SHOP TIPS #302 Calibrating a Fowler Micrometer tubalcain

howdy has tubal-cain again and I just got back from garage saling earlier today and I bought of all things another 2 inch micrometer or not that I don't have enough and those are just my stearic 2 inches but for five bucks couldn't turn it down but what is unique about this one and it's a Fowler brand that is made in Japan that's old enough to wear it's made in Japan we used to make fun of things that were made in Japan one of their kids but now we realize that most of the Japanese things are pretty high-quality anyway it's a Fowler and it came with a little adjusting wrench no standards but I have several standards but what is unique about this and at first I thought maybe it was just modified by the owner but we have reduced diameters here on the spindle in the anvil to allow you to get into a tight place and I'm sure it came from a factory because this has been ground and marked with with some numbers Control Number or whatever maybe was used for inspecting but I think this can be a nice little micrometer but it needs some work and let me show you what I'm going to do by the way this micrometer will read in tenths of a thousandths - as evidenced by the extra graduation the vernier graduations on the back of the barrel now when you buy a 2-inch micrometer or yeah just a 2-inch micrometer you're gonna find that you might get a round standard or one of these straight ones a cylindrical I prefer these but for what I'm going to do here because of the small anvils on here I'm gonna use a 1 inch gauge block and show you the the shortcoming of this particular micrometer so let me adjust that I'm holding this whoops in my Mauser micrometer here which is a quite handy way for especially for this demonstration so there we go we're right on and I have a ratchet stop here it has a lock as well need to back that off to get it out now let's get a close-up of the reading this micrometer was a few thousandths off when I first checked it and I are reserved it out using the little wrench that came with it and I think you all know how to do that but I'll run through that and in just a second here but what I don't like about this micrometer and I have had this happen to other micrometer but never a steric notice that the vertical line on the barrel is partially covered let me back it off here and you'll see that it now starts to appear I like to be able to see that line when it's zeroed out and it's hidden so using the micrometer as the gauge itself you can see that when I back it out all five six let's say seven thousands that graduation is clearly visible so I want to adjust this by 7 thousandths and in this case it's going to involve a little machining and it can be done by two methods but let me take this micrometer apart real quick and go over the parts in case you're not familiar with the parts and I have done this in another video a long time ago about micrometer z' micrometers have really five major parts but there's really more than that but I used to teach just the five parts to the high school kids so we got the frame the fixed anvil the spindle the barrel and the thimble and of course there's a thread in here and that's 40 threads per inch if you do the math you'll know why and in this case it also has the lock and the ratchet adjustment for to check the tightness and then there's there's some other parts here to this little threaded collar which has some notches on there can be tightened or loosened and that determines how tight the thread is and how hard you have to rotate this if it's too tight you can back this off a little bit if it's toulouse-lautrec you can turn it in and it it will tighten a little bit and if I can take that off real quickly you're going to see that there is a a split in there and that gets compressed almost like a collet and those are very precision threads you may or may not have made that adjustment on your micrometer was in the past and be sure and use a little oil on the thread and on the spindle when you assemble them and for best results use starett tool and an instrument oil catalog number 1620 what I intend to do to rectify this situation is check this up in the lathe and I'm going to machine off of the end here on the barrel I can get a point through here I'm going to machine six or seven thousandths off of the end here and I'm going to show you the setup and how I can get exactly five or six thousandths machined off of that and I'm not going to take this apart anymore but let me show you an alternate way of doing that as well I removed the satin chrome barrel and of course you look on the back side there's your vernier scale an alternate way of rectifying this situation would be to put this in a collet probably not a three jaw Chuck and machine just six thousandths off the end here where my finger is you could put it on the belt sander but I don't like that idea and you would not be in control of how much you're removing now how is this held onto a follower micrometer and that little hole there is used for zeroing out as you well know with the little spanner wrench but on this micrometer I don't think stirrups are made the same but when you install the barrel it simply pushes on and there's a friction type of springy copper device here that that gives you a tight fit now if you remove this this would slide on and off way too easily and you want this to be on there pretty firm so that's how they went about manufacturing this I'm not sure I like that it looks kind of cheap but I suppose it's good you can see these splits here a little bit better now that I've got the barrel off and what this tightening device will do it simply collapses the thread a little bit I'm going to put that back together off-camera because now that's not the way I intend to to fix this problem naturally on reassembly I lost the adjustment there so let me adjust it back to zero and that's going to be done with the little spanner and I showed you that hole a moment ago and I all I need to do is get the spanner in the hole if I can and then I'm going to rotate the thimble until it lines up right there so it's in adjustment