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Long Island Indicator Service


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"We are open for business and prepared to repair your gages. Find out how. Thank you for your support."

Roy Meyer and team

Blake Co-Ax center locating indicator contact points

SPI Co-Ax (made in USA) and Blake Co-Ax are identical. Also known as Co-Axial indicators. Be sure that you have purchased the genuine made-in-USA Co-Ax and not a Chinese imitation (if they cost under $250 they're definitely Chinese). There is absolutely no reason to believe that Blake parts will function in the Chinese gages.

Spare parts are not available from us, but repair service is!

Bergeon Jeweler's Screw Driver Set

Quality repairs start with quality tools. We would not want to be without our Bergeon Jeweler's Screw Driver Set.

Ordering No. Style Ball Length Maximum diameter Price US$
851 straight steel Ø .125" 1.8" 4.25" 21.00 place order now
852 curved steel Ø .125" 1.8" 4.25" 21.00 place order now
852-C2 curved carbide Ø .125" 1.8" 4.25" 55.00 place order now
851-3 straight steel Ø .125" 3" 6" 36.00 place order now
852-3 curved steel Ø .125" 3" 6" 36.00 place order now
851-4 straight steel Ø .125" 4" 8" 36.00 place order now
851-C4 straight carbide Ø .125" 4" 8" 55.00 place order now
852-4 curved steel Ø .125" 4" 8" 40.00 place order now
852-C4 curved carbide Ø .125" 4" 8" 55.00 place order now
851-5 straight steel Ø .125" 5" 10" 40.00 place order now
852-5 curved steel Ø .125" 5" 10" 45.00 place order now
851-6 straight steel Ø .125" 6" 12" 40.00 place order now
852-6 curved steel Ø .125" 6" 12" 45.00 place order now
851-7 straight carbide Ø .125" 7" 14" 55.00 place order now
852-7 curved carbide Ø .125" 7" 14" 55.00 place order now
851-9 straight steel Ø .125" 9" 18" 85.00 place order now
851-10 straight steel Ø .125" 10" 20" 95.00 place order now


Straight feelers are used for inside diameters and curved feelers are used for outside diameters. They are easy to interchange. The maximum measurable diameter is twice the length of the feeler (with the exception of the standard feeler which will indicate a maximum diameter of 4.25 inches). Thus, a 3" long feeler can indicate a diameter of 6 inches, etc.

The 9" and 10" long feeler is suitable for working with tire rims indicating a maximum diameter of 18 or 20 inches. The manufacturer does not make this size feeler, so we have had them custom made. The manufacturer advises us that the gage should work correctly even with this size feeler extra long installed. However, we can not take any responsibility for the function of the indicator when non-standard feelers are used.

  • Standard ball diameters on these feelers is 1/8" steel. These are also available in carbide for certain lengths.

Repair Notes

Spare parts can be bought directly from the manufacturer. A parts breakdown is conveniently included with new indicators. We only offer replacement contact points as shown above.

Parts for the movement are not sold separately. It will be necessary to buy the entire movement #825.

Co-Ax body #803 comes with the bushings installed but it requires special fixtures for proper assembly and do-it-yourself repairs are strongly discouraged.

Shaft #841 is different in inch and metric Co-Ax indicators. It's the top, short end of the shaft diameter that is measured. The long end is the same for both types.

Pin #846 is a press fit into rocker #844. It will slide easily through the shaft. Choose two spacers of an appropriate thickness to eliminate side play. When tapping the pin into place take care not to bend shaft #841. Use some form of support to prevent damage. The straightness of this shaft is the critical element in the Co-Ax indicator's function. Two spacers will also be used under screw #863 and nut #864 to eliminate side play in that location.

The glass crystal #834 is .020" larger in diameter on the new models (1.465"). If you're trying to fit it into an old model, use a diamond file to modify it. The alternative is to replace the old bezel with a new style bezel so that the crystal fits. Old style crystals are not available.

The new style bezel #826 easily replaces the old style. It will, however, need the new crystal #834 (see note above).

Spacer #847 is used to eliminate sideways play. Trial and error will tell you which size to use, although we find that .004" is the most common in our repairs.

If you would rather have us repair these co-axial indicators for you, please click here for details.

Be aware that cheap Asian imitations also exist. There is no guarantee that these original Blake parts would work on the Chinese indicators.


Companion Reference Guide for Test Indicators
$19.50 Now available at

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