Questions & Answers

Questions posed by customers and readers, answered to the best of our ability.
Do you have a question?

• Bestest indicator
• B&S dial caliper
• Co-Ax dial indicator
• Compac dial bore gage
• Correx gram force gage (tension gauge) see page 10
• Dial caliper
• Dial caliper gage (Intertest)
• Dial and digital indicators
• Etalon micrometer
• Groove micrometer
• Interapid test indicator
• Measuring rods - micrometer and caliper standards
• Micrometers
• Micrometer lapping
• Mitutoyo dial calipers
• Mitutoyo digimatic calipers
• Mitutoyo USB and SPC output
• Peacock
• Pin Gauges
• Screw thread micrometers
• Starrett dial calipers
• Starrett dial indicator
• Starret Last Word indicator
• Tesa Cal digital caliper
• Test indicators
• more information on our Do-It-Yourself page
  
   

Mitutoyo dial calipers

Q: Which screws should I order for the slider stop? I need to replace the slider stop, the black plastic piece at the end of the caliper beam. It fell out and I lost it.

A: Slider stops do not use screws. The plastic stop has two pegs which fit into the holes that look like they would be for screws. This is the reason the slider stop fell out in the first place.

Q: I need a thumb roller hook for a Mitutoyo caliper model 500-351.Your parts list shows that I need thumb roller hook 145120 that is discontinued without replacement. The parts list also shows thumb roller hook P/N 141941. Will this work or am I screwed?

A: The different thumb rollers are not interchangeable due to some subtle size differences. Unfortunately the designers at Mitutoyo never take this into consideration when they come up with model changes. You are screwed.

Q: I have an old model Mitutoyo caliper and I'm not sure if I can use the dial from a new model. Will this cause problems?

A: You can use a new dial, assuming it is the same diameter and has the same numerical configuration, but if someone down the line tries to order parts they may inadvertently think they have the wrong model number. If you change out a dial, be sure to write the correct model number somewhere conspicuous on the calipers to avoid problems.

Q: Do Mitutoyo calipers get oiled when reassembled?

A: There is no oil in the movement at all. The beams are often coated with a thin film of oil just to keep them corrosion free. It is best to remove the oil on the beam, if you notice any, with a cloth and a bit of alcohol. Do not allow any liquids to enter the movement.
 

Dial and Digital Indicator

Q: One of my gauges (Kafer digital indicator) has developed a binding in the spindle.  I have confirmed it is not the external linkage that is binding but rather the vertical shaft that runs through the gauge.  The spindle will move but not without some “coaxing”. Before I try to add some lubricant to the spindle, I wanted to check with you to see if this is the recommended procedure.

A: The spindle should never require lubrication. In fact, when we repair them we make certain to clean them thoroughly so that no grease, oil or grime remain. It may be a better idea to apply a few drops of alcohol to the spindle. This may clean it, if dirt is the issue. Mind you, be careful to keep any liquid away from the electronics. There can be several other reasons for the binding, not least of which is that the spindle has become slightly bent. You may want to have it serviced if the cleaning doesn't get any results.

• For additional information on dial indicators, refer to page 139.

Q: My one-inch travel indicator is off by .025" Can this be fixed or adjusted?

A: It is very unlikely that anything mechanical has given you such an error. I would take a close look at your set-up. For one thing: your spindle has to be perpendicular to the measuring surface. Even a slight angle will result in noticeable cumulative errors.

Q: Why is it that sometimes spare parts listed on invoices have a discount and sometimes not?

A: If we have to replace a part during repair, you will notice a 20% discount in all but a very few instances. However, if we have to replace a part which is missing to begin with, you will be charged full price.

 

Starrett digital calipers

Q: We have a Starrett digital dial indicator 2600-1. One of the digital digits is missing the left hand vertical element. Took it apart to clean the contacts. One of the contact springs bounced out of my tweezers. Can't locate it. Can I buy a replacement/or set of spring(s)? Seems pretty accurate and I only paid 65 bucks for it. Worth repairing if cleaning the contacts didn't work?