but remember now I want to take off five six seven thousandth take the standard out so that that line shows up and it isn't covered or buried now that may not bother you but that that is a real problem for me to not be able to see that actually four thousandths would be enough which is really very little two or three or four hairs all right let's show you the setup for that in order to hold this on the Atlas lathe it would be ideal to hold it right here but in a collet but that's an odd size I don't have a collet that size so I'm going to hold it by the knurl but in order to hold it by the knurl I want to protect the neural and I'll do that with the piece of aluminum it could be copper or lead that's a little more than I would like to extend out of the chuck in order to machine this off but it's going to be such a light cut and such a minimal amount I don't believe I'm gonna have any problem with vibration I do not like the idea of chips getting in around this thread though so I believe I'll is just stuff that with cotton or paper or something before I put it in the Chuck and then I'll meet you over at the Atlas craftsman 12 inch lathe and I intend to take five or six thousandths off of the end of this thimble now let's take a look at the setup and this is my smaller three jaw Chuck which is quite an accurate one on the Atlas lathe and I've already gripped the work on the knurl protecting it again with the soft aluminum and I changed my strategy here instead of using cotton or paper in there which didn't work very well I've got a little piece of brass tubing hobby tubing about two inches long and I slid all the way in there and taped right here that'll protect the thread and allow me to blow that out to remove any debris or chips in the alors tool holder I have a facing tool I guess you would call it and it's squared up it's on center and if you'll notice here I've got the compound turned at 90 degrees and I've removed the backlash here I'm up against the work just barely just kissing the work locked the carriage right here zeroed out the collar here on the compound now when I turn it on I'm simply going to feed it in with the compound six thousandths now that's not very much and you might not even hardly see a shaving when that comes off you know what I just changed my mind again and I sure have been changing my mind quite a bit but look at the setup here I've got the little thick Noga indicator held on to the bed the flat bed of an Atlas lathe with that magnet I've got a mighty mag here and the plunger of the indicator is up against that and I'm $0 so I'm actually going to watch the indicator to move my six thousandths or rather than the collar here because I believe that would be more accurate but either way would work you know there's so many different ways of making a setup and that is one of them and here we go I've only got one shot at this and if I ruin it I'm out the $5 and that's it and I'm going to take a little jeweler file to that I feel a bit of a burner and I'll do that off of a camera but just a little bit of a a chamfer on there and it's so much easier to do that while it's still in the lay then at the bench sometimes the setup takes so much longer than the actual machining which was what five seconds so off comes the protection and I did blow this out already and I used a little file to take that burr off just a little jeweler's file and there wasn't much of a burn now I can take this off and I am assured that that thread is clean and of all things I got a little bit of adhesive here from that tape so I'm going to take some thinner and get that off use the steroid oil on the thread and assemble it and let's see how it looks it's just a little bit of a sidetrack here I bought this stare at Mike last summer at a flea market in Wisconsin for I think also five dollars but it's one of the nicer ones got the carbide and looks so nice and pristine doesn't it but when you flip it over well rather than flip it over I'm just going to turn the spindle here and you can see the tremendous corrosion from being improper improperly stored and I have cleaned that up it was rusty er when I got it and he can sit well it looked like that what you see up by the anvil when I bought it but those are pits and you can never get pits out you can only get the the high high spots out not the the soft the low spots other than that it's a good micrometer but you want to take care to always have that oiled so it doesn't get stuck in the frame and I've had that happen and also when storing micrometer yet you shouldn't store them with the anvils touching you should always back it off if you're not gonna use them for a long time and then everything should be lightly oiled or you'll end up with that alright back to the real thing now that's why I had to take that at he sell-off here because that would be very sticky let me go ahead and assemble this now I've already oiled it and and it goes and make sure that you have your your locks unlocked as you assemble a micrometer all right it's reassembled and calibrated and checked with the one-inch gauge block and it lines up nicely now remember that this is showing up on your monitor much larger than what it is in real life or that you can see with the naked eye now some are gonna say you didn't do anything different it's the it's the same or you didn't need to mess with it so I know I'm gonna get some arguments out of people but to me at this point it's a little bit easier to read to see that vertical line in other words at least three-quarters of the vertical line is exposed when it is zeroed out but even if you disagree with what I did and thought it was senseless or nonsensical at least you got a little idea what the micrometer looks like inside and then how to care for it how to lubricate it how to calibrate it and so on I hope you liked the video be sure and watch my 700 other videos this is a tubal-cain saying so long for now you

Channel: mrpete222

Views: 47,992

Rating: 4.930748 out of 5

Keywords: syarrett, brown & sharpe, mitutoyo, south bend lathe, bridgeport mill

Id: 9Z8WbJwlUcY

Length: 17min 50sec (1070 seconds)

Published: Sat May 07 2016