Q: I just tested a Compac 215GA. The movement through range is good, but the hysteresis in both directions (up or down) is .0003” or .0004”. Can you tell me what I should suspect is causing this huge error in hysteresis? I seem to have similar trouble with this indicator every calibration.
- Hysteresis should not be more than .0001” on this model. If the gages are new, then they should be returned for warranty repair. If not new, then I suspect that they are not being repaired correctly.
Q: I have a Compac 224GA for which adjusting the contact point angle seems awfully stiff. I am afraid of breaking the contact point off at its thread. I don’t see a screw for adjustment of that aspect. Is there an adjustment? Lubrication of the “brake claw” that appears to grip the contact pivot?
- The Compac contact point has more friction than any other manufacturer. It’s okay to use force to get it to move. They also have over-sized ball bearings which can take the torque. There are no screws, etc. and lubricating doesn’t really help. That’s just the way they are designed.
Q: After testing the .0001 test indicators we believe that the double swipe .0001 indicators just don’t read as true as the single revolution BesTest, for instance. Have you noticed similar results?
- It is quite true that the multiple revolution indicators are less accurate over the entire range (which is longer than the single revolution) and that the hysteresis error is more pronounced. This is due to the fact the these indicators have one or two more gears in them and each addition of a gear will understandably increase the error. You should not be tempted to use a multiple revolution indicator unless your application absolutely demands it. Staying with the one revolution indicator is preferable.
Q: I am interested in the Compac 213GLA test indicator. Your website said that some have had dials that were not printed very well, though, but also that Compac was your indicator of choice for 4 decades. Are the dials back up to snuff?
- The dial problem is sporadic and most often the dials are perfectly fine. You may need a magnifying glass to notice any defects. We tend to be overly critical in this respect, probably to our own detriment. (As of 2014, the dials seem to be in good shape.)
Q: What is the best way to preserve the dovetails in the long run on something like the Compac, with integral, non-hardened dovetails?
- The body, and dovetails, is brass with a hard chrome finish. If you do not over tighten the dovetail attachments you will not cause any damage. Should the indicator be ripped from its holder, then the dovetail will probably have an unrepairable gouge. Fortunately, the indicator has 3 dovetails and you can always switch to using one of the others.
Q: I want a quality dial test indicator where the dial hand always moves clockwise whether the point is pressed from either direction and no "reversing lever" to worry about. I also prefer .0005" graduations, 1.5" dial, and .060" movement or close to it. I was under the impression the Compac worked in this manner, but I was just told they work just like my interapid.
- Compac hands always go in just one direction (clock-wise) no matter how you deflect the contact point. There is no reversing lever to deal with.
For answers to these and many more questions please take a look at our new publication highlighted below.