Haimer 3D Taster repeatability

I wonder if those who use a Haimer 3D Taster could let me know what repeatability they're getting when touching off a zero and then rotating the spindle so the Taster is indicating the same surface but from different directions in respect the instrument (I hope that makes sense). So with the instrument facing you zero to a vertical surface to the right, zero the DRO, rotate the spindle 90 degrees (the Taster face will obviously now be to one side), touch off there and compare DRO readings, and so on to the back and then to the other side. I'm a little disappointed in mine lately and I don't recall ever being concerned about it before.

I broke a probe and replaced it, then adjusted it for concentricity. Then did the same for a second probe. I finished up making up a 23 mm pin spanner and pulling the whole Taster apart today and couldn't see anything at all that might lead to this sort of unreliability. Using a standard edge finder I can repeat to 0.01 mm no problem, but the Taster is at best only repeating to about 0.05 mm and just isn't giving me confidence in the readings. I've dicked around forever on the concentricity and feel it's about as good as I can get it.

Another method I used to indicate off the same surface was to touch off one, the butt a gauge block up against the surface and touch off the gauge block so it was on the opposite side of the probe. I haven't however tried that method since pulling the thing apart, so will try that tomorrow. The advantage with this method is nothing moves, and the probe simply goes from one side to the other so it pretty much isolates any chance it's sitting in the machine incorrectly etc.

You say you did adjust the probe tip for concentricity and still get .05mm variance? That's almost .002"

How are you holding the Taster in your spindle? Is this a manual machine or a CNC?

Mine is within .0005"

Pete F said:

I wonder if those who use a Haimer 3D Taster could let me know what repeatability they're getting when touching off a zero and then rotating the spindle so the Taster is indicating the same surface but from different directions in respect the instrument (I hope that makes sense).

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You need to approach the probe along a radius. If you merely rotate it against a surface, the sideways drag upsets the reading.

I don't think you're setting it up properly. Use these tips:

1. Spindle orientation should always be the same for calibration and all measurement. (orient the Taster so that M19 orients the gauge face for proper reading)
2. Use a gauge ring to calibrate....Start by sweeping the bore with an indicator to get your spindle on the gauge ring center. Now, you can calibrate for X+, X-, Y+, and Y-.
3. Optional, but this will allow you to get it to repeat better than .0005": use a toolholder with low runout...we use a hydraulic holder. You'll see the difference when you calibrate

If I change the probe tip on mine, I always calibrate it with an indicator and rotate the spindle by hand and adjust any

run out with the set screws. Adjust until reading zero on the indicator while I rotate the 3D taster.

Jeff

It's a manual machine.

Yes I found that Graham, you're quite right, but what I can do is as suggested above, back away from the piece and bring the tip back up to it at each point so it's effectively a new reading.

The Taster is being held in a 20 mm collet, but i think even if that was out (just for argument's sake), the adjustment for concentricity would account for that. I'm not removing it from the collet at any time after adjustment.

I've tried adjusting for concentricity two ways, the first is as instructed by Haimer, ie putting a DTI on the tip and rotating it so it's concentric. The other way is to do as above, approach a surface from 4 different directions by rotating the spindle, and adjusting the concentricity so it reads the same at each 90 degree point ie as close to zero as possible. However I'm never able to get it truly the same at each 90 degree point.

The only thing I was surprised about was there's a little 2 mm pin that locates the cone the probe screws in to. Yet the pin slides in a 2.5 mm slot in the cone (the cone looks like the end of a sphere if looking from the bottom), you won't see any of this if the rubber boot is in place. Is that correct? it struck me as a source of a bit of play there and I wondered if there should be a sleeve or something on that 2 mm pin?

I'll try to get some photos up tomorrow as it's night down here now and I've been going for 36 hours as it is. I love this thing and use it constantly so it's like losing a limb when I start to doubt it or it's clearly unreliable.

The easiest way is to use a ring gauge. That way, you are not trying to see round the back when it faces away from you. It also means you don't rotate the spindle.

If you have had your's apart, have you any idea how to set the absolute zero? When the tip is not deflected, the gauge should read the probe diameter (e.g. -2). Mine does not meaning I cannot set an edge to the gauge. Normally that is irrelevant as I am gauging each side of a hole to find a circular centre and the errors cancel out. The stop seems to be the edge of a plastic ring can't be right.

Graham Wright said:

The easiest way is to use a ring gauge. That way, you are not trying to see round the back when it faces away from you. It also means you don't rotate the spindle.

If you have had your's apart, have you any idea how to set the absolute zero? When the tip is not deflected, the gauge should read the probe diameter (e.g. -2). Mine does not meaning I cannot set an edge to the gauge. Normally that is irrelevant as I am gauging each side of a hole to find a circular centre and the errors cancel out. The stop seems to be the edge of a plastic ring can't be right.

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G'day Graham, I don't have a specific ring gauge, but I could use a bearing for the same purpose. I'll try that today, thanks (also to 'works above for the same suggestion).

To set zero on the dial, it appears the only way is to adjust the individual pressure on the 4 grub screws that hold the dial indicator itself in to the housing. If you look on the sides of the instrument you'll see them. They use a 1.5 mm key IIRC.

