How to use a Magnetic Base Dial Indicator

Hello, my name is John Kelly, and this is the  WeberAuto YouTube channel. In this episode we   will look at the precision measuring tools  that we use in my shop classes specifically   dial indicators I have four different types of dial  indicators here with four different mounting bases   and levels of precision and I'm going to take  you through the operation and care of each one   of these dial indicators now my favorite dial  indicator that I use all the time in my shop   classes is this magnetic mount dial indicator so  there are two different types of the magnetic mount   dial indicators this one has a base that adjusts  to the shape order of whatever car part you want   to stick it to magnetically this one just has  a flat base and must be stuck to something that   is flat which on an automobile there's not a lot  of flat steel parts that you can stick a magnet   to so let's take a look at this one this is the  this is from Snap-On it's part number GA3645   they are expensive but it's a wonderful kit I've  had this one for going on eight years now and it   works just as well now as it did when I purchased  it but one of the reasons it works as well is I   treat it with care now you'll notice when I  opened the box it has a couple of pieces of   foam in here the little piece of foam goes over  the dial indicator itself the rest of these go   or the other piece of foam goes over the rest of  the parts in that box and that keeps things from   rattling around and coming out of place when  you're carrying the box around so don't set   these pieces of foam in oil or throw them away or  anything because I need them put back in the box   when you're done with it all right  in the box itself, we have two clamps that go   on two different rods, each of these rods has a  different diameter so this is a large diameter   rod this is a small diameter rod and there is a  large diameter clamp that's going to go on this   one and a small diameter clamp that goes on this  one sometimes my students will swap those around   or try to swap them around and wonder why they're  it's not fitting or working and that's why there   are two different sizes okay so let's set this  off to the side for a moment and let's just   look at the magnetic base itself the magnetic  base has a lock on one side if we unlock that   by pulling this lever back it has all of these  little fingers that will stick out the bottom   so I always unlock it to begin with and stick  all these little fingers down and out and then   these fingers can take the shape of whatever  part you want to stick the magnet to so for   example over here on this vise we have a rounded  end here I can just stick that right to it and it   can be at any angle that I want to get it set  just right and then you use the locking lever   here on the end to lock it in place and hold it  tight so that's one of the things I really like   about this magnetic base dial indicator is  this base that fits to the shape of whatever   part you want to stick it to alright there's  a magnet up inside of these two rows of little   fingers that magnets sometimes comes or wants  to come out when you push the little   fingers in if that happens just push back down  on the magnet and pull the little fingers back back were three where they go alright let's see  how we hook up the rest of the parts of the dial   indicator so I'm just going to stick this on the  bench right here I've got a stainless steel top   so it doesn't stick really well but I'm going  to lock it in place anyway and then I've got   the clamp that goes on the large diameter shaft  here so I'm going to put that on here putting   the clamp on the small diameter shaft so there's  a hole right here on the other side of the clamp   and that's where this small rod is going to come  in just like that and we can position that at any   angle height and length that we want so I'm just  going to put it like right here and then we just   lightly with our thumb and finger tighten that  down enough that this won't move any more versus   the large rod we do not put pliers on there or  give it a whole bunch of power in from muscles   or whatever else you might be using to tighten  that up this is just a plastic knob on the end   here and it will break and I have had students  break these trying to tighten it down tighter   than it needed to be it's just a small amount of  clamping force is all it needs to hold it in place   okay this other clamp here for the small rod can  be put on two ways we can have the thumb screw   on one side or we can flip it around and have it  on the other side and of course, you can rotate it   but that also puts the clamp at the bottom or the  top and depending on what you're trying to measure   you may want to have it at the top or the bottom  just for clearance reasons so this clamp is going   to hold our dial indicator in place the dial  indicator here is a very delicate very precise   dial indicator if we look in at the face of this  dial indicator each of the little tiny marks the   smallest marks in there is half of one thousandth  of an inch or as it shows right there 0.0005   inches that's half of one-thousandth of  an inch the marks that are just slightly larger   are one-thousandth of an inch 0.001 inches and then the larger marks that are   numbered are in five-thousandths of an inch  increments or a 0.005 inches   now the plunger on this dial indicator here has a  travel length of one inch so we can measure up to   one inch of movement normally though in manual  drivetrain and automatic transmission classes   we will only be measuring very small movements  five, ten, fifteen, twenty, maybe fifty, to a hundred   thousandths of an inch of movement but this dial  indicator goes from zero to 50 thousandths of an   inch or point zero five inches in one revolution  of the needle on the dial so in one inch of travel   that is going to spend twenty times two times  for each 100 thousandths of an inch there are   ten one hundred thousandth of an inch in one  inch so the needle will spend twenty times in   one inch there's a little counter right there  that'll tell you how many hundred thousandths   of an inch you have measured up to that point all  right these dial indicators are very delicate if   you accidentally drop one of these dial indicators  you can ruin it and these are not your cheap $12   Harbor Freight dial indicators, these are jeweled  dial indicators which means they have Ruby bearing   caps and bearings in them for precision work  precision measuring work that should last the   lifetime your lifetime if the tool is taken  care of properly but if you drop this thing   it can be damaged quite easily so be very careful  when you're putting this dial indicator into the   clamp on the magnetic base or whatever base you're  connecting it to because it once again if you drop   it, it can be damaged and if you do drop it in  one of my classes please let me know so that I   can see if it's damaged and get it repaired now  there's a base right here on the dial indicator   that we can clamp to lightly clamp to and hold it  in place so that's one way to clamp it here on the   dial indicator base so if I bring this clamp up  and it has the hole right there I'm just going   to stick the dial indicator through so I'm going  