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    Actual results. I picked up the four thin slices, and the larger center piece.

    All in all, the work looked to be great. Cuts were clean and very smooth. Edges sharp with just a little breakout, as expected. Will clean up the cut edges with a diamond stone.

    This is a first quick report, nothing too extensive yet.

    Not having a qualified surface plate to work off of (and keep in mind this plate was rather abused in it's life, and was not qualified either), I did the next best thing for what I had, and ran an indicator along one slice, reading the other slice. So basically compared the two surfaces for relative differences.

    After a fair amount of shimming and fiddling, running a 0.0001 indicator along them showed a deviation of less than 0.0001" (yes, the indicator moved under a tenth (and I put a piece of tape on the surface being read to make sure it was working) as I went form one end to the other.


    No comments on the art work.
    Attached Thumbnails Attached Thumbnails img_1161.jpg  

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    More photos

    img_1156.jpgimg_1157.jpgimg_1158.jpgimg_1159.jpgimg_1160.jpg

    These were a random two slices, I don't know where they came from relative to each other. I will try to follow the grain and scratches later to try to figure it out.

    All in all, if they did 'banana' when cut, they did so in the exact same manner.

    Photos taken about equally spaced along the length.

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    Quote Originally Posted by mfisher View Post
    Actual results. I picked up the four thin slices, and the larger center piece.

    All in all, the work looked to be great. Cuts were clean and very smooth. Edges sharp with just a little breakout, as expected. Will clean up the cut edges with a diamond stone.

    This is a first quick report, nothing too extensive yet.

    Not having a qualified surface plate to work off of (and keep in mind this plate was rather abused in it's life, and was not qualified either), I did the next best thing for what I had, and ran an indicator along one slice, reading the other slice. So basically compared the two surfaces for relative differences.

    After a fair amount of shimming and fiddling, running a 0.0001 indicator along them showed a deviation of less than 0.0001" (yes, the indicator moved under a tenth (and I put a piece of tape on the surface being read to make sure it was working) as I went form one end to the other.


    No comments on the art work.
    Interesting stuff and at first glance looking good

    Careful not to read to much into readings with things setup as you have. The surfaces can move independently of each other when not mounted solidly, plenty potential for .

    Could setup them up one atop the other and indicate between the two surfaces. Plates can wear all which ways but if you take neighbouring slices youll read twice the error if the surfaces have a similar profile.
    Can set the blocks/parallels at the ends and at the airy points and compare readings, can load the top beam to see if you can measure any deflection etc. No limits

    I love learning

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    Or a simpler way would be to put the bottom one on the Airy points or at 30% and use 3 or 5 or the same thickness feeler gages spread along surface and set one on top of the other and try to pull out the shims. Then if they are all pretty uniform great. Stick a piece of masking tape on the side of the parts to mark your results, then flip the top parallel over and 180 degree's and test it again and see if the tightness readings are the same. So far what's your total investment in money and how much time? I understand the first ones will cost more. You could also try the 3 plate method with bluing but that could get messy. This is a great thread, Thanks. Rich

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    One complicating factor is that I am pretty sure the donor plate was not flat. Judging by the scratches, dings, chips, and that it was living in mud, I don't expect much in an absolute flatness, more looking for relative movement from cutting.

    When I took the 18x24 plate and tried placing it face to face with the 24x36 plate, all I got touching was the four very corners of the smaller plate. I will take some of these suggestions and see what more I can tell.

    There is a chance I might be able to stop by Texas 3, if you are willing to allow a visitor for an hour or two. If so, I will bring a slice or two. Let the pros inspect them.

    Also, is it possible for granite to absorb grease/oil? I would think not, but I swear that the rollback truck dripped all sorts of things on the plates, that seems to have permeated the stone. Maybe it is just coloring of the stone, but it will not come off windex or alcohol yet. Will try other solvents.

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    As to the three plate method - was thinking of using that to bring the four slices into flat.

    As to costs - excluding the plates themselves (which were cheap due to condition), I has to cut the four sides of the plate (to clear off the 1/2" bevel on each side) before slicing, plus then four cuts for the slices. 8 cuts total. $20 a cut, so I am into it for $160 so far. If it wasn't for having to clear off the bevels, it would have been half that. For that I have the four 2" slices, plus a 13" center slab left.

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    Sure your invited to stop by...not on day 1 if possible. You know were pretty busy the first few days... Also, sure plates absorb...especially bluing on pink ones. I use acidtone and then windex. Steve has a big plate too.... Did you get a chance to take pictures of how they cut them?

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    Hand lapping is a solution to these problems using very fine abrasive and a small piece of granite the high areas can be lowered, before scraping surface plates were made
    by using various abrasive paper.

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    I just put the two finished faces, face to face and eyeballed the space then tried a shim to find about .0015 or about .0007 in 24" each.. way too much to be of any use.. guess I could put them on the 13 grinder and grind them to .0002 or so...Think likely stresses released made the warp/bend. They went convex or hollow center when face to face.

