Micrometer Basics: Use, Care and Calibration

hello Keith record here bench machine org so over the last couple months I've had several requests from viewers and subscribers out there to make a little video on how to use micrometer the measurement tool that we machinist use to do all kinds of precision measurements and you know as a someone who's been doing machine shop work now for 25 years or so you know I guess I don't think much about you may not know how to use a micrometer because it's something they use on a daily basis but I do want to just take a few minutes and kind of go over basics on micrometer because there are many of you out there who don't have that experience and who are just learning and getting into this or maybe not even having you shop background at all and not having the experience at all using measurement tools so let's get in here and give you guys a basic training on how to use micrometers I went through all my machinist drawers and just kind of pulled out of a variety of different sizes shapes and types of a micrometer that I have that I use in my shop and as you can see here there is a wide variety of different types for different sizes and materials that you're measuring as well as for different functions that you're trying to do so the most basic type is just your regular micrometer that's used for measuring the distance between two areas so this would be used a lot on round material like on a lathe that can be used on a milling machine for measuring squares or just two parallel sides anything that you can slip this micrometer over to get a measurement it's an outside of micrometer is basically what this is they also make micro meters for doing inside measurements such as this one here so instead of going around it you pick it up and it expands and gets smaller when you turn the thimble right here and you can med do an inside measurement we've got one here this one here is for doing a depth so you would lay this across a top of something this would go down into a hole and again turning this in and out you can make that stem go up and down to measure the depth of a hole or something like that this is a hub micrometer it's made for getting into a really small area so if you have a hole and you're trying to measure the thickness of a hub you can get this down inside of a small hub a small area it works just like an outside micrometer but instead of having a big sweeping area that you can get something into is for slipping up inside of a hole in measuring here's another one this one is actually for doing a sheet metal where you can actually have a longer deeper reach to be able to get up in here and measure the thickness of a piece of sheet metal or a plate steel or something like that so micrometer is come in a lot of different sizes a lot of different shapes in for a lot of different functions and this is just an example of the few that I have if you start looking through some of the old catalogs from Scarritt and brown and sharp and some of the other companies you will see many many many types of micrometers that are used for different functions for today though we're going to be concentrating on just talking about the outside of micrometer caliper and a lot of what we talked about again it will apply to all these that are in here they're all basically going to work the same way they're going to be read the same way so what you see before you here is just a standard outside micrometer and I just picked one here for us to look at that's easy to pick up and handle this one particular one measures will range between six and seven inches most micrometers will measure a range of about 1 inch and travel and as you get into larger and larger sizes you actually have to have multiple micrometers to get those different measurements they do make some Universal ones that you can change these anvils out on the end for to be able to have basically one set to do a lot of different sizes but quite honestly you really want to have a dead kated micrometer when possible particularly with something you're going to be using a lot the adjustable ones you have to spend a little bit of time calibrating them each time you use them whereas these should stay in calibration pretty well between one use and the other and when you get ready to measure something that size you go grab the tool that you need and you get the job done so first off let's talk about the parts of the micrometer there are many parts and we just so the nomenclature that we're using everybody will understand so first you know this back part here this is just called the frame of the micrometer and that's basically the what everything is built on and again the size of this will depend on the size of that you're using down here on the bottom end the bearing surface this is called the anvil this part stays stationary it does not move and ideally I will say this ideally you will have micrometers of these anvils on both sides are made actually have carbide on them so they do not wear very much many of them are just steel and if you use them a lot over and over and over again particularly if you're like doing inspection worker where you're using that that micrometer a lot they will wear over time and they can get go bad on you so if you have a carbide faced micrometer it tends to hold up very well this particular one here is not carbide face but put this one in here just for second you see the changing color down here this from this carbide face and particularly on your smaller ones this is up zero to one inch this is probably one of the ones that I use more than any other size and because of that I really won't carve out on it the larger ones I don't use as much so I don't consider the carbide to be as important for me at least how I'm using them in my shop so the micrometer is a precision measurement tool and depending on the type of micrometer that you have it would be capable of either measuring something down to a thousandth of an inch or in some cases to a ten thousandth of an inch most are just