# Lathe DRO uses X and Y, instead of Z and Y



## andrewgr (Jun 19, 2021)

I got the DRO pre-installed by PM on my 1340Gt.  I believe it was one of the first ones that used their newest model DRO.  

It accepts input into its X and Y ports; the Z port is not installed and just has an empty housing where the port would be.

It's not a big deal to pretend the X is a Z, but it does make the Z+Y function useless (I have no idea if I'd ever want to use this functionality).  Also, it offends my minor OCD. 

Is this the way most lathe DRO's work?  Is it expected?  And are there any other downsides between the two minor ones I mentioned above?

Thanks in advance.


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## rabler (Jun 19, 2021)

That happens as many DROs are designed to be useable on either a mill or lathe.  (+) functionality is only useful where two devices are or can be in the same direction, like a mill quill and knee, or a lathe carriage and tailstock.  With only two axis there is no real good use case for that


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## darkzero (Jun 19, 2021)

It's because most DRO displays being sold are "universal" displays, for use with mills, lathes, & grinders. The "Z port" that you are refering to is empty on a 2 axis display. It's present on a 3 axis display & would be displayed as the 3rd axis.

Not very many vendors offer lathe specific DRO displays due to selling/inventory reasons but they do exist. I have a lathe specific display. A lathe specific display won't have all the mill functions which are pretty much useless on a lathe. Lathe specific display will also have a button to quickly toggle from radius & diameter mode for the X axis, although many of the universal display have this button now. And of course they're labeled correctly for the Z axis.

Nothing wrong with using a universal display unless you have really bad OCD and the Y/Z label bothers you. BTW, on a lathe it's X & Z, not Y & Z. When using a universal DRO display (or any display actually), X should be connected to the cross slide, top/1st axis on the display, Carriage (Z) should be connected to "Y", the second axis on the display. Reason being, if your DRO display has the radius/diameter mode toggle button, it only works for the 1st/top X axis.







(Actual Y axis on a lathe would be a milling attachment)


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## MrWhoopee (Jun 20, 2021)

I intentionally set mine as x=carriage feed, y=cross feed. From my point of view (which is the only one that counts), it's the same on both lathe and mill. I don't lose any sleep over it.


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## erikmannie (Jun 20, 2021)

I have purchased 2 lathes from PM with factory installed DROs. I noted which is the cross slide display (top) & which is the carriage display (bottom). Once I identified which is which, I started work using the DROs. 

Interestingly, I *never* use the (analog) dials on the cross slide & carriage handwheels. The only time I look at these when I’m cleaning them.


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## Christianstark (Jun 21, 2021)

The Magexact has X&Z. The newer glass scale DRO's they show on the website is labeled X and Y/Z.


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## Janderso (Jun 21, 2021)

erikmannie said:


> Interestingly, I *never* use the (analog) dials on the cross slide & carriage handwheels. The only time I look at these when I’m cleaning them.


I can see why, I'm the same way using the mill. DRO's are amazing. I would love to have one on my lathe.


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## MrWhoopee (Jun 21, 2021)

Janderso said:


> I can see why, I'm the same way using the mill. DRO's are amazing. I would love to have one on my lathe.


Jeff,
In the world of machining, a DRO is probably the most bang for the buck that you can get. Take a gamble, drop a couple hundred bucks. I'm sure you've spent more and gotten less.


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## Janderso (Jun 21, 2021)

MrWhoopee said:


> Take a gamble, drop a couple hundred bucks.


??
I haven't found anything under $500.
A question on a lathe DRO.
I cant remember what you call it, when I move my cross slide .010" on the dial, it moves .005"
With a DRO, if you are trying to hit a dimension by removing .012", do you dial in .006"?
Is there a setting or a way to read like my lathe example with a DRO? Is that clear as mud?


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## Christianstark (Jun 21, 2021)

There should be a diameter/radius setting.




Janderso said:


> ??
> I haven't found anything under $500.
> A question on a lathe DRO.
> I cant remember what you call it, when I move my cross slide .010" on the dial, it moves .005"
> ...


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## RandyWilson (Jun 21, 2021)

Have Sharpie, will travel.


I just picked up a 3 axis SNS with scales for $170 delivered.


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## MrWhoopee (Jun 21, 2021)

Janderso said:


> ??
> I haven't found anything under $500.
> A question on a lathe DRO.
> I cant remember what you call it, when I move my cross slide .010" on the dial, it moves .005"
> ...


Ah, yes, you would need a scale over 1000 mm length. Prices jump significantly at that point. I do find a 1300mm scale for $120, making it quite possible to come in under $300.








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You are referring to radius/diameter reading.  I set mine for diameter (direct reading) so it reads the same as the dial. Crank in .010, it removes .010 from diameter. Much less likely to make a mistake.


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## andrewgr (Jun 21, 2021)

darkzero said:


> It's because most DRO displays being sold are "universal" displays, for use with mills, lathes, & grinders. The "Z port" that you are refering to is empty on a 2 axis display. It's present on a 3 axis display & would be displayed as the 3rd axis.
> 
> Not very many vendors offer lathe specific DRO displays due to selling/inventory reasons but they do exist. I have a lathe specific display. A lathe specific display won't have all the mill functions which are pretty much useless on a lathe. Lathe specific display will also have a button to quickly toggle from radius & diameter mode for the X axis, although many of the universal display have this button now. And of course they're labeled correctly for the Z axis.
> 
> ...



Thanks for correcting my x/y confusion!


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## erikmannie (Jun 22, 2021)

Janderso said:


> ??
> I haven't found anything under $500.
> A question on a lathe DRO.
> I cant remember what you call it, when I move my cross slide .010" on the dial, it moves .005"
> ...



Other than changing from metric to Imperial, I didn’t change my factory settings. If I want to reduce the diameter by .050”, I dial in .025”. You get used to this really fast.

I would prefer it like this, anyway, because the tool is moving in .025” (in the example above). It would be way more confusing to me if the DRO was reporting double the distance traveled.


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## Cletus (Jun 22, 2021)

BTW IMHO, the best Machinists and Engineers are OCD or some level thereof.  It's that attention and demand for detail that sets them apart!


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