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    Default More results - still looks good

    Sorry for the delay, got caught up in other things, and had to eliminate a few gremlins.

    The update. I took two of the slices, and as Richard suggested I took 5 strips of 0.0015 Starrett shim stock between the two granite strips set face to face, and setting on blocks, supported at 30/40/30. From this the extreme ends were tight, and had maybe a 0.003 gap in the center. NOT GOOD. This didn't make too much sense since the indicator showed them to be very parallel.

    Figured it was worth a try to do the same test with the granite strips back to back. When set this way, all 5 strips had nearly the same pressure (keep in mind the backs were not precision, but good enough to try). Odd that the backs seemed to be flatter than the tops. So I pulled out a micrometer, and the ends of the granite slices were about 0.001 thicker than the center.

    OK, when I started this, I knew the surface plates were worn and damaged, but that was more than I expected.

    At this point, I made up a sawhorse and moved all four strips to my basement. The gremlins came out, which I finally figured to be an uninsulated hot water heating pipe that was close enough above them to start warming the strips from the top and making them bow. Moved the setup, and all was good.

    So now the top faces appeared to be very high on the very edges. But the edges had a different look/feel than the centers. So I cleaned, and cleaned and cleaned some more. Still different feel to it. Having nothing to loose, I took out some 600 grit wet/dry paper, and gave the edges a little polish. The paper glazed over instantly. Not with granite dust, but more like a varnish residue. Really odd. Acetone, paint remover, razor blade, nothing could take it off.

    Still nothing to loose, so out came the 320 grit wet/dry. After a short time I was able to clean up the ends of three of the strips, so that I was getting granite dust and not glazing over the sandpaper. Still don't know what was on the surface plate, but it had a bit of a varnish type smell to the dust.

    Did I mention that the surface plates had not been treated kindly in the past?

    So where did this get me?

    Working with three strips, supported at 30/40/30 roughly, labeled A, B and C from right to left.
    edge-names.jpgedge-names.jpg

    I will apologize, but trying to get good photos of bluing a dark surface plate, without getting it all 'smurfy' is not easy.

    Here is B and C printed off of slice A.
    c-.jpgb-.jpg

    Here is C and A printed off of slice B.
    b.jpgc-b.jpg

    more to follow.

  12. #51
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    Default and more results

    picking back up, here is B and A printed from slice C.
    c.jpgb-c.jpg

    I know A from C should be the same as C from A, but figured going both ways as it were could provide some more detail.

    Looking at a close up of one

    b-c-close-1.jpgb-c-close-2.jpgb-c-close-3.jpg
    three pictures along B printed from C.

    In general, there is fairly good contact along the whole length. In some of the photos, the other strip is a little dark from being cleaned with windex.

    If this was cast iron, I would say that the contact is not that great. But with granite that is smooth, and hopefully Richard will respond with some ideas, I had to go very light with the blue, or else the two surfaces would stick together, and basically be blued across the entire surface. There are no 'bearing points and oil reservoirs', no highs and lows from scraping, so contact should be a much higher percentage? But how to test for that with blue? Going very light is difficult to see, and may not give a proper picture, but going just a little heavier and all detail is lost.

    Time for an optical flat to judge absolute flatness?

    Still, for what I started with (remember, two surface plates that were sitting face down in mud/grease under a wrecker, about to be made into a wood splitting block), I would have to say that these three strips look like they could be made into something useful. And the cost to do it is still not that high (compared to having the surface plate recertfied). I still have the fourth strip to clean, plus the large section, about 14"x 35" that I will use as a surface plate one I get to it.

    I have not gotten any diamond dust or lapping compound to work the three straight edges against each other to really lap them in against each other.

    Thoughts / observations / comments / suggestions / criticism / random scraps of wisdom to cast?

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    Matt,
    What about using different spotting compounds? Canode yellow or orange could work well. Otherwise, you could experiment with red iron oxide (very cheap) or zinc white. Kremer Pigments is a fairly good source for this kind of things.
    If Saturday you have time to pass by Tuckahoe, I can provide you with a few samples of various stuff.
    Just send me an e-mail (you should still have the address from the scraping class).

    Paolo

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    I started to think who's on first when I was looking at the pictures. I can't really see a difference with the bluing accept a line on the edges. Not sure what I was seeing. This being an experiment I was thinking I wonder if you taped some parchment paper or buthers paper down on one, taping it on the ends and then rubbing another one on it and seeing what happens? See if it rubs off or marks up the same. I have never mic'ed parchment / buthers paper so no clue if it would make a difference. Maybe you can call a local machine shop and ask if you can check them on a plate or bite the bullet and take them to the plate lapper you mentioned before.

    When you indicated the plates sitting side by side and got .0001 I am assuming the were worn parallel. Did you move the bottom support shims to say 25/50/25 and did that change the tightness of the 5 shims?

