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Thread: DRO for a lathe

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  1. #1
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    Default DRO for a lathe

    I have a 12 X 36 Grizzly lathe I would like to put a DRO on could someone give me an idea of which size is best? I did not want to hijack the other thread. Also explain what 1um 5um 10 um is as it relates to readout. Any help would be appreciated.
    Last edited by rolland; 01-10-2019 at 07:15 PM.

  2. #2
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    Quote Originally Posted by rolland View Post
    I have a 12 X 36 Grizzly lathe I would like to put a DRO on could someone give me an idea of which size is best? I did not want to hijack the other thread. Also explain what 1um 5um 10 um is as it relates to readout. Any help would be appreciated.
    DRO Pros. very happy with mine on McGrizzled lathe. Magnetic cut to size.
    www.cosmos-industrial.com - Pen Marking Tools for CNC machines

  3. #3
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    I went with DRO Pros when I put a DRO on my 10K South Bend. The amount of info on their web site is astounding. I am putting a DRO on my RF45 mill. I bought a cheapo on Amazon. There was near zero info on installation. If I had not done a DRO previously I would be lost.

  4. #4
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    You want the 1um scale for the crosslide. It will read in 1 or two tenth increments directly. Double that in radius mode. So basically you can work to half a thou with the 1um scale or 1 thou with the 5um.

    On the carriage ( long scale), 5um is fine and will read half a thou.

  5. #5
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    Yes, 1um on the cross slide!

  6. #6
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    Quote Originally Posted by rolland View Post
    I have a 12 X 36 Grizzly lathe I would like to put a DRO on could someone give me an idea of which size is best? I did not want to hijack the other thread. Also explain what 1um 5um 10 um is as it relates to readout. Any help would be appreciated.
    Size? as is travel length or "normal" size scales or miniature magnetic scales?

    For typical 12x36 lathe the miniature magnetic scales are lot easier to mount to cross slide than "normal" size glass/optical scales. Z axis(carriage) scales are easy to mount even if they are the thicker "normal" size.

    Needed travel length is best measured from your lathe, cross slide probably ~8 inches but even considerably longer scale might be ok for mounting. 1um resolution preferred but even 5um would be lot better than nothing at all.
    carriage scale at least 36", carriage might actually have more travel distance than your nominal 36" CC-length. Depending on lathe there is space to mount even 20" extra.

  7. #7

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    Only magnetic scales would work on my cross slide, even then I had to modify the cover. Go with Dro Pros they are very helpful!


    Here you explanation for Dro Pro's website:
    “Diameter Mode Dilemma” is a term used to refer to the loss of resolution on a lathes cross slide, or X axis. This ‘phenomena’ is particular only to a lathes cross slide, and does not occur on the carriage axis (Z), or for that matter, any axis of a milling machine or any other mechanical machine. Why then, does this only occur on the cross slide of a lathe? This is because the cross slide is unique, in that it removes material from both sides of a workpiece at a rate of 1:2, meaning that for every 1 unit of cross slide advance, 2 units of material are removed from the workpiece. In other words, if the cross slide is moved .004” into the workpiece, .008” of material is actually removed from the part. This forms the first part of the dilemma: do you measure the cross slide movement, or how much material is being removed from the part? Let’s take a look at some of the factors affecting the ‘Diameter Mode Dilemma’...
    Scale resolution
    Scale resolution affects the displays ability to measure cross slide movement. The current “industry standard” scale is the 5 micron (5μm) scale. The smallest movement a 5 micron scale can detect is .0002”. Therefore, a 5 micron scale “counts” in two ten-thousandths increments, ie when you move your machine it will count .0002”, .0004”, .0006” etc. But remember, the cross slide removes twice the amount of material than the cross slide moves. So while your cross slide is moving .0002”, .0004”, .0006” you’re really removing .0004”, .0008”, and .0012” of material from your part.
    What it boils down to, is the smallest measurable increment you can reduce your part is .0004”, which would be the resultant travel when a cross slide scale moves .0002”.
    Sent from my iPhone using Tapatalk
    Last edited by Tungsten dipper; 01-11-2019 at 07:58 AM.

  8. #8
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    Tungsten
    Thanks that helps alot.

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