Going nuts

[ltlvt]

I'm back at the well of knowledge again. I've been trying to calibrate my new TouchDRO and here is my problem. So far, I have only tried to calibrate the X axis. When doing so I have followed the prompts in the program I am using I-gaging scales and a Samsung Galaxy Tab4. As instructed, I am using 1-2-3 blocks and a dial indicator. I find the left side of the removable block and wait for it to do its sampling. Then i continue to the right side of the block and wait for it to do it's sampling. When prompted to do so I click on the apply button. Now comes the problem. I use the same 1-2-3 block to verify, and it reads 3.225 on the display. No way could I be off by .225. So, the question is what is wrong? When it cools down tonight, I will verify the scale using the battery-operated display that comes with the scale.

 

[Inferno]

What are you using to sample the edges? Would it be possible that the tip is .225?

 

[ycroosh]

I'm back at the well of knowledge again. I've been trying to calibrate my new TouchDRO and here is my problem. So far, I have only tried to calibrate the X axis. When doing so I have followed the prompts in the program I am using I-gaging scales and a Samsung Galaxy Tab4. As instructed, I am using 1-2-3 blocks and a dial indicator. I find the left side of the removable block and wait for it to do its sampling. Then i continue to the right side of the block and wait for it to do it's sampling. When prompted to do so I click on the apply button. Now comes the problem. I use the same 1-2-3 block to verify, and it reads 3.225 on the display. No way could I be off by .225. So, the question is what is wrong? When it cools down tonight, I will verify the scale using the battery-operated display that comes with the scale.

Are you zeroing out the DRO before you try to verify the dimension?

 

[ltlvt]

Are you zeroing out the DRO before you try to verify the dimension?

yes

 

[ltlvt]

What are you using to sample the edges? Would it be possible that the tip is .225?

no

 

[ycroosh]

yes

What CPI is the calibration giving you?

 

[ltlvt]

What CPI is the calibration giving you?

I will need to check it again to see. What should it be for a 3 inch block ?

 

[Makintrax73]

I will need to check it again to see. What should it be for a 3 inch block ?

I believe CPI is shorthand for the resolution of the scale, not the block used for calibration. For instance on 5um glass scales it will tell you that you have 5,084 steps per inch or something close to that. If you know the steps that your scales should have +/- and your calibration procedure produces something substantially different either the scales were improperly manufactured or you didn't calibrate the scales properly.

 

[RJSakowski]

I find the left side of the removable block and wait for it to do its sampling. Then i continue to the right side of the block and wait for it to do it's sampling.

When calibrating a DRO, you want to approach from the same side of the calibration block. I stack two blocks and zero on the first block. Then I remove the first block and move to the second block. It is also important to have the blocks square with the table to avoid cosine error.

 

[Inferno]

I believe CPI is shorthand for the resolution of the scale, not the block used for calibration. For instance on 5um glass scales it will tell you that you have 5,084 steps per inch or something close to that. If you know the steps that your scales should have +/- and your calibration procedure produces something substantially different either the scales were improperly manufactured or you didn't calibrate the scales properly.

I think this is where the problem is. He's using the calibration but not saving the units.
I recently found out my original measurement was wrong and my CPI was off by 2. It explained all of the errors I was having.
Since the difference is repeatable, the error must be in the scale calibration. If we had a screenshot of his CPI, we could probably do the math to get the right one.