    It would be interesting if you had a laser Infrared Thermometer and tested the temp on top and bottom when it warped under the pipe. Or how about placing a 100 watt light bulb under one for 10 min...20 min..etc.
    just for the fun to see what happens. Rich

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    I tried red, and it came up even harder to read. Using red on the one surface to be printed, and then printing blue was even worse.

    The line on the edge is often just the 'uninvolved' strip still damp from cleaning. Yes, very hard to see the blue. If you zoom in it can be seen, if you have a good monitor.

    I will try parchment paper, see what that does. Or maybe get a roll of cash register paper (the thin stuff). Instead of putting in in between, I would take a strip, and use one strip that has been printed as a stamp. So if I blue A, print B off of A, then take B and transfer the blue from B to the paper?

    Can try putting a light on and see how much it moves, but for the heat pipe, it goes from contact across the surface to just contact in the center, with a tiny bit of rocking if the heat was running for a while. I am happy to be away from that gremlin, and don't think I will go back unless we get snowed in for a week and run out of other projects.

    I forgot to include in the previous - one of the delays I had was that I was going to make up a trough out of metal, and set one of the granite strips in there. See if I can get the wrecker grease to leach out into acetone or some solvent. I am amazed that there is a grease stain almost through from the bottom of the plate where the grease/oil/fluids dripped.

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    Matt,
    I'd believe that the yellow Canode would give you enough contrast even in thin layer. Anyhow, one advantage of iron oxides (both red and yellow) is that you can mix them with some volatile solvent and deposit by evaporation, like the old text books describe one of the uses of red lead. This would give you a very delicate and very visible layer.
    As I mentioned earlier, if Saturday you can pass by the Machine Shop Museum, I could bring you a little bit of yellow and some iron oxides for you to try out.

    I like the idea of the paper, but I'm afraid that it won't work as "in-between medium". What about spotting as you did so far, then transfer the ink to paper with a strip of transparent Scotch tape, like you can see done in a few of the videos taken at the Georgia class?

    Paolo

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    Paolo - thanks for the offer, but Saturdays are generally real busy for me, but might need to take you up on that. By the way, did you find a pair of 12" Dewalt clamps and an orange three outlet extension cord after the class? If they are there, consider them donated. I just want to know where they are, so I don't have to keep thinking about where I left them.

    I think first attempt will be to use the spotted piece as a stamp onto a strip of white paper. See if that works. If not, using a clear packing tape to pull off the blue, and then set that on the paper should work. Should be able to try both of those tonight. If either work, that should be much more visible then the blue on black I have now.

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    some work last night:

    first - nothing sticks to the parchment paper I have. That is great for making fruitcakes (and don't disparage fruitcake until you have some good home made cake), but using for blue transfer not so great.

    second - the receipt paper I have, which is about 2.3" wide, is too thick, and too irregular to use in between the two pieces of granite, to take the blue directly from the one being used as a master.

    sandwiched.jpg

    too much contact from the paper squishing during the transfer.

    Which brings to to using packing tape, that is just at 2" wide, to pull the blue from the printed granite slice, and then stuck to the register tape to see the blue.

    First, a blank, to make sure that there is no leftover blue on the granite strips.

    blank.jpg

    I did drop the tape, and picked up a little floor dust on the tape after sticking to the granite, thus the large specs on the tape.

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    So now the real results.

    Using granite slice A as the master, and bluing it somewhat heavily as was needed to show up on the other granite strip, and then printing B from A. Then take the tape, pull the blue off of B, and stick it to a strip of paper.

    heavy-blue.jpg

    Success! Blue is a little heavy, but not really smurfed. Since it looked like I could go lighter on the blue to show more accurate contact points, I cleaned off A, and reblued a bit lighter. The tape is blued, and then there is a strip of the plain white paper along the side, since the paper is wider than the tape.

    This time I printed both B and C from A. Took a strip of tape to each one, pulled the blue off and taped to strips of paper.

    The ends of the strip:
    ends.jpg

    Close up in the middle:
    closeup.jpg

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    And now three photos of the two prints, along the length from one end to the other.

    img_1623.jpgimg_1624.jpgimg_1625.jpg

    The blue is light, since I wanted to show as much distinction between contact and not.

    This really looks like there is excellent contact along the entire length.

    This is for B and C printed from A. I need to print the other combinations as well, but from the previous hard to view the direct results test, I believe that they will be very similar.

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    Quote Originally Posted by mfisher View Post
    And now three photos of the two prints, along the length from one end to the other.

    img_1623.jpgimg_1624.jpgimg_1625.jpg

    The blue is light, since I wanted to show as much distinction between contact and not.

    This really looks like there is excellent contact along the entire length.

    This is for B and C printed from A. I need to print the other combinations as well, but from the previous hard to view the direct results test, I believe that they will be very similar.
    Matt,

    get a can of this

    Krylon(R) Easy-Tack™ Repositionable Adhesive

    Use regular paper and do the "scraping" in reverse . I.E take off material from the non paper covered SE where it touches the paper covered one.

    dee
    ;-D


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