Read a dial indicator (dial gauge)

hello everyone welcome to my math class in this video I'll show you how to read a dial indicator or a dial gauge with a dial gauge you can measure run out run out means you can check rotating parts for straightness such as a neck so you can check your brake rotors for straightness or your wheel you can check for straightness your the chalk on your drill or drill press or you can measure run out on your lathe it's important that these parts be rotating straight measurements will be covered on another video on this one what I'm covering is how to read one how to read this dial gauge so other than this one is mounted on a stand and has a magnetic base it's functional part is its diodes it's got two dials on it with two needles the outer dial rotate and the other one is fixed I make sense of the numbers and I will get you a close-up in a sec the other functional part is this probe here that has a one inch truth I know this is a one inch stroke because I can just very simply measure it like so it's a little more than one inch but that little bit is not important I'll explain in a sec as this probe is pushes in you can also see that it's extending at the top and there and it's key to reading a dial indicator and to make sense out of those numbers is that this one inch of straight line travel corresponds to an exact amount of rotation on the dial inside the gauge there's a bunch of gears where to be exact there is a rack and pinion mechanism inside so there's a bunch of gears and the ratio is set and is constant for those gears so a certain amount of straight-line motion will consistently always cause the same amount of rotation on the needles so let's key to understanding this another one another thing and this is where your model may be different but you can make sense of the numbers themselves that if you just measure this one inch you need to know what their gearing ratio inside is you need to know how many full turns does the main needle take that corresponds to this one inch of straight travel the data just set it to zero like so and count the number of full turns the partial turn don't worry about it that there's going to be a partial turn but that partial turn is just there so you can set your zero without hitting a stop and in the gearing mechanism so let's count the number of full turns this is one full turn they're two full turns three four five six full turns seven eight nine full turns and ten full turns and other than that there's an extra half a turn but that is for really for setup and there's also a little bit of play inside the gears so one inch means ten full turns on the dial so that means that one turn on the dial corresponds to one tenth of an inch of straight-line motion okay because it takes ten full turns to cover the inch therefore one full turn like so that's one tenth of an inch okay that's important I'm gonna write this one down here so one full turn equals I'm going to write fraction as well as decimal one tenth of an inch that's those two whiskers that's how you write inches and 0.1 so one full turn is one tenth of an inch now another thing is take a look at the numbers let's start there the big numbers on the sorry the big numbers on the outside dial read zero and then 10 and 90 20 with 80 30 with 70 40 with 60 50 50 and you can see the rest of the numbers now the numbers on the smaller dial here that doesn't move it reads zero and then it says 0.5 yes there is a point in front of the five and then it reads 0.1 0.6 0.2 0.7 0.3 0.8 0.9 point four and we are back to zero with 0.5 I read it counterclockwise because the smaller needle rotates oops rotates counterclockwise like that okay so let me explain the meaning of the those small numbers on the smaller on the smaller daya so let me set it to zero there like I said it takes ten turns to travel one inch so I'm going to make one full rotation on the main needle on the big needle there it took one full rotation and you can see that the little needle is pointing at point one that means that on the probe zero point one inch of travel has been taken zero point two inches is the advance zero point three no sorry guys it doesn't have a quarter range or something but quarter-inch would be somewhere the our this 0.25 0.3 0.4 inches is there after five full turns on the main needle the smaller needle is pointing again at 0 and 0.5 and then you read the little dial as 0.6 0.7 now the only way you can tell whether it's 0.2 or 0.7 is you look at the probe here and take a visual look how much has it traveled 0.2 would be here and 0.7 is somewhere here that's really the only way to know and and if you start actually at 0 0 like there when both needles are pointing at 0 you're gonna have to count the full turns and go 1 2 3 full turns for 5 full turns and then 6 7 so you gonna have to keep it in mind where you were at the beginning and after 7 turns you have traveled 0.7 inches forward okay okay that's how to make sense of the little dial or the numbers on the little tire and the little needle now the big one is somewhat simpler and at this point I'm gonna tell you it's extremely finicky so if I put my clipboard or pen or something on the table it's gonna make the needle move see I'm okay or here is my clipboard if I just lift it up or whatever it's making the needle move so please work with me on this one I'm going to try my best to set it to zero but just just be patient there okay the main needle the big needle is at zero now like I said one full turn is one tenth of an inch you can still see it in the background there if you count the number of hair lines on the main dial on the big outside dial here you can see one two three four the fifth one is a little longer six seven eight nine ten and 11 12 15 20 of these lines 30 going around 40 50 70 80 80s here 90 of these lines 95 99 and what comes after 99 100 the outer dial has 100 parts so that means that the one full turn the one inch has been divided into 100 finer parts the question is what amount is 100 of a tenth one full turn is the tenth and we have 100 nicely evenly spaced lines to cover that one-tenth so I'm just going to pull this one a little bit aside here and set it back to zero again or so getting there there so to make it fast each hair line on the outer dial is one thousandth of an inch so I'm going to just write one over a thousand inches in fractional form at there and I'm gonna do it with my clipboard in the air okay so I can set it back to zero or in decimal format its 0.001 there if I don't hit anything 0.001 and that number you can see printed by the manufacturer they're about on the dial indicator to tell you that the smallest increment is one