Interapid Test Indicator Contact Points
Genuine MTC contact points with carbide, ruby, Nylon or Teflon balls

We also have contact points for the following indicators:

  • Bestest and Tesatast M1.4 indicator contact points … page 218
  • Compac M1.6 carbide and ruby test indicator contact points … page 205
  • Interapid M1.7 carbide, ruby and Teflon contact points … this page (see below)
  • Mitutoyo M1.7 test indicator contact points … page 186
  • Starrett test indicator contact points … page 239
  • contact points for dial indicators are shown on page 133

Interapid M1.7

 

How are they measured? From the shoulder (not including the thread) to the center of the ball. Contact point thread size is M1.7 x 0.35 Those are the measurements given below.

Why do many catalogs have different lengths from those listed below? The Interapid carbide point lengths shown in the catalogs are the length of protrusion from the front of the indicator. A useful figure in some circumstances but not particularly helpful if you have a handful of contact points and you need to sort them out. We have also listed the actual length of the point from the shoulder to the center of the ball as a reference.

Interapidcontactpointlengthdrawing1 

Usable, exposed catalog length is the amount of protrusion (L) as shown in the sketch. The actual length is about 2 mm longer.

Ball diameter is .080" (2 mm) on new Interapid indicators. Carbide is standard with these models.

 

For accurate readings, Interapid contact points must be at an angle of about 12-15 degrees from the work surface. This is more critical with .0001" indicators where errors can quickly add up.

 

Model

Length

Ball Diameter

Price

Our Ordering Number

Manufacturer Equivalents

312B-1
312B-2
312B-3
312B-4
312B-20
312B-1v
312B-2v
312B-3v
312B-20v

74.111370
74.111371
74.111372
74.111373
74.111374
74.111377
74.111378
74.111957
74.111379

.687" actual
.650" exposed

.015" carbide

$21.50

MTC39-02 buy now

74.116284

.031" carbide

$19.50

MTC39-03 buy now

74.105998

.060" carbide

$19.50

MTC39-04 buy now

74.105997

.080" carbide

$19.50

MTC39-05 buy now

74.105996

.060" Nylon

$29.50

MTC39-19 buy now

none

.060" Teflon

$29.50

MTC39-16 buy now

none

.080" Teflon

$29.50

MTC39-17 buy now

none

.040" ruby

$29.50

MTC39-13 buy now

none

.080" ruby

$29.50

MTC39-14 buy now

none

Model

Length

Ball Diameter

Price

Our Ordering Number

Manufacturer Equivalents

312B-15
312B-15v

74.111958
74.111965

2.750" actual
2.675" exposed

.015" carbide

$21.50

MTC40-33 buy now

none

.031" carbide

$21.50

MTC40-34 buy now

74.111910

.080" carbide

$21.50

MTC40-35 buy now

74.111913

.100" carbide

$21.50

MTC40-36 buy now

74.111912

Model

Length

Ball Diameter

Price

Our Ordering Number

Manufacturer Equivalents

312-1
312-2
312-1v
312-2v

18.5 mm actual
16.5 mm exposed

2.0 mm carbide

$19.50

MTC40-05 buy now

74.105993

1.5 mm carbide

$19.50

MTC40-04 buy now

74.105994

0.8 mm carbide

$21.50

MTC40-03 buy now

74.105995

Model

Length

Ball Diameter

Price

Our Ordering Number

Manufacturer Equivalents

312-3
312-4

17.2 mm actual
15.2 mm exposed

2.0 mm carbide

$19.50

MTC40-15 buy now

74.110482

1.5 mm carbide

$19.50

MTC40-14 buy now

74.110491

0.8 mm carbide

$21.50

MTC40-13 buy now

74.110507

2.0 mm Teflon

$29.50

MTC40-17 buy now

none

Model

Length

Ball Diameter

Price

Our Ordering Number

Manufacturer Equivalents

312B-1
312B-2
312B-3
312B-4
312B-20
312B-1v
312B-2v
312B-3v
312B-20v

double length**

1.450" actual 1.375" exposed

.030" carbide

$21.50

MTC39-33 buy now

74.106363

.060" carbide

$21.50

MTC39-34 buy now

none

.080" carbide

$21.50

MTC39-35 buy now

74.106361

.120" carbide

$21.50

MTC39-37 buy now

none

* the use of these very long double length points on the .0005" indicator is not condoned by the manufacturer. The indicator graduations will now be equal to .001". If you are not using your indicator to make actual measurements, then it does not matter what length point you install. Buy and use these at your own risk. For details refer to page 23.

** you can use these double length points on any of the models listed. The readings on the dial will be doubled as a result. The graduations on the .0005" indicator will therefore equal .001" and the graduations on the .0001" indicator will equal .0002". This only works if the contact point is exactly twice the length of the standard point.


 

Interapidcontactpointwrench1

Contact point wrench 18.60307 order now


The Indexable bent contact point is designed for use with Interapid test indicators and the photograph gives you an idea of its use.

Any notion of taking direct readings goes right out the window, however. This contortion means that you can only use your indicator for the purpose it was designed: comparison work. If you're not sure whether it'll work for you or not, buy just one piece to test it. We make no guarantees.

Ball diameters are limited and they're only available in carbide. Dimension A and B are approximate.

Length A

Length B

Carbide diameter

Order No.

Price USD

.6875"

.3"

.031"

MTC41-01

30.00

.6875"

.3"

.060"

MTC41-02

30.00

1.45"

.3"

.031"

MTC41-03

32.00

1.45"

.3"

.060"

MTC41-04

32.00

Questions?

 

Additional information on test indicator contact points:

 

Q: I have an Interapid for calibration, but it seems to be off incrementally. It’s off as much as .003” over a full rotation. Is this a spring issue or does it need something else?

  • That’s a big error and is most likely because you have the wrong length contact point installed. Also remember that the contact point must be at an angle of about 12-degrees to the work surface, not horizontal like most other indicators.

     

 

LONG ISLAND INDICATOR REPAIR MANUALS

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
 

www.longislandindicator.com

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


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This page's most recent revision: 26 APRIL 2018
All Rights Reserved

Original photographs and content copyright 2018 by JWGrum

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