Compac Dial Bore Gauges
inch reading

Compac model IA2A-IAP555A shown above, along with 2 of the contacts and extensions. You will have to purchase the indicator separately from the measuring head.

Swiss made Compac dial bore gages are among the finest measuring tools available. Years ago, they were also manufactured with the name Interapid, Alina and SPI. Except for the dial face, these were identical in every way. Old models varied slightly from the new models but all parts of the measuring head, including contacts and extensions are interchangeable. The dial indicator has changed substantially and you may have no option but to replace it with the new indicator (shown below) if it has sustained serious damage.

Replacement contact plugs, parts and extensions are also available from Long Island Indicator Service. The bore gage above is shown with the optional depth stop. See our Do-It-Yourself page for other instructions.

Dial Bore Gages consist of two sections. The measuring head (to the left in the illustration above) and the dial bore indicator (to the right). You can buy these separately, or as a complete unit. Be sure you are clear about what you're getting when you place an order.

Step 1: Compac dial bore gauge measuring head

To get a complete bore gage set, you will have to buy the measuring head (step 1) and the indicator (step 2).

With the measuring head you will also receive the wooden box and all the necessary contacts and extensions for that model. You will have to buy the dial indicator separately. It will not be possible to use any other kind or brand of indicator with this measuring head.

It should be pointed out that metric models are also available as well as all accessories and spare parts. If you're looking for metric bore gages, please see page 169

Special offer: since the manufacturer has been having difficulties with timely deliveries we are offering a 10% discount on any measuring head listed below which can not ship within 2 weeks of your order.

Although SPI no longer sells this bore gage, we include the old SPI ordering numbers for cross reference. The gages are identical with the exception of the name on the box.

Measuring head

Compac no.

SPI no.

Order no.

Sale Price

.150-.270"

IA00A

20-010-5

27947

3959.00

.270-.500"

IA0A

20-012-1

27949

1259.00

.5-1.0"

IA1A

20-014-7

27951

1469.00

.8-2.0"

IA2A

20-016-2

27953

1179.00

2-6"

IA3A

20-018-8

27955

1229.00

2-12"

IA4A

20-020-4

28015

1499.00

2-20"

IA6A

27959

3399.00

To complete your bore gage set, select one of the dial indicators shown in Step 2 below.

You may place orders online by selecting any linked number.

Step 2: Bore gage dial indicator

To complete your bore gage set, select one of the following dial indicators.

The indicator is interchangeable with the different heads. For example, you'll need indicator model IAP555A (shown below) for all measuring heads above .5" (IA1A, IA2A, IA3A and IA4A).

You can save money by buying several size heads but just one interchangeable indicator.

If you own a very old model, perhaps an Alina or Interapid bore gage, you can also replace the old indicator with this new one. This comes in handy since repair parts are no longer available for those old models.

Compac model IAP555A

This indicator is specifically designed for use with the Compac bore gage. Notice the set screw in the photo above? Hand tighten this to attach the measuring head. You wouldn't believe how many people ruin the threads by tightening with wrenches and the like.

It will not be possible to substitute any other indicator. For all gages measuring less than 2 inches, the indicator will range ± .020 inches. For gages measuring more than 2 inches, the indicator will range ± .070 inches.

Why are there two different zeros for the small "tell-tale" hand? It's because this same indicator is used for several different ranges. On ranges under 2 inches, only the short range zero on the lower left of the inner dial will be used. On larger ranges, the zero to the right will be used.

Model

Order No.

Graduations

bezel color

for this range

Your Price

IAP555A

27967

.0001"

red

.500" to 20.0"

499.00

IAP543A

27965

.0005"

blue

.500" to 20.0"

469.00

IAP365A

27961

.0001"

chrome

.160" to .500"

459.00

IAP367A

27963

.00005"

chrome

.160" to .500"

509.00

You may place orders online by selecting any linked number.

Small bore replacement heads

The smallest bore gage (.16-.26") consists of 6 small measuring heads. These can also be bought individually, without a box, indicator or accessories. All you need is an indicator (IAP365A or IAP367A) as shown above. Metric models are also available. Wooden box #042399 is separately available to store all these measuring heads.

Measuring head only

Part no.

Order no.

Your Price

.150-.170"

IA00A011

044065

639.00

.170-.190"

IA00A012

044066

639.00

.190-.210"

IA00A013

044067

689.00

.210-.230"

IA00A014

044068

689.00

.230-.250"

IA00A015

044069

689.00

.250-.270"

IA00A016

044070

689.00

You may place orders online by selecting any linked number.