going to measure to a thousands but you may actually have some that we go to ten thousand this particular one we have here measures to a thousandth of an inch and you read that down here on this scale and we're going to talk about exactly how to read that just to but before we get into that let's talk about how the micrometer actually works so again we were talking about the parts with the frame the anvil this is a spindle here this is called the sleeve that has the numbers on it and then the thimble is up here this is the part that's going to rotate and let's zoom in a little bit closer so you can maybe see exactly what's going on right here so again the sleeve stays stationary the thimble rotates around it and as you turn this it's basically got a screw thread in here and it's going to move this spindle in and out so most of micrometers actually the way this works is there's actually a thread inside of this so you got a thread in here and the thimble has a nut in it and the thread in there is at a 40 pitch forty threads per inch so you have to turn the spindle 40 times to make it move one inch in or out and so by doing that so you do the math 140th of an inch is a 25,000 okay and if you look on here there are lines in here and each one of these lines look show 25,000 and also if you look on the thimble it's March so we've got 0 24 25 so when I turn this out you can see the numbers each one of those numbers represents 1,000 I come around to my 0 again and you can see there's another line up underneath there so each one of these lines represents 25 thousands now to read a micrometer it requires doing a little bit of math and some people don't like doing math but that's what it requires at least to read this type of micrometer they do make digital micrometer so it will give you a digital readout I personally like the mechanical ones just like this because the batteries never go dead they always work you don't have to worry about whether where you set your zero at on it but right now when we look at this well the first thing you have to know when you're to read a micrometer is what you're starting out with so this one measures six to seven inches so we always know that we're going to be six inches plus whatever we get down here and if you look in here again each one of the small lines represents 25 thousands the large lines that have a number on them the 1/2 that's going to be hundred thousands so you got a hundred thousands and 125 150 175 200 thousands right now the way this rock comet is reading is we're on two hundred and twenty five thousand so if we had something that measured right there it'd be six inches two hundred twenty-five thousand we have to add all this together so we know the start with is six inches we look on here the first number here we're on two that's going to be your tenths of an inch and then you go down here and you look how many increments are there we're on the first increment that's twenty five and we're on zero that's 25 if we rotate this around just to right there to the five mark so now we're at six inches 225 plus five so be 230 thousands so again you have to do some math add these together it's not hard math but it is math you have to do if you're first getting started with using micrometer I would recommend that you write these numbers down it will kind of help you add them up as you get more and more experience you will find that you can do this math in your head fairly easily so again let's just we'll just kind of pick a random spot on here you know here we go right now we read this we're at we're at 300 we got 25 we're at 50 okay and then we so we're at 350 thousands and we look on here we're between the 20 and the 21s which one do you go with well until you cross the 21 it's going to be 20 thousands now in this case is somewhere in between but if you're not writing down a measurement this is going to be three hundred and seventy thousand says what it's going to read so 350 plus 20 this will be three hundred and seventy thousands it's quite simple to read a micrometer and it just takes a little bit of practice don't be scared of it I've swapped out micrometers here and I've got one that's a little bit different this one here is a one to two inch micrometer and as far as reading to the thousandth of an inch it reads exactly like the one we just showed you and I've got it set on the same measurement basically that we had the other one which is a 1.37 oh the difference so with this micrometer is this micrometer is a has a vernier scale on it that will allow you to read this measurement down to the ten thousandth of an inch so if you look on here if we rotate this around you can see this scale across the top here let's make sure we get that in focus there we go so if you look here there's a vernier scale right through here and what you do the way you read this is is you you look at the lines over here the long lines and there are numbers out here and each one of those numbers is a ten thousandth of an inch and what you want to do is you want to find the line that lines up with one of the marks on your thousands dot and you're not really paying any attention to what number is over here you're just trying to find the one that most closely matches and lines up so let's go back over here and let's put it back about where it was and we roll this around and we look and right here this line lines up with this line and that is six ten thousandths of an inch so in this case the measurement is going to be one-inch 370,000 s and six tenths or to read that in decimal be 1.3 706 so to give you another example here and also to show you of micrometer that reads it's a little bit differently on the ten thousandths this is a steric number 221 this is a probably my favorite micrometer this one this is zero to one inch they only make this model in a 0 to 1 inch unfortunately I wish they had it for other sizes as well but anyway let's look at it here so we were measuring in here and you know I come in here and we measure that and I'm going to show you