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WTK Good DRO for PM 835s

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chiroone

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#1
Now that I have the PM 835 I realize I really should have gotten the DRO pre installed. But since I did not, Looking to add now. Does anyone have suggestions for the DRO? All feedback welcomed, but I Would prefer to hear from someone that has already done this to discuss what I will need to make for brackets and what length of the sensors you ordered.
 

RJSakowski

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#2
Now that I have the PM 835 I realize I really should have gotten the DRO pre installed. But since I did not, Looking to add now. Does anyone have suggestions for the DRO? All feedback welcomed, but I Would prefer to hear from someone that has already done this to discuss what I will need to make for brackets and what length of the sensors you ordered.
would look at DRO Pros. They have a variety of glass and magnetic scale DRO's at reasonable prices. Also a lot of good infromation.

If you want to go with a less expensive DRO, some of the ones shipped from China will provide glass scales systems at a discount but the customer service won't be as good.

On the cheap are the capacitive scale units but they don't have the resolution of the glass scales. Capacitive scales typically have 10 micron (.0004") resolution . Glass scales are available with 5 micron (.0002") or 1 micron (.00004") scales as are magnetic scales. The 5 micron scale should be sufficient for most mill work.

Readout features are another consideration. Most of the glass and magnetic scale readouts have features like subdatum points which act like the ABS/INC button on a digital caliper but permit up to 200 different settings. They also will have features like bolt circle location, linear hole location, and cutting arcs, The capacitive scale readouts are generally simpler in function although some like Yuriy's Touch Scale offer advanced features.

Going upscale, there are systems like Mitutoyo, Anilam, and AcuRite, Fagor, & Newall.

I have installed two Grizzly systems which are essentially the same as the Easson system sold by DRO Pros and a Touch DRO sysytem. All three perform to expectations with the oldest having been in service for 14 years. I did custom installs for all of mine, making my own brackets to optimize te location of the scales and minimiize any impact on machine function.

Were I to do it again, I would go with the Easson system, probably with 5 micron scales for the mill and 1 micron scales for the lathe..
 

chiroone

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RJ. Thank you very much for the feedback. I will look at all of those DROs you suggested. I am a little concerned about the installation, well I’m sure I can drill some holes and tap them. I am a little bit concerned about making the custom mounts and brackets. I’m not exactly sure what I’m doing, but I suppose if I look at what is necessary I could probably figure it out. What did you used to make the brackets, was it just some aluminum angle?
 

wrmiller

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#4
On my 935, I basically moved everything and measured to get the numbers for the amount of travel the machine would do.

Example: I moved the table as far left as it could go before running off the saddle. Made a mark with a sharpie on the front of the table aligned with the front left edge of the saddle. Then I moved the table all the way to the right and measured from the left side of the saddle to the mark on the table. That's my max x-axis travel. :)

I did similar measurements with the y and z axis to get the travels there. Then called Dro Pros (I've had four of their DROs and have never had any issues) and asked for their suggestions. Ended up going with magnetic scales as I liked the idea of being able to trim them to length. Not sure you can do that with glass scales.

As for brackets, I basically just made whatever I needed out of aluminum angle and other pieces I had available. Whatever machining was needed I did on my new mill. :)

The Dro Pros website has lots of pictures of customer installs, which is where I got my ideas from for mounting the hardware.
 

RJSakowski

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#5
RJ. Thank you very much for the feedback. I will look at all of those DROs you suggested. I am a little concerned about the installation, well I’m sure I can drill some holes and tap them. I am a little bit concerned about making the custom mounts and brackets. I’m not exactly sure what I’m doing, but I suppose if I look at what is necessary I could probably figure it out. What did you used to make the brackets, was it just some aluminum angle?
My machines were both mill/drills so the three axes were x, y, and quill. I used aluminum plate and angle for the most part. I modified the supplied scale covers to suit my needs. I mounted the x axis scales to the front of the machines using O1 flat stock and spacers so that the power feed and limit switches were still functional. The quill scales were the most challenging. On one, I used the depth stop qnd on the other a custom made clamp for the quill. I have a compplete set of SolidWorks files for the second, a Grizzly G0755. While not the same as your mill, it might give you some ideas as to how to proceeed. PM me if you wish to see them.
 

