Best way to add a DRO to a Jones and Shipman 540 APR? - Page 2
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  1. #21
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    Quote Originally Posted by adama View Post
    As to dressing, you want a wheel head dresser.
    Got one -- look at the thing on top of the wheel guard in the photo in my very first post in this thread. The black ball handle to the right slides the dresser forwards and back, and the micrometer screw on top lowers the diamond. Yes, very useful!

    How would it like the oil and dust though? Its nothing like a clean environment directly under the table on a J&S 540? Don't have - never been around a cylindrical so don't know how well it compares?
    That's a good point. Under the cylindrical grinder there are hydraulics, but none of it is leaking or feeding oil "out in the open". I'll need to look closely under the J&S 540 to see if there is a similar "dry zone".

    [EDIT] I had a look in my photo collection and found these. Indeed it is "wetter" than under the Studer table. But not hopeless.



    One possible location is under the table halfway in between the hydraulic cylinder and the V-way. It looks clear in that area:



    From the photos it seems there is plenty of clearance (I only need 2 or 3mm). But I'll have to pull the table and take measurements. I'll probably only do that after the other two axes are finished, since they are the most important ones.
    Last edited by ballen; 05-04-2019 at 04:13 PM.

  2. #22
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    Yes, same dresser as mine, did not see that pic, my bad.

    looking at mine, from the end, yeah would probably squeeze in above the table ram, got a machined land there too like yours has, hopefully parallel to the ways, drop the reader head in between the 2 oil pipes off the ram, using the 2 bolts on thoes there and just make a bridge like arrangement, you got the flat way to work out all your heights off, run the cable in the bottom of the rack grove out the non gear side? If you need a bit more clearance, you could counter bore the ram gland block bolts down a little more and reduce the bolt head heights - machine a easy 1/8" off the blocks on one side.

    Being on the top of the table it would remain oil free if your running coolant or extractor i don't think that much crap gets under the table, at least when i got mine and took the table off i was seriously surprised by just how clean it was under there! But then again it realy depends how sensitive those readers are to dust. But like that it would be scale down, so only the reader head for the dust to land on, minimizing that issue.

    If your using those same scales for the wheel head up - down, modifying the guards so you can use that flat face on the front of the coulomb would be ideal, that said, may be possible to even put it inside the coulomb, the whole verticle slide bit can lift out the top if you take the motor + spindle off, seam to remember on mine there is some reasonably flat lands in there you could use for such a small scale. Can't realy see and going off memory though as mines got a fair bit of stuff around it right now.

    So yeah, table could be pretty easy to do with those as scales, that's if you can think of a use for doing it though? Just because you can, well im not sold its going to be of much use, hell prove me wrong!

  3. #23
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    Quote Originally Posted by adama View Post
    Would probably squeeze in above the table ram, got a machined land there too like yours has, hopefully parallel to the ways, drop the reader head in between the 2 oil pipes off the ram, using the 2 bolts on those there and just make a bridge like arrangement, you got the flat way to work out all your heights off, run the cable in the bottom of the rack grove out the non gear side?
    I had been thinking of the space in between the V-way and the hydraulic cylinder. But you are right, there is space next to the gear rack, and that has a number of advantages. (a) It is closer to the centerline of the table (b) There is an obvious easy path to get the cabling out (c) As you say I could make a bridge between the two central bolts on the oil piping. I would probably not mount the head that way, out of concern that the hydraulic forces on the ram would be transferred via the pipes to the head and shift it back and forth. But I could use the two central bolts to mount a "bridge guide" with some drill bushings for drilling and tapping mounting holes in the base between those two bolts. Then I could bolt down a small head mounting block in that area.

    Being on the top of the table it would remain oil free if your running coolant or extractor i don't think that much crap gets under the table, at least when i got mine and took the table off i was seriously surprised by just how clean it was under there! But then again it realy depends how sensitive those readers are to dust. But like that it would be scale down, so only the reader head for the dust to land on, minimizing that issue.
    That right. Just look at the photo of the table upside down. It's clean and dry there: a perfect location for a scale.

    If your using those same scales for the wheel head up - down <SNIP> may be possible to even put it inside the column, the whole vertical slide bit can lift out the top if you take the motor + spindle off, seem to remember on mine there is some reasonably flat lands in there you could use for such a small scale.
    I've got to look more closely, but I really like the idea of getting the scale inside the column halfway in between the two vertical rails. That's the location that minimises the errors from any rocking, and the scale would be very well protected there.

