Questions & Answers

Questions posed by customers and readers, answered to the best of our ability.
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Mitutoyo dial calipers

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.

 

Interapid test indicators

Q: I have a model 310-B1. I see that parts are no longer available. The only thing wrong with the indicator is that the face comes off easily. The plastic split-ring that holds it on needs to be replaced and I was hoping that there might be another indicator that incorporates the same ring that I could purchase. Please let me know if that is the case.

A: Those are exactly the parts that are the weak link on this indicator and those rings are long gone... no one else uses anything like it. The other missing item is the little horse-shoe shaped clip. If you really love this indicator, I suggest you try to improvise a way to hold the bezel in place. A properly shaped piece of spring wire might do the trick.

Q: I have an Interapid model 312-b3 indicator. I need to use it to center a rifle barrel (center the interior bored hole) in a lathe at a point fairly deep into the hole. I believe I could use your long indicator points for this operation as long as IÕm aware that the accuracy of the dial is decreased.

A: If the contact point is exactly twice the length of the standard point, then the graduations on the .0005" indicator will equal .001" and the graduations on the .0001" indicator will equal .0002".

Q: I recently purchased an Interapid 312B-1V (used, no directions). In order to move the contact you state: "be sure that the point is securely fastened before attempting to move it." Would this mean to ensure point is tight in holder then run the contact against the stop? Then move to desired angle?

A: As you've probably noticed, the contact will swivel (with a bit of force applied) in two directions. Just make sure that you've completely screwed in the contact point before you swivel otherwise you might break off the point in the process.

Q: I have an older Interapid test indicator, model # 311B-1 and I was wondering if by any chance you would still have parts for it? The part I'm looking for is the one that holds the bezel to the extension ring. It looks like a horse shoe, or if you know of any company that makes replicas such as this.

A: We called it the horseshoe clip at the time. No one makes this part as far as I know. People have been known to improvise with a bit of copper wire which can pretty easily be bent into shape and filed down if necessary.

Q: I have a brand new Horizontal model 312B-15 with 2.75" long contact point. I ordered the wrong one, so I bought some shorter tips for this indicator, now it acts jerking and does not repeat with a shorter tip on it. Does this mean that I can only use the long tip?

A: The long point models have a different hair spring to compensate for the weight of the point. Apparently replacing this with a short point causes the jerkiness you've noticed. The only thing you can do is stick with the long point, or have the hair spring replaced.

Q: The paint is peeling from my Interapid indicator. Can I do anything?

A: This problem is seen more commonly among the older models. Certain solvents softened the paint and it eventually began to peel. We don't see the problem anymore on newer models. My suggestion is to scrape off the peeling paint. You'll end up with a shiny brass body which isn't so bad looking after all. Trying to repaint is usually an invitation to failure. For one thing, you'd have to disassemble the indicator completely and unless you really know what you're doing... please don't!

Q: How could I sterilize an Interapid indicator used in biological experiments?

A: Surface cleaning with isopropyl alcohol can be used, just don't immerse. There is a small amount of oil in the bearings and we have to be sure that these don't dry out. Dried oil becomes gummy and that would be detrimental. For complete sterilization, Gamma radiation may work very well. I don't see how it could damage any of the gage's components as long as no excessive heat is produced. Having never tried this, though, it is only a guess. Ethylene oxide can be used if it doesn't dry the oil. I don't know if it would. If the crystal becomes fogged by the gas, you'd have to replace it, but that would be part of the cost of sterilization. Autoclaving to 120-degrees is probably too severe a method. The presence of steam would be quite damaging. I would avoid this method unless dry heat can be used. In summary, use the alcohol whenever possible, before resorting to any of the other methods.

Q: The contact point moves up and down (forward and backward is a better description) but one direction is noticeably harder than the other. Shouldn't they be the same?

A: Ideally yes and probably in a new indicator this will be the case. Interapid indicators have a spring mechanism that controls this force which is quite different from any other manufacturer's. Unfortunately it can not be modified without taking the entire indicator appart. Don't attempt this unless you already know how to put it back together! The spring can weaken in one direction over time but the problem is more likely the result of previous repairs. Just the act of taking the mechanism apart can distort the spring's shape. The difference in force shouldn't matter much but if it's imperative to your operation that they are identical, you should consider switching to a different brand. Bestest, Tesatast and Compac would be ideal substitutes.

