Feelers

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" long feeler is suitable for working with tire rims indicating a maximum diameter of 18 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 (about 9" 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. Additionally, we have a 2" long feeler with a small 1/16" diameter steel ball. See the parts list above.

Repair Notes

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

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. 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).

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