# Quill readout



## Clock work (Mar 17, 2018)

I see there is a healthy number of setups for instrumenting the quill and recently I've started to feel this would be useful. Big range on price.. not sure there's much of a range on delivery value/utility so I'm here to ask.. does anyone have a particular quit DRO they'd recommend? It seems as though it would just be TRIVIAL re: electronics to combine the Z-axis DRO with the quill selectively... when the operator wants to... to show a combined figure on the main DRO panel but I don't see this on the units I've looked at. Thanks in advance. 

CW


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## chips&more (Mar 17, 2018)

What kind of machine?


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## Clock work (Mar 17, 2018)

It's a PM-935. Does the machine type tend to make a difference? Just trying to learn something this month


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## Briney Eye (Mar 17, 2018)

Clock work said:


> I see there is a healthy number of setups for instrumenting the quill and recently I've started to feel this would be useful. Big range on price.. not sure there's much of a range on delivery value/utility so I'm here to ask.. does anyone have a particular quit DRO they'd recommend? It seems as though it would just be TRIVIAL re: electronics to combine the Z-axis DRO with the quill selectively... when the operator wants to... to show a combined figure on the main DRO panel but I don't see this on the units I've looked at. Thanks in advance.
> 
> CW


Yuriy's TouchDRO does that, and it's how I have my little Clausing 8520 mill set up.  It's a roll-your-own job, though.  I assume that at least some pre-packaged systems have the capability, but someone else will have to chime in on that.

ADDENDUM:  I just checked DROPros, and they sell "4-axis" mill kits that sum the quill and knee encoders, for about $1500.  Maybe their display heads all have the inputs for a four encoders.


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## mksj (Mar 17, 2018)

It is a common feature of the more costly/main stream DRO's (Electronica, Acurite, Newall,  etc.) usually in 3 axis in the lathe function and 4 axis mill. I use the axis summation  feature on the EL700.  These DRO's typically come in different axis configurations, some with digital numeric displays are mill or lathe specific, and also you need to order yours with the specific number of inputs. Inputs cannot be added at a later time, and the display keys often are specific to the number of inputs. So they do not all come with 4 inputs, and the cost goes up with each input.  I did check on some of the less expensive 4 input DRO's and did not see a summing menu function/setup (example below is the TPAC 4 axis).  There is a PC based 4 axis interface which does have this function, along with a few other setup features.
http://www.tpactools.com/4-AXIS-DRO...ORT-MILL-PACKAGE-ALL-4-GLASS-SCALES_p_55.html
https://www.machine-dro.co.uk/m-dro-pc-digital-readout-4-axis-interface.htm

There was some recent discussion on this topic this posting here: https://www.hobby-machinist.com/threads/pm-mill-accessories.67786/#post-568130 . The most common approach on a knee mill is going with a 3 axis DRO with the 3rd axis on the knee, and a battery operated quill DRO. Trying to mount a 4th axis DRO scale on the quill can be a bit more challenging, in particular a glass scale. I leave my mill DRO in summation of the Z and U axis, it is helpful, but not a deal breaker. There were other features of the EL700 that I wanted, along with the magnetic scales.
https://www.hobby-machinist.com/threads/quill-dro-for-a-pm935.60162/#post-515715


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## Clock work (Mar 17, 2018)

Gentlemen... I thank you. My machine already has a 3-axis DRO on it from Esson via PM. I very much like it. I've seen these smaller independent units that frankly look like someone repurposed a digital caliper to track quill drop and this is what I'd like to add. I see they range from high-$ Mitutoyo down to import stuff at vending machine prices though I don't see high-$ paying off for a repurposed digital caliper. 

As to functionality for "combining the z-axis", it feels as though it would be a very simple matter to add something in the path to allow operator-selected input to the DRO regarding what it shows on Z:

1. Z-axis
2. Z-axis "+" quill

Long time since I drew an ASCII diagram but....

quill scale -----------> combiner ------------> z-axis input to DRO
Z-axis scale ------------- ^

Seems pretty simple.. like something I'd have given as a homework assignment when I was teaching digital design even. So simple one of my students could do it. Maybe 2... ROFL!

CW


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## Bob Korves (Mar 18, 2018)

Clock work said:


> Gentlemen... I thank you. My machine already has a 3-axis DRO on it from Esson via PM. I very much like it. I've seen these smaller independent units that frankly look like someone repurposed a digital caliper to track quill drop and this is what I'd like to add. I see they range from high-$ Mitutoyo down to import stuff at vending machine prices though I don't see high-$ paying off for a repurposed digital caliper.
> 
> As to functionality for "combining the z-axis", it feels as though it would be a very simple matter to add something in the path to allow operator-selected input to the DRO regarding what it shows on Z:
> 
> ...


The only ones I have seen for sale require that both scales are quadrature, which means glass scales and perhaps magnetic.  The caliper type and the iGaging and Accuremote scales use a different protocol.


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## Clock work (Mar 18, 2018)

Thanks.. so some of these are for sale... I looked but unsuccessfully. Back at it.. 