A: I think the best thing to do is go directly to Starrett for this information. They may even sell directly to you (although they won't sell to us). 1-978-249-3551 We have no experience with the Starrett digital indicators, so can't offer any suggestions. Good luck!

Calibration

Q: I was looking for an industrial standard to reference in my calibration program and happened across your very useful site. You have very specific standards for verifying the condition of, for example, dial calipers @ .001 up to 4", .0015" up to 8", etc. Where do you get these figures? Is this from a commonly available standard? Can you tell me what the standards are and where to get them?

A: Each manufacturer publishes these tolerances in their catalogs. You could also call them up for the information. Sometimes it's also included in the literature that accompanies new gages.

A recent customer was unhappy because she just bought an 8" dial caliper from us and it's off by almost .001" at 4 inches. Although the manufacturer would claim that this is within allowable tolerance, we rarely see such an error in a new caliper. It turned out that the customer was using measuring rods that had been kept in a warm storage area and the calipers were in an air-conditioned room. Sure enough, after she let them acclimatize to the same temperature, the error was gone! Lesson to remember: be sure that your measuring rods and your calipers or micrometers are both at room temperature. If you don't think this matters, just try an experiment. You can easily be off by .001" over 4 inches.

Q: When measuring hysteresis on my dial indicator, do I have to reset the dial to zero before I measure the down stroke?

A: If you calibrate your dial indicator you'll notice a slight difference between readings going up and readings coming back down. This is hysteresis. But, do not reset the gage to zero when you've reached its upper limit. Simply back down again and take the readings as you go along. Manufacturers publish the hysteresis errors you should expect for their gages. It's quite likely that in normal use this will have little or no effect on your measurements.

Q: Why do there appear to be no standards for hysteresis on indicators with more than one inch of travel?

A: Hysteresis is normally measured using a micrometer spindle. You have to be able to move the indicator's spindle both in and out and only a micrometer spindle can do that. As you know, micrometer spindles have a measuring range of only 1 inch. That's why you can't easily measure hysteresis beyond the indicator's one inch travel.

Q: My questions it to Starrett, and now to you. Where can I locate the specs and stated accuracies of the individual dimensional tools that I see come through our Calibration Lab? For example, we see many Starrett 25-441 Dial Indicators, 436.1XRL-1 Outside Micrometers, 124 Inside Micrometers and 445AZ-6RL Depth Gages but I cannot locate any published specs or accuracies for any of them.

A: Don't you find it peculiar that Starrett doesn't seem to publish specs for their gages? Their indicators are made to conform to American Gage Design specs but they leave the details to your imagination. I would apply generic accuracies of ± one graduation for the first 2-1/2 revolutions. After that, anything goes. As for micrometers, all you can do is report the accuracies that you find in your tests and let the customer decide if this is accurate enough for their purposes.

Cleaning

Q: We use a lot of AGD indicators and they often come in contact with water soluble oil that we use as a coolant in our milling machines and lathes. This coolant when it dries leaves a sticky residue on the indicator stems on both ends. I have tried alcohol and starting fluid to clean this sticky stuff off of the indicators but it only seems to help for a little while. Do you have any recommendations of a good solvent that would easily remove the residue and help keep the stems moving freely?

A: We encounter the same problem. Often these gages are sent to us for cleaning and the insides have become completely gunked (to coin a phrase). Usually, using an ordinary household cleaner like Fantastic or the new "Green" products works. You may want to give that a try. Be sure it doesn't get inside the gage, though. The water content will result in rust on susceptible parts.

Q: Is there anything you can do to the indicators to keep the coolant out?

A: I know that people have tried putting them in plastic bags (which sounds dangerous to me) and some have resorted to plastic shields that can divert some of the spray. This all makes reading the gage difficult and is only a stop-gap measure. I think you should closely examine your set-up to see how it can be modified in order to keep the coolant away. I say that because most users do not report any specific problems which implies that they've found an acceptable solution.