to stick it through far enough that some of that   sleeve is sticking through at the bottom there  and then I'm just going to lightly clamp that down and now we've got the magnetic base dial  indicator the large rod with the large   clamp the small rod with the small clamp and  the dial indicator itself all mounted in place   now on the face of the dial indicator here we've  got this red outer dial here and we can zero the   dial indicator by moving this outer face one  way or the other sometimes you want to zero   it and start at zero and move one direction  or the other as you take a measurement with   the dial indicator cater other times you'll  take what's called a total indicated reading   which you won't need to zero it you'll just see  where it is before you take the measurement and   see how many thousands of an inch it moved  after the measurement and just do the math   in your head and come up with a measurement but  for beginning users of dial indicators, it helps   to put it on zero there's a little thumb screw  right here on the side of the dial indicator   that if you lightly snug that down it will lock  the red ring from turning but don't put a pair   of pliers on there don't use excessive force  because you'll damage the dial indicator I'm   going to loosen the base clamp here the small  clamp a little bit and let's look at the tip   here of this dial indicator so the tip of this  dial indicator can be removed you just unscrew it so there's the tip right there and the reason you  would want to take that tip out is if maybe you   would want to put a different tip on and so if  in my classes you remove this tip then I would   like you to take that tip and set it inside of  the plastic box that the dial indicator comes   in so that we don't lose it so just set it in  there so that we don't lose it in my   dial indicator kits here I have some extensions  right here these are tip extensions that can be   installed we can each of these are one inch in  length and so we can extend the length of the   dial indicator plunger one inch at a time and  then there these are different tips that would   go on the end of those extensions they also sell  very long extensions this one I have not measured   but it looks like it's maybe eight inches long  but if you needed a big long extension to go   on your dial indicator then you can buy one of  these and screw it in place they   should always just be screwed in by hand and  never tightened with a pair of pliers because   you can damage the inside of the dial indicator  if you do that let me remove that all right the   next thing I want to show you is there is a what's  called a contact point kit or set its part number   25R from Starrett and inside of this kit it  has a variety of different extensions different   tips I'm saying not extensions it has a variety of  different tips that can go on the bottom of that   dial indicator so we have some flat has some  flat tips rounded tips pointed tips different   shapes and sizes inside here there's just a real  pointed tip and then not part of this kit there's   also a roller tip that you can buy if you're  measuring something like tire run out on the   vehicle sometimes having a roller tip rather  than a flat tip or a rounded tip can come in   handy so these tips I keep in these boxes in my  precision measuring toolbox and we can get those   out as necessary in my classes I'm going to screw  the tip back on so let me give you an example of   using this magnetic base dial indicator to measure  something okay right here I have a cutaway of a   front axle of a Toyota Tundra and I'm going to  use this dial indicator to come in and measure   the backlash on one tooth of this dial indicator  so I'm going to take the magnetic base unlock   all those fingers extend them to the length their  maximum length try to find something that we can   stick the dial indicator to so here's a bracket  right here I'm just going to stick it right there   and lock it in place so now we've got a good  solid connection to this whole assembly and now   I'm going to use this the large clamp to loosen up  the small rod and get it positioned to where I can   come in and get the plunger on one of the teeth  of the ring gear here so I'm going to pre-position   the small rod close to where I need it to be  then I'm going to use the small clamp and the dial indicator and I'm going to use the small  clamp and position the dial indicator over one   of the teeth needs to be at a right angle with the  tooth it can be a little bit tricky it's going to   try your patience to get that setup but there it  is right there it's sitting on a tooth at a right   angle I'm going to snug down both clamps just like that  so let me get this position a little better so   you can see what we've got right there okay so  I've got the base attached to the large rod large   clamp small rod small clamp dial indicator and  then the plunger has some travel in it it's the   plungers poking up just a little bit right here  indicating that we've loaded the dial indicator   if this was sitting down flat that means that  we're not touching the part that we want to   measure the or take a measurement with and so  we would need to move the dial indicator down   more if this upper plunger was not extended  like it is now if we look closely in at the   tooth on the dial indicator there you can see that  it's at a right angle with the or whatever it is   you're measuring and the important thing is when  you're taking a measurement with a dial indicator   it's very important that that plunger be it at  a right angle at 90 degree angle with whatever   you're measuring if you get it tilted from one  side to the other your measurement will be wrong   and it'll be too small anything that puts it on  an angle will cause that measurement to be too   small so let's take this backlash measurement  and now I'm going to come in and just move the   ring gear back and forth with my finger so we  went from 0 to about 7 thousandths of an inch   counterclockwise which tells us we've got  7 thousandths of an inch backlash and you   would have to look up the specification on the  vehicle that you're measuring the backlash on to   see if that is within specification so that's the  backlash just on one tooth and there are close to   40 teeth on a typical ring gear okay so that is  using a magnetic base dial indicator when you're   finished using the magnetic base dial indicator  I want you to disconnect it disconnect the base   and if you're going to use it again in my class  that very day then set it very carefully back in   the box with the making sure that the plunger  is not being compressed or laying on anything   solid if you are done using the dial indicator  I need it disassembled and boxed back up with the   foam put back in place just like you found  it so that's a magnetic base dial indicator

Channel: WeberAuto

Views: 46,793

Rating: 4.7202072 out of 5

Keywords: dial indicator, Central Tools and Equipment, snap-on, NACAT, starrett, Weber State University, Precision, Snap-On, CAT, CCAR, backlash measurement, John D. Kelly, Ring and pinion setup, Starrett, Weber State Automotive, STEM, WSU, ASE, Precision Measurements, Guy in wheelchair, NATEF, Measurements, Professor

Id: rUMPFg3OWK8

Length: 21min 38sec (1298 seconds)

Published: Thu Sep 07 2017