DRO for PM-25MV

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Steven57

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Have been researching and consensus seems to be that digital scales stainless are accurate enough for the mill. Anyone think otherwise as in glass/magnetic?

And while we are st it, what about PM-1030V? Stainless scales or full DRO glass/magnetic?
 
If you believe those are what you want, go for it. Who cares what everyone else thinks? :)

Just for the record, I use 3-axis glass. But that doesn't mean you should.
 
Actually, I was wonder who was using what and their real life experience. Statements like "I have the stainless and wished I had glass/magnetic" or "Stainless works great for me on this mill".
 
Ah, got it. :)

The glass 'might' be over kill, but who's to say? I really like mine and the accuracy I get from them. You also have to remember that different folks have different situations and will make do with what they can get/afford. For me, I would have loved to get the magnetic scales but just couldn't afford it (justify it?) at that time. Would the magnetic have been better? Don't know.

Another example: When I bought my first mini-mill 12 years ago I bought a small 3-axis DRO from a Canadian company that used toothed rods and gears for scales (sorry, can't remember the name off-hand but they still exist) and while I thought it was kinda funky from a design perspective the little stinkers actually worked quite well! :)

Point is, most of this stuff will work fine but it won't necessarily prevent people from wishing for something different. What are the goals you are trying to achieve with your machine/DRO setup? What kind of projects are you thinking of doing and what kind of accuracy are you trying to achieve?
 
Steven57 said:
Have been researching and consensus seems to be that digital scales stainless are accurate enough for the mill. Anyone think otherwise as in glass/magnetic?

And while we are st it, what about PM-1030V? Stainless scales or full DRO glass/magnetic?
Click to expand...


I chose to install DRO Pros 3 axis with glass scales. The model is the 3M, and and came with great support literature and appears to be good quality. I have not used it for very long, so cannot comment on service life. The readout has a number of useful features that I am still learning to use. It is a very intuitive system that does not require you to have the manual at hand every time you want to try out a feature.
 
Ideally I'd like accuracy to .001 and it seems that is doable even with the stainless digitals. Everything I intend to do would be just for me or friends and would generally be replacement parts, jigs, and a couple precision pieces I have in my head. As long as the screw/bolt holes line up I'm good with that. I understand the standalone 2-3 axis glass/magnetic systems have features/functions that the digitals don't. But, if I have my math down the digitals can get the job done.

So, after all of that I guess I'm asking are the stainless digitals accurate enough or not for the PM-25MV? Or, is the mill capable or not of reaching the accuracy of the glass/magnetic systems?
 
I have done half thou and less work on my PM25, which is more than I typically need as a hobbyist. :)

The trick with the PM25 or any of the smaller bench mills is to remember that these things are not very rigid and WILL flex as a function of how much load/cutting forces are placed upon them. When roughing in, you don't pay that much attention to part/machine flex other than to note how much in preparation for dialing in the next cut.

When you start getting close to your final dimensions, taking smaller cuts will reduce the machine/tool deflection (cutters flex too) and permit you to achieve your final dimensions without too much drama. To hold to a thou dimensional variance seems to be everyone's goal, but remember that even on a Bridgeport an experienced machinist doesn't try to hold any better than that (so I'm told). That's what surface grinders are for. :)

In my personal experience, I DO like to see those tenths on the readout (.0002) as that helps me 'fudge factor' for part/tool deflection as I'm sneaking up on final dimensions.
 
Can somebody provide a link to ''stainless digitals'', this is a term I've not heard before.
 
Stainless are more or less just a digital caliper with a remote read out. I have 3 axis igaging and they work awesome. I mean if it needs to be nuts on, you should not rely on a read out IMO no matter how much it cost. You can bout hit a .0001 on the stainless but it would be hit or miss I assume. It flash a half mark or something to that effect. But to stay in side a .001 or so, they work great.

But the functions in the real dros is where the money is at. That and the oil/coolant proof. As well as the .0001 reading as I I watch them when I get a thousandth over
 
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