Q: We have an Interapid 312b-2, the hair spring is currently not wound up, when you're looking at the dial and needle as if you were using the indicator, would you spin the needle clockwise to put tension on the spring or counter clockwise to put tension on the spring? The crown gear has a bent tooth which stops the large needle from turning more then 4 revolutions in the counter clockwise direction. Can the crown gear be removed and turned so the bent tooth doesn't hinder the movement?

A: You will have to disassemble the gage in order to pre-load the hairspring. When it is apart, you will see the direction required. The crown gear can also be positioned so that the damaged tooth is not engaged.

Q: I know you have been asked before, but I really don't like the peeling paint on my Interapid. Isn't there something I can do?

A: Of course there is. You will have to completely disassemble the indicator until you have just the body left. Use paint stripper if it still has bits of paint on it. Then spray with a primer followed by a color of your choice. Be careful you don't get any paint onto any of the screw threads or you'll have a heck of a time trying to get the screws back in. Here's a handy hint: if you don't mind spending the money, just buy yourself a new body instead. Then your indicator will look like an original and the paint on the new bodies will last much longer.

Bestest indicator

Q: I have a Brown & Sharpe BesTest 7031-5, and needs to have the crystal face replaced (cracked and cloudy). If I buy the replacement part, how do I change it? Or, do I need to send it out for repair?

A: You can replace the crystal if two conditions exist: 1. You are able to remove the old crystal. 2. The bezel is still in perfectly round, undamaged condition. In that case, the new crystal can usually be pressed in place with the thumbs. It may be safer, however, to send the indicator along with $27 and instructions to "replace crystal only". We would take care of this immediately.

Dial indicators

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

A: It's 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.

 

Compac indicators

Q: I am interested in the Compac 213GLA test indicator. Your website said that some have had dials that were not printed very well, though, but also that Compac was your indicator of choice for 4 decades. Are the dials back up to snuff?

A: The dial problem is sporadic and most often the dials are perfectly fine. You may need a magnifying glass to notice any defects. We tend to be overly critical in this respect, probably to our own detriment.

Q: What is the best way to preserve the dovetails in the long run on something like the Compac, with integral, non-hardened dovetails?

A: The body, and dovetails, is brass with a hard chrome finish. If you do not over tighten the dovetail attachments you will not cause any damage. Should the indicator be ripped from its holder, then the dovetail will probably have an unrepairable gouge. Fortunately, the indicator has 3 dovetails and you can always switch to using one of the others.

Q: I want a quality dial test indicator where the dial hand always moves clockwise whether the point is pressed from either direction and no "reversing lever" to worry about. I also prefer .0005" graduations, 1.5" dial, and .060" movement or close to it. I was under the impression the Compac worked in this manner, but I was just told they work just like my interapid.

A: Compac hands always go in just one direction (clock-wise) no matter how you deflect the contact point. Compac can be hard to come by at the moment (because of temporarily suspended production) and we don't have model 214GA which would be the correct one for you. In this case, consider the German-made MarTest as shown on page 235. With these, the hand also moves clock-wise at all times. There is no reversing lever to deal with.

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.

Correx tension gages

Q: Is it okay if we apply more tension than the gage's range? For instance, can we apply 4 cN on a 3 cN gage?

A: Yes, you can apply more, within reason. The gage simply will not register anything above the upper limit, when you exceed its range, but no harm will be done.

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. If you don't have the tools, you might want to contact Richard Nadeau at 1-480-786-9400 (in Arizona) to see if it's a challenge he'd like to take on.

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 micrometers

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!

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.

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

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.

 

Measuring rods - micrometer and caliper standards

Q: What happens when the micrometer is calibrated at 70° but subequently 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.


 

Micrometer lapping

It is tricky lapping 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: 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.)


 

Blake Co-Ax indicators

Q: I have to indicate a 10-inch diameter. Which length point should I order?

A: The 5-inch point will indicate a 10-inch diameter, but you can always get one longer. The 6" will work fine because a longer point can be used to indicate a smaller diameter. It doesn't work the other way around, though.

 

B&S dial calipers

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.