Measuring depth

• .150"-.270" gage minimum: .020" maximum: 1.625"
• .270"-.510" gage minimum: .120" maximum: 2.375"
• .500"-1.00" gage minimum: .200" maximum: 3.500"
• .800"-2.00" gage minimum: .320" maximum: 4.750"
• 2-6" and 2-12" gages minimum: .360" maximum: 8.750"
• extension RI-100 adds 4" extra depth to .5-1.0" and larger gages
• a maximum of two extension RI-100 may be used to add 8" extra depth
• special extensions to reach 20", 30", 60" and 80" are available on request. They will require use of dial gage 555AIA (.0001") with the bore measuring head.

All the above have metric equivalents.

Compac, SPI and Interapid

COMPAC instruments were also distributed with the SPI name on test indicators and bore gages, or the INTERAPID name on dial bore gages. It's a rarity to find the Tesa or Alina name on the dial, but it does exist. Long Island Indicator Service stocks all parts used to repair these gages. The only difference is the dial, and these we don't have. (But you can replace the dials with the appropriate COMPAC dials.)

Repairs and spare parts

If you already own one of these bore gages, you know that they were the very best available. Take extra good care of them! (They don't make 'em like they used to.) And, if they need repair, Long Island Indicator Serivce is an authorized repair facility for Compac and Interapid dial bore gages. Because we have all repair parts in stock, and years of experience - including factory training in Switzerland - these tools can be repaired in just a few days. They'll be rebuilt to meet the manufacturer's original specifications. Your satisfaction is guaranteed.

Virtually every Compac and Interapid spare part is always in stock and can be shipped immediately. Large orders may require 4-6 weeks. There are no minimum purchases required. Parts lists are available online. See Spare parts lists.

Regular indicator vs. bore gage indicator

The Compac and Interapid bore gage indicator and the regular dial indicators may have the same model number, but there are some internal differences, as well as the obviously different case. The letters IAP identify the indicator designed for use with the dial bore gages. For example: IAP555A is the bore gage indicator, while 555A is the standard dial indicator. This distinction must not be overlooked when ordering parts.

Converting your 6" into 12"

It's possible to extend the range of your 2-6" dial bore gage (model IA3A) and convert it to 2-12" (model IA4A) by adding the following items:

• 044138 extension C with screw
• 041915 extension D
• 044139 large sled (steel) or 044140 (carbide)

Your model IA3A box already has provisions to store these extra items.

Online purchasing and current prices can be found in the spare parts lists for this bore gage.

New Compac Red and Blue Bezels

The old style bezels and associated parts are no longer available: specifically the chrome bezel (#530-71), the tolerance markers (#530-80), the ring with crystal (#530-78) and the retaining ring (#530-082).

As of October 1993 these parts were replaced with a color coded bezel and a snap-on crystal. It is possible for repair shops to replace the old with the new.

Dial indicators series IAP500 for the Compac and Interapid dial bore gages require the following:

• bezel (blue) .0005" #041950
• bezel (red) .0001" #041952
• snap-on crystal #041329
• tolerance marker L #041451
• tolerance marker R #041452
• O-ring for crystal #042257

The chrome bezels for IAP365A and IAP367A have not changed.

Important calibration information

Compac and Interapid bore gages measure by comparison and therefore must be calibrated before use by means of one of the following:

• reference ring gage
• fork for slip gages
• masterpiece
• gap gage
• micrometer

To calibrate the bore gage, proceed as follows:

1. Push button in order to withdraw the movable contact and insert the measuring probes into the reference gage.
2. Seek the return point by oscillating the probe.
3. Turn the dial until the return point of the hand corresponds to the actual dimension of the ring gage.
4. Fasten bezel clamp screw.
5. Set the tolerance markers.
6. The instrument is ready for use.

Measuring Accuracy

The manufacturer does not supply any specifications for the accuracy of the bore measuring head because this gage is only used as a comparator; however, the dial indicators used in conjunction with the measuring head have the following accuracy:

IAP365A indicators:

.0001" accuracy

IAP367A indicators:

.0001" accuracy

IAP555A indicators:

.0001" accuracy

IAP365 indicators:

0,002 mm accuracy

IAP367 indicators:

0,002 mm accuracy

IAP555 indicators:

0,002 mm accuracy

IAP556 indicators:

0,002 mm accuracy

The bore gage indicator alone will have the same allowable total deviation (fges) as the corresponding dial indicators:

365A indicators:

fges = .00020"

367A indicators:

fges = .00020"

555A indicators:

fges = .00055"

365 indicators:

fges = 5 microns

367 indicators:

fges = 5 microns

555 indicators:

fges = 14 microns

556 indicators:

fges = 14 microns

How does it measure up?

And finally, how does the Compac dial bore gage compare to the competition? Take a look at page 8 and judge for yourself.

And, if you're interested in a less expensive but still good dial bore gage (also Swiss made) take a look at Tesa Veribor Light on page 208.