Bob Korves

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#6
Example: I moved the table as far left as it could go before running off the saddle. Made a mark with a sharpie on the front of the table aligned with the front left edge of the saddle. Then I moved the table all the way to the right and measured from the left side of the saddle to the mark on the table. That's my max x-axis travel.
That is exactly how to do it. The only thing I might add is to make quite SURE that you are seeing full travel. No stops set, no tight gibs stopping it, etc. If the scale ends up too short and the read head can crash into either end, it will at some point. Murphy's law...
 
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wrmiller

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That is exactly how to do it. The only thing I might add is to make quite SURE that you are seeing full travel. No stops set, no tight gibs stopping it, etc. If the scale ends up too short and the read head can crash into either head, it will at some point. Murphy's law...
I was an engineer for over 30 years, so I always take into account Murphy (we've been on a first-name basis for decades...). Therefor I always add a little bit of 'fudge factor' for those times when I absolutely have to do something I normally don't. Like run the saddle off the front of the knee for example. ;)
 

davidpbest

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#8
I have installed a few brands of DRO's on mills and lathes, including the DRO Pro's mentioned above, and other brands as well. If ease of installation is your primary objective, by far the easiest IMO is the Newall DRO with microsym scales simply because of their universal scale mounting system. The cost of a Newall DRO could be competitive with DRO Pro's if you use their DP500 with microsyn scales on X & Y and a Mitutoyo quill kit on the spindle. Here are videos showing both:


And here is a link to the Newall DRO pricing:

https://machinetoolproducts.com/category/newall-dp500-digital-readout-kits/

If you want a three or four axis kit that puts the quill or knee or both into the same DRO display, then a Newall solution basically doubles in price because you're forced into their more expensive DP700 or DP1200 system. In that case, DRO Pro's packages are much more cost effective, but your installation time for customization of brackets and such will go up.
 

chiroone

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#9
I spoke with Nathan at machine tool products, , their prepackaged Newell 500 DROs are not available in the travel that I need. On the PM 835S, the travel on the X, Y and Z axis are 23, 10 and 16 respectively. He tells me the model 700 is available with custom made scales but is relatively expensive. I’m almost kind of scared to ask how much. I guess I will give DRO pros a call and see what they can do
 

Kiwi Canuck

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Don't forget Matt at QMT sells DRO's including the Easson Brand.

He would know exactly what you need.

David.
 

chiroone

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I just spoke withMatt an hour or so ago. He gave me a quote a little under $500 for a three axis DRO for the PM 835. While they are glass scales, it’s at least half the price of the nearest competitor. I think I might just go for that one.
 

wvnitroman

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#12
My machines were both mill/drills so the three axes were x, y, and quill. I used aluminum plate and angle for the most part. I modified the supplied scale covers to suit my needs. I mounted the x axis scales to the front of the machines using O1 flat stock and spacers so that the power feed and limit switches were still functional. The quill scales were the most challenging. On one, I used the depth stop qnd on the other a custom made clamp for the quill. I have a compplete set of SolidWorks files for the second, a Grizzly G0755. While not the same as your mill, it might give you some ideas as to how to proceeed. PM me if you wish to see them.
I don't want to hijack this post but was wondering what you think of your G0755? Thanks, Kevin
 

navav2002

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#13
I don't want to hijack this post but was wondering what you think of your G0755? Thanks, Kevin
The g0755 is the same as the PM932m. I have a PM932 and love it!!
 
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navav2002

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Oooops..Double Post..Sorry
 

RJSakowski

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#15
I don't want to hijack this post but was wondering what you think of your G0755? Thanks, Kevin
I didn't have a chance to use it very much but from what little I did with it, I thought it was a decent machine. It and the G4000 lathe we bought at the same time are what convinced me to buy a G0602 lathe for myself.

The only problem that I recall was with the set screw used as a key for the R8 socket. It had worked in too far which prevented R8 tooling from being inserted. I removed the set screw and replaced it with a modified socket head cap screw which could be locked down and impossible to seat too far into the socket.
 
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