I'll try to get some photos up today for the benefit of others who may have problems with their Tasters in future. They're certainly a very simple device, and I think the price that's asked down here for them ($730, yes that's correct. Believe it or not), is quite steep considering what's in them. I had no reason to look in to the indicator mechanism, but from what I saw it didn't strike me as being especially well made, and looked like a standard dial indicator mechanism to me. The secret is in the cone mechanism, which seems to be just hard anodised aluminium, also nothing special.

Pete F said:

To set zero on the dial, it appears the only way is to adjust the individual pressure on the 4 grub screws that hold the dial indicator itself in to the housing. If you look on the sides of the instrument you'll see them. They use a 1.5 mm key IIRC.

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I may have used the wrong word. By absolute zero I meant the position the pointer returns to when not deflected.
The mechanism inside seems to stop rotating when the lever hits a plastic shroud. That seems pretty crude so maybe I am wrong. Rotating the dial would not achieve what I seek.

Graham Wright said:

I may have used the wrong word. By absolute zero I meant the position the pointer returns to when not deflected.
The mechanism inside seems to stop rotating when the lever hits a plastic shroud. That seems pretty crude so maybe I am wrong. Rotating the dial would not achieve what I seek.

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Yes that's correct Graham, the dial doesn't rotate, it basically "flexes" a little in the same position. I know it sounds very agricultural, and it is!

Just to be clear, if you want to adjust what the needle pointer reads when you're just holding the thing in your hand so it reads zero, just vary the tension on the screws as I described above. You may need to loosen the bottom ones a tad, while tightening the top ones, or visa versa. It doesn't take much to change the pointer position.

Pete F said:

Yes that's correct Graham, the dial doesn't rotate, it basically "flexes" a little in the same position. I know it sounds very agricultural, and it is!

Just to be clear, if you want to adjust what the needle pointer reads when you're just holding the thing in your hand so it reads zero, just vary the tension on the screws as I described above. You may need to loosen the bottom ones a tad, while tightening the top ones, or visa versa. It doesn't take much to change the pointer position.

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I understand now. The whole dial mechanism moves in relation to the probe pin. Unfortunately, mine needs more than that. It may have jumped a tooth (or two?!).

I have the digital taster and it's easily within .0002-.0003

Graham Wright said:

I understand now. The whole dial mechanism moves in relation to the probe pin. Unfortunately, mine needs more than that. It may have jumped a tooth (or two?!).

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Bit more info.
The pointer and its gearing appear to be connected to the shaft carrying the anti-backlash spring. It further appears that the gear on that shaft is held into engagement with the driving gear but can be lifted out of engagement by pulling away from the mechanism plate. The two gears can be disengaged and re-engaged thus. This allows coarse adjustment of the zero position.
I have detached the end of the spring from the shaft pillar and there is every chance I can't reassemble it!

Something tells me you will be sending that back to Haimer to have it fixed before this thread is finished up. They are not meant to be taken apart.

5 axis Fidia guy said:

Something tells me you will be sending that back to Haimer to have it fixed before this thread is finished up. They are not meant to be taken apart.

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Neither are dial indicators, and I've repaired dozens of them! However I agree something isn't sounding quite right there. Unless it was dropped badly, it does sound odd that it's just "skipped a tooth" because it was having a bad day. Yes you're correct in relation to the probe pin. You obviously have the whole thing out of the housing, so should be able to see how it all works. It's really quite a neat and simple device.

The cost of repairs to send it to Haimer and have them fix it means they are considered "disposable". on the other hand if it's just the zero that's incorrect you may want to just live with it. Having said that, I would expect it would affect the accuracy, and the indicator would be incorrect by the amount it's off to begin with.

I think either the indicator or the mill it in error and you should hastily give them to me for a fifty year evaluation to see if I can find which is in error..

RC99 said:

I think either the indicator or the mill it in error and you should hastily give them to me for a fifty year evaluation to see if I can find which is in error..

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No problem.

They come with operator

Pete I have the exact same problem. I broke the tip and after replacing it I am unable to adjust it for concentricity. If I just move in one direction to zero it and zero the dro, then it will always return to zero when the dro gets to zero as it should. But if I pull it back, rotate the spindle and touch it to zero, I will read anything up to 3 or 4 thou on the dro, and the errors are not repeatable as I keep rotating the spindle.
When I push the tip with my finger, I can feel some rough movement. I wonder if Haimer has a repair program, and how much it would cost.

yul m6 said:

Pete I have the exact same problem. I broke the tip and after replacing it I am unable to adjust it for concentricity. If I just move in one direction to zero it and zero the dro, then it will always return to zero when the dro gets to zero as it should. But if I pull it back, rotate the spindle and touch it to zero, I will read anything up to 3 or 4 thou on the dro, and the errors are not repeatable as I keep rotating the spindle.
When I push the tip with my finger, I can feel some rough movement. I wonder if Haimer has a repair program, and how much it would cost.

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Oh that's interesting. I'm not feeling any roughness, but it sounds like similar symptoms. I'm just finishing lunch and will get to work on the Haimer again now. I'll pull it apart again so I can take some lousy photos and post them here so those who may want to repair theirs have something to go on. I believe Haimer do indeed have a repair program, but I've been informed that by the time the thing is shipped there and back, plus their charges, it's not financially viable.