how to write this down so we can add this up so we start out with a 700 so it's 0.7 zero-zero we would read there okay we look at the next line we're past the first line excuse me 0.025 thousands okay and then we read what's on the micrometer and we're at 21,000 0.02 1 so we'll add all that together so we're 746 thousands now on this micrometer to read to the ten thousands what you do is it actually has a little spring-loaded barrel in here and you just move this over until you line up the mark here with the line like such and then you read your ten thousandths over here on the scale so and this is kind of hard to show but it's right over here you see which one so let me get that back on line right there and we're a little over one ten-thousandth so we're going to call that one ten thousand so the actual number here will be zero point seven four six and one so now that you know the basics on how to use micrometer one thing that you need to also understand is how to calibrate your micrometer to make sure that you're getting an accurate measurement they can come out of calibration from time to time and they're really quite easy to to get set so that you're getting a good accurate measurement so with a zero to one inch micrometer the way you calibrated is simple you just bring it in all the way down into it dead-ends on the anvil and the spindle come together and they should line right up and if you look right here you make sure we these faces are clean in which you can clean your faces is just to take a piece of paper put it in between them bring it down and just pull the paper out you don't want to have a whole lot of tension on them you can see there's a little bit of grime in there so now let's go back over here and it's lining up right on zero just exactly what we want okay so just that little bit of grime on there was actually making it off by several ten thousandths of an inch but we want the zero to line up perfectly with the line right there if it is off a little bit it's quite easy to fix when you buy a micrometer they usually come with a micrometer wrench like this right here and if you look on the back of this micrometer there's a hole you take this little wrench you put it into that hole and and I'm not going to actually do it on this one but you just turn the barrel until you get it lined up exactly right there you can go either way with it forward or backwards and you can this will actually turn in there and you get it where it's lined up exactly zero this cap micrometer is in good shape it's ready to go and that's how you start with a zero to one you just go all the way down to the bottom so you might ask well how does that work if you got a one to two inch micrometer because you can't bring it all the way down so let's take this down to zero right there and notice we got a gap in here so we've got to put something in there to measure and again when you buy micrometer you buy new micrometer it usually comes with a standard to check it with here's the zero to one inch all right one inch standard and you just come in here and we measure this just like we would if we were measuring it we want to make sure that it reads exactly zero and it does so that micrometer is in calibration again if it was off you would take it down to zero you can use this little thimble lock right here to lock your your spindle or spindle lock and now you can use the wrench and again adjust that got it locked there we go when you go up to the larger ones again you have different standards this is a two inch standard this is a two to three inch micrometer I'll bring this down to zero and measure it there we go right on the money another maintenance thing you can do two micrometers from time to time is you can lubricate these to make them work a little bit better so what you're looking at here this is a zero to 1 inch brown and sharp micrometer this was actually a gift to me from one of my viewers on my channel that took an old one and repainted it in this case he painted it up red he want to be a little bit different and there's nothing wrong with micrometer but when I got it I noticed that this barrel on this is just a little bit stiff it's a little bit stiffer for my liking so if that's the case you know don't be afraid to take one of these things apart and you just basically pull it all the way out okay you can actually see the thread in here that a 40 pitch thread and I've just got some lightweight tool here and I'm just going to put a little drop of oil down here not much just a little bit starik makes a really good tool oil that you can purchase that I really like using on my find measurement tools there we go and we'll screw it back in and just that little bit of oil I can already tell there's a difference in how how this a micrometer is working you didn't use an oil you want to if you don't have a starett or use a real lightweight machine off of this you don't want to get too much in there either just enough to lubricate it so there you go guys a basic training on how to use and care for your micrometers calibration and everything included it's not that difficult my advice to you if you're you if you're just getting started using micrometers and just want to get good at it get out and just start measuring things in the shop get a pen and paper write it down it's not very difficult it's fairly easy to go through but with some practice a little bit of experience you can quickly make very accurate measurements down to a thousandth or even ten thousandth of an inch using a good quality micrometer thanks for watching

Channel: Keith Rucker - VintageMachinery.org

Views: 102,386

Rating: 4.9376678 out of 5

Keywords: Machine Shop, Machinist, Lathe, Milling Machine, Restoration, Vintage Machinery, mrpete222, Mr. Pete, Tublican, Keith Fenner, Turn wright, Adam Booth, Abom79, Tom Lipton, Ox Tools, oxtoolco, myfordboy, Jody Collier, Starrett, Brown & Sharpe, Tips, Tutorial, Tricks, Micrometer (Invention)

Id: VU23AIlU0Cg

Length: 20min 30sec (1230 seconds)

Published: Tue Sep 01 2015