Q: I have a Microrapid micrometer which has had someone's initials engraved into the printed frame. is there any way to remove these and repaint the frame?

A: I'm guessing that you would have to grind away the initials, sand it flat and/or fill it in with metal filler and then repaint. "Hammer Tone" is pretty much what the paint is called. The best way is to disassemble everything and then proceed with caution.

Q: I have a Tesa pin style micrometer where the lines and numbers on the revolving barrel are worn off and difficult to read. Is there any way to fix this?

A: If the lines are engraved then we use black wax and rub it over the area. The wax stays in the grooves after it is wiped off the surface. Nowadays we're more likely to use a black magic marker but this can leave a slight stain on the metal after wiping off with solvent. You may have to experiment a little to get it right. If the lines are not engraved, there's nothing that can be done other than replacing the parts.

Mitutoyo USB and SPC Output

Q: What is the blue button on the Input Tool used for?

A: It's another way to send the data from your tool to the computer. You have the option of using the data send button on your tool (such as a caliper), or the data send button found on some cables (see listing above) or the blue data send button located on the front of the input tool. When you push any of these buttons, the data is transferred to your computer and it is entered in the spreadsheet cell.

Q: I am looking for confirmation that model 500-464 is equipped to load data directly into Excel database. Does it come with connecting cable and Input Tool or do those need to be ordered separately?

A: The calipers are ready for SPC hookup but you will need to buy the cable and the input tool separately. You will not require any software other than what you already have. See page 175 of our website for details.

Q: If you are not in a spreadsheet when the data send button is pressed, what will happen?

A: We know that you can also send data to Word or Notes, but we don't know what will happen if you have your address book open, for instance.

Q: It seems that Mitutoyo and Tesa offer similar systems for data collection but Tesa doesn't need an Input Tool. Isn't that more economical?

A: The one significant difference appears to be that the Mitutoyo set-up will allow you to import to a spreadsheet without any other program requirements even though you need the Input Tool. The Tesa systems comes with a CD demo version of DataDirect which you must install and, unless you buy the complete version (directly through the CD), you will only have limited access to data collection. (The limit is one hour per session, after which you will have to reboot.) It seems to me that the Mitutoyo system offers greater flexibility since you won't be bothered by the vagaries of (another) computer program and its associated bugs and glitches.

Q: The transmitter hanging from the caliper seems cumbersome. What are the dimensions and weight of the transmitter?

A: The transmitter is cumbersome. It is about 2" x 1" x 1" and weighs 23 grams.

Q: Are there any special handling procedures to assure the transmitter does not break away from the caliper during measurements?

A: Two screws are used to attach the transmitter which pretty much keeps it in place.

Q: We have been using  Mitutoyo SPC data for a couple of years now. We LOVE it! However, we have run into an issue lately where the data is not being input into Excel. If I hook up the calipers into another computer it works fine..... any suggestions on the laptop we have been using for the last couple years? I'm ready to pull my hair out!

A: Since the calipers and the input tool work fine on another computer, we'll have to suspect that something went wrong on the laptop. We wonder if you have had a recent update of Excel that might have changed some settings? Remember that updates can happen without your even being aware of them. That's one suggestion but probably not the one that will solve the problem. I suggest you contact the Mitutoyo Tech Department on this issue and I'm confident that they can work it out. Call 1-630-978-5385
 

Groove micrometer

Q: I need something like the Starrett 260M Groove Micrometer to measure o-ring groove width and axial position. Would you recommend this product? If not, can you recommend one?

A: I think you'll be okay with this Starrett micrometer. There's no significant difference between this one and other brands. We might as well support our own economy!

 

Pin Gauges

We were asked: "Not sure about the + or minus on the accuracy. Not quite sure how this would apply to my application. Any advice?" If the hole to be measured is exactly .500" then a pin which is .500" +.0002" wouldn't fit, but a pin which is .500" -.0002" would slide in. I assume this is the kind of application you have in mind. You are measuring a bore (in a shell) by seeing which is the largest pin that fits. In that case, you will want the pins with a negative tolerance.