    So yeah, table could be pretty easy to do with those as scales, that's if you can think of a use for doing it though? Just because you can, well I'm not sold its going to be of much use, hell prove me wrong!
    You might be right, I am still thinking this through. One thing I might use it for is for setting a part on the table at a particular horizontal or vertical angle. I calculate the tangent of the angle, put an indicator on the edge and zero, then make sure that after I shift the two horizontal axes or the horizontal and vertical axes by the correct amounts, that the indicator reads zero again. I use this method on my mill and lathe from time to time. Not as precise as a sine table and gage blocks but not bad.

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    Yeah, sure thoes are hydrulic lines, but once again, the J&S540 runs its hydraulics at what 120 psi? Thats not going to flex thoes bolts a micron is it? Equally with no fine movement on that slide and only the rack and pinion, just what do you realistically think your going to have control wise?

    I can assure you the table reversal is not repetitive to even single digit mm, so best advice is don't get too carried away, you want it usable.

    As to drilling your own holes, might want to look at whats bellow there, would suck to drill into something important, never had the saddle per say off mine so never really worked out if the valve blocks are part off or separate to said saddle casting.

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    It's been a while since I last posted about this, but I finally got the vertical axis scale installed. Some details (photos) are here in the Metrology forum:

    Best practice: vertical axis DRO scale on a surface grinder

    The resolution of the DRO is 0.1 microns, or 4 millions of an inch. It's remarkably stable, even with the machine running the last digit doesn't flicker (though it does slowly shift as the machine warms or cools).

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    Install of cross and vertical DRO axes is finished:



    I made the X be cross and Y be vertical, figuring that this was more consistent with my lathe. Is there a convention for this on DROs? Since the vertical axis is most important, perhaps I should make that be X.

    I'm also going to add an encoder to the long axis, so will eventually swap this DRO for the three-axis one currently on my cylindrical grinder, which only uses 2 DRO axes.

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    The correct designation for axes on a surface grinder is longitudinal (table back and forth) = X, head/spindle up and down = Y, cross feed = Z. Lots of people seem to call the head up and down = Z.

    When you are looking into the end of the spindle, X should be the axis that's moving side to side, Z is toward or away from the spindle, Y is spindle C/L up and down or toward/away from operator depending on orientation (latter for vertical spindle).

  10. #28
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    Ok, I got Y right. Will have to swap X and Z once third axis encoder is installed.


    Sent from my iPhone using Tapatalk

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    Adding a DRO to the surface grinder was a good move. I find myself using the grinder more than before, because it's now quicker.

    An example: I needed to shorten four small cylindrical spacers by about 1.5mm. Previously I would have done that on the lathe in a few minutes, one at a time, with a stop. It's now quicker to put them together on the surface grinder, do a few passes, take one off to measure, set DRO, then come down to the correct size. I did this dry, no coolant, no clean up time.

    If I was doing this without the DRO, it would be somewhere between 7 and 8 hand wheel revolutions to come down that far. I hadn't appreciated how much time it took to keep track of that -- it kept me from going to the grinder for such simple things.

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    I'm with you. Currently I only have a readout on the head of my grinder, but have two more scales and a readout waiting for install. I see a lot of comments regarding readouts being not that useful on a grinder, but these are likely from guys doing mostly flat surface grinding. If the grinder is used for other purposes like cup wheel grinding or small toolmaking projects, having readouts on all 3 axes is very useful indeed IMO. I also have plans to add them on my Monoset.
    Last edited by eKretz; 11-16-2021 at 12:27 PM.

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  14. #31
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    Another point I have realized, why the DRO speeds things up a lot.

    My J&S 540 APR has a power up/down feed. (It's important because the vertical screw is 0.2mm per handwheel revolution. Without power feed, moving up 100mm (4 inches) means 500 turns of the handwheel!) But when I use the power up/down feed, I lose the zero on the handwheel. The DRO doesn't care about that -- I always know where the grinding wheel is, for any combination of power and hand feed.

    So if I want to use a chuck-mounted diamond and need to come significantly up or down for that, it's now a lot quicker.

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