Interapid Test Indicator Repair Service


The Interapid indicator can be counted on as being one of the most challenging to repair. Ask anyone who's tried to give it a go without proper tools and without doing considerable research first.


Here you see the gage taken apart and soaking in cleaning solution, ready to be repaired. It's going to work as good as new when we're done. Guaranteed.

And here is what we will do if you choose to send your damaged indicator to us:

• total disassembly
• cleaning of all parts with appropriate cleaners
• inspection of all parts under high magnification
• repair or replacement of all worn or damaged parts (those parts which are necessary for the full functioning of the gage)
• lubrication with appropriate lubricants
• reassembly
• inspection for functionality
• calibration using equipment and standards certified traceable to NIST
• your satisfaction is guaranteed upon return of gage or we'll issue credit, refund or rework as per your instructions


Other options

Here are several examples of repairable issues you might run into:


The small hand can be tricky to remove without tools and, if not careful, it is just as likely to launch itself into space, never to be seen again. Fortunately parts are available but they are expensive and you are much better off being careful along the way. For a parts breakdown, refer to page 88.


The hairspring can be an intimidating challenge. It has to float horizontally without touching the gears and, of course, it has to be immaculately clean so that it coils properly. Only fine pointed tweezers can deal effectively with the hair spring. You should also go easy on the caffeine.


Unless you can give the spring the correct amount of preload, the indicator hand will not repeat and the up-and-down contact point motion is probably only going to work one way. One-way is great for city streets but not for your Interapid.

Option 1.

Should you decide to "do it yourself" we can offer you our own Repair Manual (at a price, of course). Check with page 208 to see what's included and to order your copy.

Option 2.

For a fixed price we'll do all the dirty and tricky work. We've been repairing Interapid indicators for nearly 60 years and can legitimately claim to know a thing or two. Turn around time varies with the seasons and page 30 will provide you with all the details.

Option 3.

You may decide that it's high time to replace the gage. There have been improvements in recent years and the Interapid remains one of the best choices. Page 23 will show you what's available and will also lead you to some of the best on-line pricing.

Questions and Answers about the Interapid indicator

Q: I have a Brown & Sharpe Bestest model 7025-4. I need the tiny screw on the face, and a new crystal for it (1.5 inch approximately). I didn’t see that model listed anywhere on your site. Will you help me out with these?

  • The 7025-4 is actually an Interapid 312B-1 indicator. For a very brief time, Brown & Sharpe had its name put on the dial. This only confused everyone, and it still does.

Q: We have a machinist with a Brown and Sharpe Dial indicator 7026-4. He is looking to replace the stem he uses in a collet/chuck in a CNC. Do you have this available?

  • Model 7026-4 is the same as Interapid 312B-2. It was sold under the Brown & Sharpe name for a brief period of time in the 1970s. For parts, see page 88.

Q: Is there a way to check and adjust the Interapid “stem” to contact point concentricity? The machinist in our mill department often uses the Interapid to centralize the spindle to the centerline of a hole in the part by sweeping the hole.

  • There is no way this can be adjusted.

Q: What difference is there between the 312B-2V which lists as a .0005" model and the 312B-20V which lists as a .001" model? Is there any difference other than the additional lines (between the .001 lines) printed on the dial of the 74.111378 model?

  • There is no difference except the one that you suspect. The indicators are identical in every other way.

Q: I was reading on your website that there are counterfeit Interapid test indicators. Do you know how to tell the difference or do you have any information on identification of the fakes.

  • Although they look very much alike, the Chinese indicators DO NOT have the name Interapid on them. They are sold with names such as X-Test. All genuine Interapid indicators have the Interapid name printed on the dial

Q: I have two Interapid indicators. Both of these indicators seem to not read as close as my Brown & Sharpe Bestest indicators. Both Interapid indicators are 99.85% good and clean but I would like them to be a little smoother and trustful in the reading of them.

  • There are two differences between the Bestest and the Interapid indicators. You must keep these two points in mind when comparing them. They will never be equal in responsiveness nor in accuracy.
    1. The Interapid indicator is only accurate when the contact point is at 12-degrees to the work surface.
    2. The Interapid indicator has more moving parts meaning that it will be slower to respond and will have poorer repeatability, although these differences are almost negligible.