 

Starrett Last Word indicator

Starrett Last Word indicators have problems which are as unique as their design.

If you encounter a hand that sticks on rare occasions and refuses to budge, try tapping the indicator with a screw driver or bang it lightly on the surface of a table. The hand will probably dislodge and go back to normal. This can happen when you have moved the contact point too quickly. If the hand always skips at a certain spot, you will need to have it cleaned or repaired. Refer to page 117 for a more complete details.

Q: I have a nice, functional .0001" Starrett 711-T1 (which is apparently obsolete now) and the bezel is a little loose; it rocks out of the plane of the dial. There are three, small flathead screws evenly distributed around the bezel. Will gently tightening these tighten up the bezel? If not, is there an alternative means of doing that?

A: The three screws you mention will have no effect on the rocking. The mounting plate has come loose and those screws can only be accessed by removing the bezel, the hand and the dial.


 

Measuring rods - micrometer and caliper standards

Q: I just received a measuring rod from your company, and I was wondering about the proper way to store it. It came with a greased plastic protective cap for each end, and I was wondering if I am supposed to throw these caps away, or keep them to store the standard when it is not in use. Also, I am assuming that I need to wipe the grease off before using them to standardize a caliper? Sorry for the basic questions, I’m new to calipers.

A: Keep the plastic tips and put them back on the rod when you store it. This way the critical surfaces are protected.

 

Wipe all of the grease off. It's only there to protect the steel during its trans-Pacific voyage. If you need to store the rod in a humid environment, or put it away for a long time, you should coat it with some oil. Just put a few drops on the rod and rub it with a cloth.

Q: What happens when the micrometer is calibrated at 70° but subsequently used at different temperatures? Will the readings be accurate?

A: For initial calibration, the standards and gages should be at lab temperature (about 20°C). Both items should be acclimatized for about 24 hours. When the micrometer is used at any other temperature, then you will have to consider the coefficients of expansion for the metals or materials being measured in relation to the expansion of the steel used on the micrometer. Frankly, no one worries about this, but it is worth an experiment or two if the measurements are particularly critical. In any case, allow the micrometers to reach the same temperatures as the parts.

Q: What is the frequency of calibration for measuring rods?

A: "One year" seems to be the catch-all and stock answer. It seems to us that, if the rods are used on a daily basis, then they should be certified much more frequently, perhaps every 3-4 months. On the other hand, if you use them only twice a year, why wouldn't they be good for 10 years? You will have to check with your own—or your customer's—quality program to see what their requirements are, logical or not.

Refer to page 58: Measuring Rods for further information.

 

Micrometer lapping

Micrometer lapping is tricky only because results aren't always good. The micrometers should be repaired and lapped at the same time to assure accuracy. If the spindle bushings are loose, for instance, your micrometer anvils will never remain parallel. Yes, we can perform "lap only" (which means the anvils will be flat and lie parallel when the micrometer is not in use) but the gage will not be guaranteed to read accurately. It's always best to request a complete repair.


 

Mitutoyo digimatic calipers

Q: My digimatic caliper jaws attract metal filings. Is it okay to run these through a demagnetizer?

A: The jaws of digital calipers can become magnetized, for one reason or another, and will attract metal filings and chips. Not only do these grind away the flat and parallel jaws, they will also create reading errors if they are not carefully wiped away before measuring. Tests have shown that it is perfectly alright to put the jaws through a demagnetizer without causing harm to the digital components, although it would be a good idea to remove the battery first.

Q: I have an electronic caliper, Mitutoyo Model CD-8”CS, Code 500-197. There is a problem with the battery connection. I can put in a new battery, but get no display when I press the “power on” switch. The battery contacts are definitely making contact with the battery. Maybe you have come across this problem previously (if this particular caliper design has a repeating failure mode). In your experience, what should I expect to pay as a typical repair cost?

A: Since you have an obsolete model, and parts are unlikely to be available, I would just replace it with a new one (see page 135). By all means, buy another Mitutoyo since they are the most reliable. (Keep in mind that parts for digital gages will always become obsolete as new innovations come along. That's just one of the prices we have to pay now-a-days.)


