Just got the import coaxial indicator from Enco.
The main spindle on this thing, and thus the entire body, wobbles with a TIR of 0.020" at the lower end. In other words, the axis of the unit is offset (or bent?) from the axis of the stub that goes into the machine collet.
Is this a defect, or a feature?
--Remember what Gomez said when he saw his son for the first time: "It's an Adams!". It's an Enco! Next time buy quality, heh.
It sounds like it's unable to pull up all the way. This wouldn't hurt function as long as you take up that slack in use so the dial registers all motion, but it's a defect rather than a feature.
I seem to recall that the first one I got from the "old Enco" was defective. They replaced it cheerfully at no charge.
I took it apart and the rotating shaft part itself is what's off. This looks like a ground and polished rod, about 1/2" dia x 4" long.
I was thinking maybe it is supposed to be offset a bit to somehow guarantee some wobble to work with? The instructions aren't at all clear. But they're in Engrish.
You might think that. But it does seem to be a problem, because when the indicator probe is offset from the spindle axis, this adds a component to the indication that is not aligned with the X or Y direction, making it nearly impossible to zero in on the sweet spot. You are hunting around a two-dimensional space for a null, but without a monotonic slope to follow.
Essentially you are trying to zero out two different, independently (mis) aligned offsets at the same time, the spindle to the indicator, versus the spindle to the work, and the axes of table motion affect each differently. So no matter how I turn the dial body or twiddle the leadscrews, the last few thou won't disappear. You zero one axis, and the other unzeroes.
I have the same co-ax indicator, and it did not wobble in operation. The wobble is apparently a defect and not a feature but this may not affect operation as the body is stationary [although it does move up and down on the shaft] during operation.
Now the had part ...
I had used this indicator a total of 5 times in about as many months and when I went to use it the last time the indicator would not move unless the tip of the pointer was at least a inch away from center.
Disassembly showed the tip on the AGD1 indicator had snapped where it screwed into the indicator stem. Examination with a magnifier shows the typical gray matte fracture of a hydrogen embrittlement failure. Apparently the tip was hard chrome plated and never baked. I don't know if the indicator has a US standard
4X48 thread or some metric thread as I can't get the broken stem out. Anyone have a suggestion? (other than buying a Blake?)MY APOLOGIES.
This was all due to a bad R8 3/8" collet, not the indicator.
I was using an untried R8 collet that came with an old machine. Looks like the previous owner ruined it and just put it back in the set.
I 3-jaw chucked the indicator in the lathe, and the TIR was only 0.001, within the chuck's holding error.
If the shaft wobbles it is definitely defective. There is no perceptible play in mine. If I center on something that is round and smooth, as a ground endmill shank held vertical in the vise, the needle doesn't even quiver as I turn the mill spindle.
I bet they'll exchange it for a good one. They're very handy gadgets at times. I used mine today to center on a hole I wanted to make larger by boring but keep the same center.
I have no complaints about the Enco coaxial indicator. I can't say the same about their boring head as compared to a Criterion head. They look nearly identical but they sure don't work the same!
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