It was a surprise to hear the application potentially being up-complicated to use quadrature communication/modulation and did some looking.. The pulse trains are certainly offset in a manner reminiscent of quadrature modulation but I can't imagine anything is gained by actually using that. All the application needs is to count the pulses on the two channels (or just one actually) and pay attention to who peaks or zero-crosses or whatever first to establish direction. I have the iGaging caliper (which I can highly recommend for accuracy, repeatability and build quality) and did some looking into its digital output last year. It appears to encode the position value so all the pulse counting is internal. I think if I recall it's SPI or possibly I2C. It's feeling attractive right now to build a simple 2-port combiner though first I'd definitely want to probe the output of the glass scales and ensure my understanding (simple pulse counting via 90-deg-offset signals) is the case rather than combined with quadrature. I totally need yet another project 

What kind of boat are you on in that picture if I can ask? Been under that bridge once and did not enjoy the chop even slightly. 

CW


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## Bob Korves (Mar 18, 2018)

Clock work said:


> Thanks.. so some of these are for sale... I looked but unsuccessfully. Back at it..
> 
> It was a surprise to hear the application potentially being up-complicated to use quadrature communication/modulation and did some looking.. The pulse trains are certainly offset in a manner reminiscent of quadrature modulation but I can't imagine anything is gained by actually using that. All the application needs is to count the pulses on the two channels (or just one actually) and pay attention to who peaks or zero-crosses or whatever first to establish direction. I have the iGaging caliper (which I can highly recommend for accuracy, repeatability and build quality) and did some looking into its digital output last year. It appears to encode the position value so all the pulse counting is internal. I think if I recall it's SPI or possibly I2C. It's feeling attractive right now to build a simple 2-port combiner though first I'd definitely want to probe the output of the glass scales and ensure my understanding (simple pulse counting via 90-deg-offset signals) is the case rather than combined with quadrature. I totally need yet another project
> 
> ...


Here is a commercial quadrature version:
https://www.machine-dro.co.uk/m-dro-linear-encoder-summing-interface.html

The thumbnail photo is taken under the Golden Gate bridge.  One of my old sailplane buddies is now an active instructor at a sailing school in Richmond, and I "crew" for him sometimes, fun way to get some different scenery in my life.  The boats we take out are in excellent condition, typically 36-42 feet long cruisers.  When I put up my photo here, nothing I had handy seemed appropriate or made me happy, so I just put up a sailing one.  Pilots who have flown sailplanes hard for decades do not care much about a few swells and chop.  At certain times under the Golden Gate, the transitioning tide along with the mostly onshore winds can make for some interesting sailing...


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## 4ssss (Mar 18, 2018)

:)

What kind of boat are you on in that picture if I can ask? Been under that bridge once and did not enjoy the chop even slightly.

CW[/QUOTE said:
			
		

> That's the reason only a few escaped Alcatraz.


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## Clock work (Mar 18, 2018)

Bob Korves said:


> Here is a commercial quadrature version:
> https://www.machine-dro.co.uk/m-dro-linear-encoder-summing-interface.html
> 
> The thumbnail photo is taken under the Golden Gate bridge.  One of my old sailplane buddies is now an active instructor at a sailing school in Richmond, and I "crew" for him sometimes, fun way to get some different scenery in my life.  The boats we take out are in excellent condition, typically 36-42 feet long cruisers.  When I put up my photo here, nothing I had handy seemed appropriate or made me happy, so I just put up a sailing one.  Pilots who have flown sailplanes hard for decades do not care much about a few swells and chop.  At certain times under the Golden Gate, the transitioning tide along with the mostly onshore winds can make for some interesting sailing...



Thank you again Bob.. a little more digging leaves me convinced the sellers of these extremely simple things are aggrandizing the technology. Sure.. the signals are "in quadrature" to each other which is a way of sounding like an RF engineer (very analog... high skills) in a digital application. It's just simple pulse counting.. no other connection to the concept. There's this example from my life that always springs to mind when I hear someone shoveling nomenclature... it was the 80's and I was looking at a pretty nice amp in a stereo store... semiconductor.. no tubes. Now, I'm sure I was dressed like a total dirtbag as is my tendency and that might have made him feel good about trying to close me by bragging about its industry-leading inter electrode capacitance. A term of art pertaining to tube gear though I should have not been so quick to judge him as maybe he was working on a PhD in electrical engineering too... LOL. 

Yup.. those were the conditions we encountered. I flew out to SF to join in a celebration on a boat with some people I was working with but my flight got in late and they already  headed out. Two guys in a Boston Whaler at the pier getting ready to go fishing literally from my exact town in NE offered to take me out. The water was smooth and we headed north to transfer me over. Caught em with the wind coming in under the bridge while the tide was ebbing and we got 4' waves just as we got near them Like.. flip a switch and the violence meter goes to zero. You could see the department's secretary throwing up as we approached Though perhaps it is immodest to attribute that to the conditions. I waved as I said "screw it" in my head about transferring in that chop, and went up to my favorite Italian restaurant up in the city to eat alone. And alive! 

CW


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## wcunning (Apr 8, 2018)

I've been looking for a DRO for my Rockford MV-100 for a bit now, and I was thinking about buying this box: https://www.sra-measurement.com/m-dro-linear-encoder-summing-interface.html. 

It's a summing box for two scales, and you can set +/- to get the distance from quill to table if you want. 

My unfortunate problem is that the Easson sellers on Aliexpress aren't responding, but I do *not* want to pay the money for an Acu-Rite or a Newall... Someday I'll come to a decision.

Cheers,
Will


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