 

B&S Dial Caliper

Q: I am emailing to ask if you have had any experience with the Brown & Sharpe Valueline 6” calipers, built in China? I am apprehensive to add them into our system. If you can share your opinion of these, I would greatly appreciate it.

A: We have no experience with these calipers. I would suspect that they work just as well as any other. The drawback would be the lack of parts if a repair is required and this can include little things like replacement crystals or bezel lock screws. You may want to order one just to see how you like the feel of them, how smoothly they travel, and to check the hardness of the steel jaws. If the jaws are on the soft side, like the Starrett calipers, they will bend out of parallel and wear down too quickly. At Long Island Indicator we avoid dealing with any Chinese-made gages. The workmanship is usually inferior.

Q: I have noticed some of the 579-5 calipers don’t have the nice smooth action that I find with the 579-4 calipers. Are they different in some way? They appear to have the same parts, mechanically, so I’m guessing it’s in the assembly between the rack and pinion gears.

A: Caliper 579-5 and 579-4 are identical except for the color of the dial. You should not notice any difference in function although we find that the older models ran smoother. This may have been due to tighter tolerances in manufacturing of the beam.

Q: Is it possible to order an inch rack with the scale already on it?

A: The scale is printed on a strip of metal which has to be glued to the top of the rack. The scale has a self-stick lower surface. The scale and rack are sold separately and not assembled.

Q: I read that you guys recommend the white face on the Brown and Sharpe calipers unless people have experience with the black face. Why is this?

A: The red hand on the black dial may be hard to see for people with diminished vision or people who are color blind. Also, red is a hard color to see in dimmer lighting. Some red hands will wash out over time and become pale orange or even white. Not a good thing. Sticking to the black hand / white dial avoids potential problems.

Q: We have some B&S dial calipers where the cover is loose and there is now roughness in the travel.

A: The covers are snapped in place over 4 plastic sockets. These sockets can become misshapen, especially if the cover has ever been removed. That will cause the wiggling you notice. It has no effect on the caliper's smoothness. That's most likely caused by a poorly adjusted gib, damage to the gear teeth, or misaligned gears.

Q: I have a pair of Brown & Sharpe dial calipers that I recently had to repair and reassemble. Upon getting everything back together and timed correctly they do not seem to repeat. I assume it has something to do with the coil spring on the front gear needing the be pre-wound to preload the dial.

A: You are correct. The plastic gear (on the right) needs to have a preloaded spring. It's a bit tricky, and too hard to describe in words, but you'll figure it out. We did.

 

Peacock

Q: The biggest problem I have with Peacock test indicators is that the flanges for clamping are somewhat narrower than the normal size so I have great difficulty stabilizing them to check their accuracy, which usually isn’t too bad if I can keep them in 1 place long enough to check a few points.  Is there another standard size, other than that I’ve seen on Interapid, Mitutoyo, Starrett, Fowler, etc? 

A: I am not surprised that the dovetails on the Peacock indicator aren't of the same standards as the European (and Mitutoyo) models. The Chinese are usually responsible for this kind of error and this makes me wonder where, exactly, the Peacock is made these days? Of course, the dovetails should all be of a uniform size. Refer to page 201 for information on the "ideal" dovetail.

 

Moore & Wright

Q: I am wondering why you do not have any info at all about the Moore & Wright products? They used to produce very good quality measurement tools. Perhaps now a lot of their tools, like Starrett, are made in China too, I am not sure.

A: Our reviews and information are based on personal experience with the tools. We have included everything we have ever laid hands on, here in the US, in the past 50 years. Moore & Wright is now part of the Bowers group of manufacturers operating mainly in the UK and other British outposts. They have a comprehensive catalog of items manufactured in England and China. A simple google search will bring you to their web site.


 

Chamfer Gage

Q: We recently purchased a 0.500" Set Master Ring for setting chamfer gages from you. Can you forward the procedure for recovering the "Set To" value if this value is not known, using this setting ring?