Q: My Interapid works fine but it has gotten very dirty. Don't tell me to wipe it with a paper towel because that won't work. Any suggestions?

  • Dip a toothbrush in some Naphtha and scrub away. Avoid getting solution inside the indicator. If Naphtha doesn't remove stains, use Simple Green or Fantastik on a paper towel (!), just be doubly sure you don't get any of these cleaners inside.

Q: You mention that the large hand of an indicator should be at 9 or 10 o’clock. What if it rests between 12 and 1? Is that a malfunction?

  • On the Interapid, the hand is at high noon when at rest. If it is slightly off, but is still accurate, then there is nothing to fret about. But, if the hand drifts or returns to various positions, then it should be checked out.

Q: Have you have seen any increase in warranty claims and/or quality issues with Interapid indicators 312B-1, -3, & -20?

  • Just the opposite, over the past 12 months we have seen a decrease since the manufacturer fixed a "bug" which had recently surfaced.

Q: If I purchase a new Interapid through an eBay seller, is the warranty honored by the manufacturer?

  • If the item is new when purchased, then TESA will honor the warranty. You would have to keep the purchase receipt to prove the date of purchase. It does not matter if the seller is an authorized distributor or not.

Q: Contrary to my nature, I thought I'd ask for advice before I screwed up something. After all, you do say "Unless you know what you're doing, you should under no circumstances attempt to disassemble or adjust any of the screws or bearings on the [Interapid] indicator."  However, on your "Do It Yourself" web page you say this about Interapid stem attachment: "You will notice that you can increase the swivel friction by tightening screw A." Can the swivel friction on the contact point be adjusted in the same way?  The contact point on mine doesn't want to swivel, and I'm worried that I shouldn't push any harder on it.  Also, should I put any oil on this friction clutch?

  • This is a good question and I'm glad you asked. The contact point friction can not be adjusted in any way. The Interapid has fairly hard friction on the point. After all, you don’t want it to move on its own. Don’t be afraid. The contact point angle can be adjusted. Just use your thumb and the point will yield. A tiny drop of oil can be put on the “clutch” if you still feel that there is too much resistance. 

Q: My Interapid seems a little jumpy, especially when changing direction. Is it in need of repair?

  • Jumpiness is most often the result of a dirty hairspring. When the spring gets oily, it stops functioning and needs to be cleaned. This is easier said than done and should be put in the hands of a professional.

More questions (with answers in our reference book - see page 178)

Q: We use the 312B series Interapid here on a daily basis. A few of them from time to time get abused by inexperienced or negligent machine operators. My question to you is, is there a way to zero out the small dial (rev counter) on these things? Repeatability does not seem to be a problem, I just would like to keep the needles in line as they were from factory.

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?

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?

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.

Q: We recently purchased a new Interapid 312B-3 indicator and noticed that the dial appears to slightly lift from the base. Is this common with these indicators ?

Q: I would like to know if the 2.75" #111913 indicator point can be used with the 312B-3 Interapid indicator? I believe that the divisions will now be 0.0005" instead of 0.0001" with this longer point.

Q: Can I get the small wrenches to change the Interapid contact point properly? The tips all have the small flat machined into the shank and a new indicator used to have one of these wrenches supplied with the kit but I haven't seen one with any of the new indicators we've purchased recently. It used to be a simple round disk with a notch that fit the flat on the tip shank. Without this a needle-nose pliers works but seems wrong putting a pliers on something so delicate.

Q: I purchased a spring and gear assembly for the Interapid indicator (312B-3) and I am having a difficult time getting the indicator to return to 0 accurately (within .0001). Part of the problem is adjusting the ball bearing with spanner nuts. Will you please help me with this?

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.

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 I'm aware that the accuracy of the dial is decreased.

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?

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.

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?

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

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

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?

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?

These and other questions about test indicators are answered in our exclusive new publications.




BesTest and TesaTast Indicator Repair Manual … page 177
Starrett 711 Last Word Indicator Repair Manual … page 199
Interapid Indicator Repair Manual … page 208
Compac Test Indicator Repair Manual … page 194
Mitutoyo Test Indicator Repair Manual … page 102

New! Companion Reference Guide for Test Indicators … page 178

Long Island Indicator Service Inc
14 Sarah Drive
Hauppauge NY 11788 — USA

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This page's most recent revision: 18 Ocotber 2019
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