# How to sum two iGaging scales



## patpend (Sep 19, 2013)

I have a two axis DRO on my mill and looking for a cheap solution to add a Z axis readout.  I'm thinking to install two iGaging scales, one on the quill and one on the knee. Does anyone sell a summing adapter that adds the quill and knee readings into a single Z-axis readout?   Or perhaps have an idea how to make one?  

http://www.grizzly.com/products/0-6-Digital-Fractional-Horizontal-Vertical-Remote-Scale/T21577
http://www.grizzly.com/products/24-Remote-Digital-Readout-Inch-Metric-Fraction/T23013


Russ

PS: I know this is not a CNC question but this seemed to be the best place to ask.


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## pestilence (Sep 19, 2013)

This project appears to be able to do it if you build the non arduino version.  I don't have a quill scale, but I will be building the correct version.  Maybe I'll add the fourth scale and let you know how it turns out.

http://www.yuriystoys.com/p/android-dro.html?m=1#msp430_1


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## PurpLev (Sep 20, 2013)

for the record in reference to operating a mill, you don't really have to use anything to add/subtract Z table axis and quill travel. These 2 should stay independent. I have yet to see any reason (nor see anyone ever) to use both quill travel and Z axis travel during machining of a part. Usually you will use the quill for setting up tool height, Zero Z axis, and use Z axis for milling height from that point on. Or use the quill readout for drilling holes to certain depth - but then again, you would probably want to use a depth stop for that purpose which will be more useful than a readout.

just adding more context, nothing more  . food for thought.


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## ycroosh (Sep 22, 2013)

PurpLev said:


> for the record in reference to operating a mill, you don't really have to use anything to add/subtract Z table axis and quill travel. These 2 should stay independent. I have yet to see any reason (nor see anyone ever) to use both quill travel and Z axis travel during machining of a part. Usually you will use the quill for setting up tool height, Zero Z axis, and use Z axis for milling height from that point on. Or use the quill readout for drilling holes to certain depth - but then again, you would probably want to use a depth stop for that purpose which will be more useful than a readout.
> 
> just adding more context, nothing more  . food for thought.



Sharon,
For the record , I ended up summing up quill and head (I have Sieg X3 mill, so no knee) positions to save screen real estate, primarily. (That way I didn't have to use two lines to display Z1 and Z2). With that said, I find myself using both a LOT now (mostly with smaller mills). I get the position "close enough" with the quill and then dial in the last few .001" using the "crank" (newer X3s have' finer Z axis lead screw, so it takes a lot of cranking to move the head up and down). With repeatable tool holders this might be even more useful, since no matter what you move your reference stays the same...

Regards
Yuriy


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## patpend (Oct 5, 2013)

Thanks gentlemen for the input.  I'm brand new to using a mill so I'm still sorting out what I think I want from what I actually need.


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