A: Insert the 3-winged anvil into the .5" setting master and if the indicator does not read .5" (with the dial at the 12 o'clock position) then you will have to make an adjustment. Loosen the upper knurled ring which will allow you to move the dial indicator up or down as needed. Position the indicator so that it reads .5" and tighten the knurled ring again. You may have to adjust little by little since tightening the ring has the effect of changing the readings by a few graduations.

 

Now place the gage on a flat surface and take the reading. This will be the new "set to" value which you may want to inscribe on the back of the chamfer gage for the next user.

 

Remember that you can only use a setting ring which has no chamfer.

Refer to page 57 for additional information on the chamfer gage. 

 

Thickness gages

Q: I am inquiring whether or not the Mitutoyo 7322S Thickness Gauge with the 4.74" throat can be fitted with nylon ball tips. The item will be used to measure plastic ophthalmic lens thickness.

A: Only the upper (movable) anvil can be replaced. The lower anvil is permanent. You could take a nylon ball, cut it in half, and cement it onto the surface of the lower anvil. This will work because the indicator is adjustable for zero setting.
 

Q: I am measuring the thickness of rare stamps where a few .0001" difference in paper thickness can translate into thousands of dollars in value. I'm concerned about the anvil force since I know nothing about Newtons.

A: The force (N) will be quite acceptable and will always be constant between readings. Just don't move the stamp once you have it between the anvils. Lay the stamp down, allow the anvil to close (come down), take the reading, lift lever to raise the anvil, and only then remove the stamp. Never attempt to pull the stamp out from between closed anvils. If a stamp were particularly brittle and might be damaged by any object placed on top of it, then I wouldn't subject it to the stress of a thickness gage either.

Etalon micrometer

Q: I have 5 very lightly used Etalon mics (older style with metal locking levers). They must have sat around for a long time because the friction thimbles are all gummed up and the barrels are stuck so I cannot zero them.

A: Use "Liquid Wrench". Let it soak for at least a day, turning the thimble a little bit to either side, from time to time. The thimble will probably work itself loose. Then you will want to loosen the friction screw on the thimble. Put the thimble back on and work the spindle again until it feels right. "Liquid Wrench" is better than WD-40 for this situation.

Q: The end of the Etalon indicating micrometer spindle that assembles into the thimble is ~0.001" larger on the new spindle than our existing one. We are thinking we need to turn this down to the old diameter in order to get it to assemble, but wanted to see if you had any other recommendations or a "best-practice" approach to doing this?

A: As you have noticed, anvils and spindles are very much diameter specific. The manufacturer provides them in various diameters and they do not need to be lapped or turned down. You just need one that fits. I strongly urge you to send the micrometer to a qualified repair shop for service. This is one aspect of micrometer repair that does not fall under the do-it-yourself category.

 

Starrett dial caliper

Q: I just received my replacement anti-backlash gear for our Starrett 120A calipers, but when I went to replace it I realized that it’s not as easy to get at the gear as I had assumed.  Is there an instruction sheet available somewhere that I could use?

A: Starrett dial calipers have unique, cleverly simple movements and backlash gears. Be careful when taking these apart because parts tend to come loose and fall all over the place. Keep your eye out and remember what goes where. Although deceptively simple, if you think you are "all thumbs" this repair attempt may prove it. For some hints on do-it-yourself repairs, take a peek at page 44.

Q: Could someone let me know how to remove the bezel/dial, as it seems there are screw heads beneath that that I can’t get to otherwise?

A: On newer Starrett models, the bezel is held in place by a rubber o-ring. You pry the bezel off, gently, by slipping a large, flat-bladed screwdriver under the rim of the bezel. Crystals are inserted with a crystal press and the bezel can be pushed back on when the repair is done. If you need parts, see page 111.

 

Starrett dial indicator

Q: I am considering lengthening the spindle of my plunger-type (i.e. in and out) dial indicator and wonder if that would effect the readings? It seems to me that your considerations on tip length and cosine error on your web site (page 15) refer only to the “lever”-type of indicators. Would I get the same readings if I lengthened the plunger-type spindle from its original length of about 2 inches to 4 inches?

