# 935 DRO Install Pics?



## petertha (Aug 7, 2018)

Maybe I missed it, but does anyone have some pics / writeup description of DRO installation on this mill? 
Of particular interest, the Easson 3 axis Mill DRO package offered at PM?
https://www.precisionmatthews.com/shop/pm-935droes12/


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## Alan H. (Aug 7, 2018)

Peter, 
My Easson 12B was installed by Matt and friends at QMT.   

Here are some photos of the scales, etc. albeit without the detail you may want.  Hopefully someone who installed one will also respond with more of the detail that you may need.  

If you need something more specific from me, I will see if I can get a shot of it for you.  

Z scale:






Y and Z scale:





Y Scale:











X Scale:





Readout and support arm:


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## petertha (Aug 7, 2018)

Very helpful, Alan, thanks. Very clean install.

- did the PM kit limit the travels much in any dimension?
- real dumb question but the Z DRO on these machines is always on the knee, never the quill? Do you have one of those digital vernier styles on the quill or just don't bother? This never even occurred to me. My current mill is an RF-45 bench style so this is what I kludged together.


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## Alan H. (Aug 7, 2018)

Peter,
No there are no travel limits inflicted on the PM935 mill by the Easson 12B DRO.

Regarding the Z axis, I believe it is always the knee.  There are DROs that also have a second vertical axis measurement for the quill.  Perhaps Mark @mksj  can comment on that since his Acra mill is equipped that way.

Another option that can used is a separate DRO Indicator Kit like Mitutoyo makes for Bridgeport style mills.
I chose that route and installed one my PM935:






Here is a thread discussing the install of a Mitutoyo quill DRO on my machine.


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## external power (Aug 16, 2018)

Alan,  I'm installing this system on my PM935 now and was wondering if you could post a couple of pictures of the x axis reader
under the cover. It would require removing two screws and if you didn't want to I would understand. 

Regards  Doug


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## Alan H. (Aug 16, 2018)

Doug, I will try to get to it tomorrow.


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## Alan H. (Aug 17, 2018)

Doug, here are the X photos you asked for.  Good luck with your install.


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## external power (Aug 17, 2018)

Alan, That is exactly what I needed to see, Thanks so much.  Doug

I see you're from my home area of Baldwin county, Man I sure miss the Gulf Coast


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## Bob Korves (Aug 17, 2018)

petertha said:


> - did the PM kit limit the travels much in any dimension?


From whatever source, scales may be purchased in various lengths to fit different applications.  The manufacturer/seller will tell you how to measure for that brand of scales.  It is very important that the length of travel is long enough so the read head never can crash at the ends of its travel.  If the scale travel is shorter than the axis travel, there is an accident waiting to happen.  Scales with a longer travel than the axis travel do not cause a problem unless there are physical constraints to the mounting areas on the machine, other stuff getting in the way.  Also, if you have an axis travel of 20" and buy a scale with 20.1" travel, it will work, but you will play hell mounting it accurately enough to not crash at one end or another, and it is difficult to mount to those tolerances.  Give yourself an extra inch or two minimum when there are no other mounting constraints, it will make life much easier when mounting the scales.  I ordered the scale travels for my mill 50mm longer than the maximum travel of the axes.  

One more thing.  Do not use the manufacturer's published numbers for travel when ordering scales.  Measure the travel carefully yourself, making sure that travel stops and other temporary restraints are not limiting the maximum travel of the axes.


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## Alan H. (Aug 17, 2018)

Bob Korves said:


> From whatever source, scales may be purchased in various lengths to fit different applications.  The manufacturer/seller will tell you how to measure for that brand of scales.  It is very important that the length of travel is long enough so the read head never can crash at the ends of its travel.  If the scale travel is shorter than the axis travel, there is an accident waiting to happen.  Scales with a longer travel than the axis travel do not cause a problem unless there are physical constraints to the mounting areas on the machine, other stuff getting in the way.  Also, if you have an axis travel of 20" and buy a scale with 20.1" travel, it will work, but you will play hell mounting it accurately enough to not crash at one end or another, and it is difficult to mount to those tolerances.  Give yourself an extra inch or two minimum when there are no other mounting constraints, it will make life much easier when mounting the scales.  I ordered the scale travels for my mill 50mm longer than the maximum travel of the axes.
> 
> One more thing.  Do not use the manufacturer's published numbers for travel when ordering scales.  Measure the travel carefully yourself, making sure that travel stops and other temporary restraints are not limiting the maximum travel of the axes.



Good advice Bob but the OP is talking about buying it from QMT/Matt.  That's the beauty of buying the Easson package from them, they'll send you what you need.


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## dfsmoto (Aug 18, 2018)

I see the advantages of getting it through PM but I went the straight from China route.  The brackets are all worthless and the covers are bulky.  But Hey for about $400 less its going to work ok.  Just having to use the mill you are installing it with the whole time is a trick!


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## external power (Aug 21, 2018)

My install is complete and she works like a charm best I can tell. Only wondering how and where they
stash the power supply on the 935 install


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