thousandth of an inch and and any feet are 0.01 inch - 1.0 inch meaning that after 10 full turns you will be reading a one inch of travel okay so every increment is one thousandth of an inch consequently if I set it to say that number we have traveled four thousandth of an inch forward please note that the gearing is also moving the little needle counterclockwise so four thousand the next number is say 6000 there and how these look like in fractional form at ease this one is six over a thousand or in decimal format 0.006 try not to hit anything there so far so good now we're going to get to the number 10 there 10 you can write very simply in fractional form at ten thousandth so far we traveled ten thousandth of an inch or you can simplify it by crossing at two zeros simplify this fraction like so and you can read it as one hundredth of an inch ten hundredths or one sorry ten thousand or one hundred of an inch is the same thing and in decimal format this looks like there there is ten thousandth of an inch or I can cross that the last zero and just go zero point zero one one hundredth of an inch now next sheet of paper and let's keep going other way so that number would be there there we go that number would be kind of close to almost there at seventeen thousandth of an inch and you cannot simplify that fraction at just 17 thousandth of an inch okay that one is Twenty twenty one thousandth of an inch let's go up to thirty there they're about 30 and how you write that number is again 30 over a thousand to make it look like oops I kicked it 30 over a thousand there we're back in action 30 over a thousand or again you can cross that to zeroes and go three hundredths of an inch or in decimal form and just go 0.03 that's how it looks like 0.03 or 300 tamo of an inch now as we go around I'm gonna make it just go around this way you can please notice that the little needle is also moving forward as they are geared together with the big needle so that would be seven hundredths of an inch eight hundredths of an inch nine hundredths of an inch and that one is 98 thousandth of an inch and if we get back to zero ninety eight thousandth of an inch and that one is one hundred thousandth of an inch one hundred over a thousand in fractional form at like so one hundred over a thousand now from this fraction you can cross at two zeros and well to from the numerator and two from the denominator and then we're back to one over ten or 0.1 one tenth of an inch in a decimal format like so now we're not done because what happens if you have that measurement there now this one is for thousandth of an inch if the little indicator then and down at the bottom is pointing close to the zero but it isn't it's pointing close to the point one point six I know we only traveled one turn so it's going to be 0.1 so now we need to add one sorry one tenth place it where is it one tenth of an inch plus let me just set it back to four just give it that or back to four so we have to add one over ten plus four over a thousand they're in fractional form at one over ten plus four over a thousand and that's why I used the fraction of format with all of its zeros please remember that one over ten is the same as a 100 over a thousand and one hundred thousand plus four thousand is easy to add because 100,000 plus four thousand is 104 thousandth of an inch that's what you're looking at and in a decimal format it is written like so 0.104 this is 104 thousandth of an inch that's what you're looking at let's take another one let's go forward how about that one this one is 110 thousandth of an inch which looks like I'm going to use sheet 110 over a thousand in fractional format looks like that I know it's out of focus but I don't want to hit anything on the table and if I cross that the last two zeros is the same as 11 hundredths of an inch so my policy or what what I do with the with this dial gauge I read everything in a thousand and if I can I simplify the fraction but not really because it's R because it's more meaningful or easier to take a reading in just a thousand format here 110 over a thousand is the same as 11 over a hundred and eleven over 100 in the decimal format looks like that zero point eleven okay last two measurement because it's been taking a long time there it's pointing at 25 that means that so far we've traveled one full turn that's 100,000 plus 25 so that's 125,000 you can just read it like that I'm going to spin it ahead so we traveled two full turns how about 3 full turns um sorry guys alright if I set it there just a little bit back like so I'm gonna reset the camera because there that's a better angle so on the little dial there you're going to start with that one from the zero it went to the point one point two point three and it's showing you that it's a little past the point three the three tenth of an inch let me just pull it sideways so I can smuggle in my clipboard air to your right side of your view so my first number will be zero point three I'm going to ride up on land 0.3 there or 300,000 there three hundred over a thousand because 3 full turns are three hundred part okay and every part is a thousand so to get back to where were we okay let's it's so touchy okay let's go with that number okay so so far it's point three that's a given 3 full turns and then it's pointing at 13 so what I need to do is add 13,000 thirteen thousand to the three hundred thousand three hundred plus 13 is three hundred and thirteen over a thousand so I'm gonna write three hundred and thirteen thousandth of an inch just like so or in decimal format I'm going to just write three one three there so zero point three one three that's what you're kind of looking at there in the upper part of the picture okay that's how you work it out with the fractions and the decimals again you don't have to take a look at the needle indicating the full turns as well as combining it with the amount of turned taken by the main needle there and it's very finicky so when you take measurements on axles or or check your brake rotors or wheel for run-out it's gonna be finicky and nerve-wracking and it's gonna need a lot of patience okay in my next video I'll show you how to check an axle for run-out thanks for watching

Channel: apprenticemath

Views: 706,469

Rating: 4.7224197 out of 5

Keywords: math, trades, apprenticeship, AST, commercial vehicle, axle, shaft, brake rotor, wheel, motorcycle, motorbike, bike, bicycle, dirt bike, enduro, cross, motocross, machinist, technician, technologist, dial indicator, dial gage, dial gauge, run-out, out-of-round, race bike, racing, track, mountain bike, Dial, Indicator

Id: TrRcEg0NB9A

Length: 20min 45sec (1245 seconds)

Published: Tue Jun 18 2013