Tpactools DRO Calibration

[Hopsteiner]

The installation of my Tpactools DRO is finished. Now it seems comes the hard part, calibration. I’ve been going in circles. Either I’m missing something in the instructions or it’s the instructions. At this point, it doesn’t matter. If there’s anyone out there that is familiar with this unit, help would be appreciated. I’ve looked at you tube videos which have helped somewhat. I know I’m compounding my error in compensation, but can’t seem to reset to zero. I feel like a monkey pushing buttons and I think the monkey might have better luck.

 

[krypto]

From the factory, my mill DRO was right on the money compared to any standards I have in the shop. Are you sure you need to do this?

 

[RetNM]

From the factory, my mill DRO was right on the money compared to any standards I have in the shop. Are you sure you need to do this?

I agree!
If your machine is properly trammed and the scales are mounted parallel to the surface of each axis, you should be fine. A DRO will not correct errors of a bad/poor condition machine. Trying to do so, would be like a dog chasing its tail.

 

[Hopsteiner]

I’m all set now I found another video on You Tube, ToAuto linear compensation the easy way. It clarified everything. It’s dead on XY and Z. As they say a picture is worth a thousand words in this case a video. The ToAuto unit is almost a clone of the Tpactools unit.

 

[Sprocket]

I have the TPACTOOLS DRO on my mill. He makes the point that it needs to be calibrated. You then use the differences (measured vs known) to
adjust the DRO software. It's been a while since I did it, but it worked very well. I used a 1-2-3 block and DTI. Seems I took 5 measurements and averaged
It's very accurate and repeatable now. Adjustments were small, but necessary.
Doug

 

[Hopsteiner]

I have the TPACTOOLS DRO on my mill. He makes the point that it needs to be calibrated. You then use the differences (measured vs known) to
adjust the DRO software. It's been a while since I did it, but it worked very well. I used a 1-2-3 block and DTI. Seems I took 5 measurements and averaged
It's very accurate and repeatable now. Adjustments were small, but necessary.
Doug

Doug, thanks for taking the time to answer. It’s appreciated. I have done exactly what you mention. As with any piece of machinery, working with it brings knowledge. After a number of emails back and forth with Tpactools, I started to look at You tube videos. Now, most of the vids are of different units but there are similarities. One set of videos of a ToAuto unit looked interesting. And one particular video ”ToAuto calibration the easy way”. This one eliminated the math and works on the Tpactools. If you have the time take a look at it. I’m calibrated down to 5 places, more then accurate enough. Thanks for the response. regards Bill

 

[Hopsteiner]

I agree!
If your machine is properly trammed and the scales are mounted parallel to the surface of each axis, you should be fine. A DRO will not correct errors of a bad/poor condition machine. Trying to do so, would be like a dog chasing its tail.

Actually, that is the reason to use put a DRO on an old machine, to compensate for the wear.

 

[RetNM]

Actually, that is the reason to use put a DRO on an old machine, to compensate for the wear.

Your are absolutely correct! I guess my mind was on mapping ball screws where at times it seems to be a exercise in futility. Damn getting old and one's mind wanders in the wrong direction is aggravating.

 

[Harglo]

Hello
I have a phone number for the gent that sells the TPACtools in US. Stand by.
Harvey

 

[Hopsteiner]

Your are absolutely correct! I guess my mind was on mapping ball screws where at times it seems to be a exercise in futility. Damn getting old and one's mind wanders in the wrong direction is aggravating.

No problem, finally getting this calibrated was great. As we all know, Chinese manuals leave a lot to be desired. The You Tube video really made it easy. And Tom to his credit from Tpactools really tried to help me.

 

[Hopsteiner]

Hello
I have a phone number for the gent that sells the TPACtools in US. Stand by.
Harvey

Thanks Harvey, all is well. The deed is done. It’s all calibrated. My hair is growing back from where I was pulling it out.

 

[Hopsteiner]

From the factory, my mill DRO was right on the money compared to any standards I have in the shop. Are you sure you need to do this?

My mill is an M head from 1946. When I bought it from a guy at work, all I heard was Bridgeport. Many moons later and not getting any younger, I decided to rebuild it short of scraping the ways. I’m not that young. I put new screws, gibs, bronze nuts, welded up the table, where some idiot must have used a 30 inch wrench to tighten something down. Then I had the table ground. Did the painting and detailing. So, to get back to your question, after all of this work it was close, within maybe 3 thousands. But we all want closer, hence the investment in the DRO. Should I have bought a newer mill, probably. But… you get so far down a road and there you are.

 

[krypto]

You're missing my point, the DRO system should come from the factory with scales that are already much more accurate than .003" in the same way when you buy a digital caliper it arrives ready to use. The Easson GS30 scales that I installed on my mill have a worst case error of ±8μm over the entire scale range (550mm for the longest) which is ~.0003".

Each scale on my system has a QR code so you should be able to d/l the QC test report for the scale but of course the link's broken. I should have tried that back when I installed the scales. With that laser interferometer report you can go nuts and program non-linear error compensation but of course that's nuts because it's already more accurate than I need. I guess what you did is linear compensation. What accuracy specs does Tpac quote for it's scales?

The only time I've read about people DRO calibrating scales are when they replace or upgrade very old systems. It's difficult to accurately calibrate these scales as the best standards a home shop will likely have for calibration is stack of Jo blocks.