intro to micrometers. I'm curious though - back in my chemistry class, we were always told to read to the last digit that was definite, and then estimate the last digit. For example, if I could read .234 for sure, and it looked like the line was right in the middle, we would call it .2345. Is that not recommended for micrometers?

[@VintageMachinery]

+Paul Frieden In the machine shop, I would not estimate much of anything as if you give a number for the tenths, somebody is going to assume that it was made with a precision measuring tool. If my tool measures to a thousandth, that is all that I would go by. But with that said, I will sometimes estimate to a half thousandth using a micrometer when I am working on something - but I would never write down or give that measurement.

[@geckoproductions4128]

Nice video, Keith, but what are the numbers on the frames and what are they used for?

[@VintageMachinery]

+GeckoProductions I think that what you are referring to is decimal equivalents for fractions of an inch. They made wall charts with the same info on it to quickly be able to convert a fraction to a decimal. Some of the micrometers have these decimal equivalents engraved right on the micrometer for easy reference.

[@moking1761]

Hi Keith, Just seen a KZbin video that may interest you. It's about making the bottle jack work better as used in your press. It's called 'Tinker Talk - Shop press bottle jack tip #2 by Eddie da Grouch. Regards MoK

[@VintageMachinery]

+Mo King I have seen that before. I think that Eddie actually sent me a note about it soon after he posted it.

[@claudiog.7397]

Handling the micrometer wouldn't alter the measurements? (Because heat from hands)

[@orange12v]

Hi Keith, can you please give a bit of advice repairing one I have 6"-7" J.T.Slocombe one & it's thread is binding at 6-6.5 end it came with a Moore&Wright thimble in it so I tried a thimble from a Slocombe 1"-2" I have & still binds in the same place also I tried the M&W thimble in the 1"-2" to see if the thread form was slightly different was the problem but they worked together perfect so it must be the thread in the frame any ideas how I can repair or change it?

[@VintageMachinery]

+orange12v Outside of finding a tap to clean up those threads, I really don't have any great suggestions. Sorry...

[@orange12v]

Hi Keith, Many thanks for getting back to me I also think a tap is the way to go as it's 40 tpi x 5/16" dia as it was made in USA any ideas what thread form it mite be? Regards Dave

[@stefantrethan]

Great video, although it was a little light on the use part (importance of using consistent torque, thus the ratchet on some. etc.). I expect these things are second nature to you so you didn't think of them. Personally, I like my Moore & Wright Micro 2000. It's as quick and easy to use as a caliper but with 1/1000th of a mm resolution and really good repeatability. I don't understand why they don't make spring loaded micrometers like that any more.

[@VintageMachinery]

+stefantrethan I am pretty sure that I have a Moore and Wright micrometer or something long those lines somewhere in the shop. I can't remember which tool it is but I know I have something.

[@matthewtroiano3024]

It would have taken me a while to figure out that I can pull apart my mic set to give it a good drop of oil. I probably would have used what ever is at hand like some motor oil. Probably better than nothing but not the best. Every time I use one of my mics I calibrate it just to make sure it is in standard. I mainly use my mics to measure cams, cranks and trans mission shafts in motor cycles at school.

[@VintageMachinery]

+Matthew Troiano I never have been afraid to take things apart. I loved Christmas morning as a kid because by dinner I would have taken everything apart to see how it worked. Of course, sometimes I had a bit of a problem getting everything back together again..... And I was quite sure that one time if I put that cross wire in my new set of Walkie Talkies that it would double the power, but instead I just released all of the "magic smoke" that makes those suckers work.....

[@derekcamp9764]

I'm just here to look at the pretty micrometers 4 years later

[@pyro854]

I have an old sears micrometer that I got second-hand and I can't figure out how to calibrate it. There is a slightly damaged flat head screw on the back end of the ... spindle? (sorry I don't know if that's the right term. Damn it Jim I'm a woodworker, not a machinist.) I'm thinking if I remove that screw I might be able to calibrate it but I would like to hear from someone that knows what they are talking about before I start screwing with it.

[@TiberiusStorm]

So the increments on the thimble that go to 25 are like dividing that 0.25 into a thousand??

[@VintageMachinery]

The thimble is threaded with a 40 Threads Per Inch pitch. Each turn of the thimble is 0.025".

[@TiberiusStorm]

Keith Rucker - VintageMachinery.org OK. I'm just trying to understand how it's dividing an inch. Measuring doesn't come easy to me but I have to learn this. So each inch is divided 40 times?

[@larryrobinson7492]

Very true but the way my mind works is thinking within .100. So by turning it once is 1/4 of that. Kinda like money (Quarters and dollars). Of course it's very simple since the thimble very clearly shows 25 when you get there.

[@RyanWeishalla]

I have some "digital" mikes that I use because I find it really tough to see the verneers. By digital, I mean the older non-electronic digitals. I did get a pair of safety goggles with bifocals, but it is still tough being far sighted.

[@VintageMachinery]

+ILGopher Some of the old "mechanical digital" micrometers are really cool. Brown and Sharpe made one that would just blow your mind - I should pick one of those up just for the coolness factor.

[@pblue2001]

Wish you would have mentioned the master block/standard needs to be calibrated so you can calibrate the micrometer.

[@57WillysCJ]

I learned to use a dial caliper and micrometers back in the 70s in physics class. Best thing I learned in high school. The one thing that is always told to people in machine shops when I started in 79. A micrometer is not a C clamp. Sounds funny until you have seen someone reefing one as tight as a clamp.

[@VintageMachinery]

+57WillysCJ One thing that you should never do is store your micrometer with the anvil tightened down. I meant to mention that in the video!

[@briansmith4932]

Be sure to eliminate any air that may be trapped between the micrometer face and the reference standard.

[@andyvan5692]

great lesson, but you missed some important points, for a beginner : 1) don't hold the metal body for too long (the heat of your hand expands the body, changing a reading). 2) if in ANY doubt about how tight to close the anvils, use the ratchet knob on the end, the click spring on the pawl will 'trip' at the right torque for measurement. 3) when making an inside measurement, you actually need to make two!, first is the part, using a bore guage, the second is to transfer the bore guage to an inside mic, (shortening for michrometer, slang used by mechanics) to record the reading, so be accurate, slow and steady, as you transfer from one to the other. 4) if your set is imperial (inches) CONVERT to metric at the END, as this imperial is decimal in nature (ie 1/100th inch =0.100 same as metric!!) so it is easily confused, so do it in fractions, then convert, plus you don't add an error in rounding for each round of measurements, ie if you have to sum readings, or compare them for tapers, or concentricity, do ONE system OR the other, NOT both, as it is too easy to confuse the two. 5) for point 4) above, WRITE down the system you use, OR do the same system for the same Job EVERY time, that way if you have a 'brain_fart' due to stress, family issues during a job, etc. you know that your 'fail safe' is to return to the same system, if you learn good habits they stay with you for LIFE.

[@thepandabusfitter202]

How tight should the micrometer be on the material?

[@VintageMachinery]

+The Panda Bus Fitter That is a hard thing to answer in words - it is more of a feel that you get with use. Most of your better micrometers will have a slip clutch on the tightening knob that will only allow you to tighten it so tight before it starts slipping. If you have never used a micrometer with one of these, probably the best way to learn this feel is to use one and after a bit of practice, you will know exactly how much pressure to use.

[@evanorner4979]

I looked for the high precision .0001 micrometer and I can’t find one

[@gregfaris6959]

Nice video, but don't you think this level of introduction should include mention of the torque-limiting ratchet?