A: Length has no effect on dial indicators. You will be perfectly fine increasing to 4 inches.

Q: I need a new bezel with crystal for my 25-631 starrett dial indicator,  I see you have two listed.  One is plastic and the other is metal, will either work on my indicator? 

A: All the old metal bezels have been replaced by the new plastic which are easier to install and remove. Order the plastic at this time.

 

On your indicator, you will notice a wire retaining spring that runs around the indicator body. The metal bezel would slip over that wire. You can now remove it because the wire is no longer needed. The plastic bezel pops into the same groove that held the wire. For parts see page 224.

Dial Caliper Gage (Intertest)

Q: I want to ask if you have a instructions for the correct use for the inside dial caliper gage, that we use to measure grooves? We have a real problem because some mechanics say they get different measurements with the same instrument and we want to know what is the correct way to measure.

A: The gage is difficult to use, there is no question. You must "rock" the gage back and forth in all directions to find the highest reading on the dial. This is not an instant process. If the gage leans to one side or the other, you will get different readings. You may have to take several readings (three or more) each time, to find the average. It is best to experiment first and allow the mechanics to discover on their own the correct way to use it.


 

Micrometers

Q: I have an old B&S micrometer.  It doesn't appear heavily used, but there is a tiny bit of looseness where the main shaft passes thru the sleeve near the spindle lock. It has maybe about .001 or so side-to side wriggle. I'm not sure if it was because there used to be rust on the shaft, and this rust reamed out the sleeve. Anyway, I wanted to ask if this was normal, and if you happened to sell a replacement sleeve that I could press in myself.

A: There should not be any play whatsoever in that bushing, as you probably suspect. There are no replacement bushings available so the micrometer is pretty much unrepairable. If you remove the spindle, you can try to close-in the opening but, if successful, it would only be temporary.

Q: My Uncle gave me an old micrometer. It still spins, but it has rust on it. Can you recommend an appropriate action for me to take?

A: Take it apart, coat with Liquid Wrench and let it sit for a day or two, then take steel wool to it until the rust is gone. That should take care of it.


 

Dial Calipers

Q: I recently bought an older pair of Tesa dial calipers. On the OD jaws, there is a very small gap at the thiner part of the jaws--the end portion. The flat portion of the OD jaws is parallel and has no gap. Is this normal for these calipers?

A: This is common in calipers after they have been used a while or if they have been misused. In other words, if the front of the jaws are always used for measurement (they will wear down) or it the jaws are used to open paint cans, for instance. We suggest you measure only with the inner part of the jaws and if you have to use the blade, you may want to make allowances. Use a gage block to see how much of an error to expect

 

Test Indicators

Q: We use a test indicator to qualify radial runout of the work rolls on a cold rolling mill. This check is made with the machine in ‘jog’ – so that the work rolls are preloaded. Unfortunately, the test indicator is exposed to the oil used for coolant. The one we are using now has oil inside the dial, and we are looking to replace it.

• As you noticed, test indicators are not coolant proof, and many indicators come here for repair because the hair springs have become oily and stop functioning. Your indicators can be sent for cleaning as well. The cleaning bill will be less for single revolution indicators so you might want to buy only those models in the future. Bestest or single revolution Compac indicators may be a good choice. You could also opt for a disposable indicator made in (gasp!) China. You can probably buy them for less than the cost of repair and just throw them away when they stop functioning. Repairs (even cleaning) will not be possible on those.
   

Q: Do you have or know of any needles for an Interapid test Indicator that are not attracted to a magnet?  I know there are ones where the tip is ruby or carbide, but I am looking for something where the whole needle is immune to magnetism.

• Titanium is considered paramagnetic which means it holds negligible amounts of magnetic charges for very brief intervals. We don’t have any of these for the Interapid indicator but they would work on Mitutoyo models 513-212, 513-412 and 513-446. (for details, refer to page 21)