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  1. #61
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    Well scientists have recently proven that, for the first time in history, the human brain is physically shrinking. In other words the human race is getting dumber. Judging by the crap they serve up on TV, while the gullible believe almost any bullshit published on the internet, I don't find that at all difficult to believe!

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  3. #62
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    100 PPI is another BS statement. Some self taught wind bag in my opinion. The best I have ever seen was 65 PPI on straight-edges done in Taiwan and a few students over the years. The picture below is 60 PPI scraped by my assistant Ted in Taiwan on Turcite using a pull scraper. Now try to imagine 100 points. Impossible and that guy has no clue. I have scraped Moore Jig Borers and have blued up columns where the ways were not worn and 40 PPI was their standard. I have worked on Sips, Dixies several Swiss made screw machines and 40 to 50 PPI was the standard. Anyone spouting 100 PPI has no clue. I have also used ground stones and found them to dull so fast. I use a Medium grit Indian stone and when you learn how to use them it works well. I have watched Sip trained Techs and they used a BIAX power scraper with a 20 radius blade and a 1/16 stroke and they stopped at 40 to 50 PPI then pulled out the pull scraper and gave it 2 finish scrapes to give it their signature scrape. Someone can tell you they can scrape 100 PPI but that's BS in my expert opinion! Rich
    Attached Thumbnails Attached Thumbnails dsc00534.jpg   dsc00541.jpg  

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  5. #63
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    Quote Originally Posted by Pete F View Post
    As far as surface plates, they do NOT have to be high in the middle ie convex, although that is ideal.
    Are you sure about that?

    Surface Plate Calibration and Conditioning - YouTube

  6. #64
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    Quote Originally Posted by Pete F View Post
    Well scientists have recently proven that, for the first time in history, the human brain is physically shrinking. In other words the human race is getting dumber. Judging by the crap they serve up on TV, while the gullible believe almost any bullshit published on the internet, I don't find that at all difficult to believe!
    Personally im glad youre back mate, been boring without you.
    Last edited by Demon73; 06-29-2016 at 08:55 AM. Reason: eeee mate

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    Quote Originally Posted by Demon73 View Post
    Yes I am sure about that. Just because someone says some shit on Youtube, does not make it part of any standard ... or even true See my comments above about what's causing the human brain to get smaller! Some seem to go out of their way to prove the theory! Incidentally, maybe it's about time you found another link to post when attempting to insult somebody, instead of that same crap one all the time.* I'm curious for an explanation as to why an unconstrained surface plate, of constant thickness, in stable environments (albeit of different temperatures) is going to magically change shape at the different temperatures (once they've obviously stabilised at that temperature), or do you honestly believe there's some voodoo magic in surface plates that make them defy the laws of physics.

    G'day Rich, yes I find 100 ppi "difficult to believe", to say the least. I'd never heard of anyone even claiming that before, nor why you'd want that extent. However I prefer to give a person the benefit of doubt until they prove themselves a BS artist. I politely asked him to demonstrate that in a video, and who knows maybe he will? I'm always hoping to learn, and if he can demonstrate that I'll be all over it and try to learn as much as I can from it. I do want to see that over the whole surface too, not just an area cherry picked out of a single 1x1" area!

    The picture of the piece scraped above is very nicely done, the guy's position while doing so ... ergh, not so much! I'd like to see him maintain that position for 8 hours, and then come back for the next week and repeat it I now generally use a "load balancer" (ie an octopus strap from the ceiling!!!) on the Biax these days. Roughing is fine, but I'm now too old and, well basically pathetic, to cradle a Biax for any length of time when picking out points to finish. I find taking most of the weight off helps maintain some semblance of posture so I'm not aching at the end of the day. I'd love to have a height adjustable work surface for scraping, it would be gold!

    What is the contrast that guy is using? I use plain old red oil paint from a craft store, rub it on the work with a mineral turpentine soaked rag, and then wipe almost all of it off. It leaves just enough to "stain" the work, as it seems to penetrate in to the pores of the CI. While it's effective, I think it may be slightly abrasive. Although most of it has been wiped off, there's no point in "lapping" my surface plate all the time, so I'm keeping an eye out for other options and there's no arguing about that photo! Edit: Actually now I look again it looks like he's using Canode Blue and Yellow right? I'm old school and still use grease based so if so, that's no good to me. Can't argue with his results however!!!

    * Edit: no don't bother. Welcome to my ignore list!

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    [QUOTE=Pete F;2790665]Yes I am sure about that. Just because someone says some shit on Youtube, does not make it part of any standard ... or even true ...QUOTE]

    Briefly:

    GGG-P-463 C PLATE SURFACE

    Click on "download." It's a standard. All answers are there.

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  10. #67
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    Thank you Forrest, I am well aware of that standard, and have it on my computer so don't need to download it. I was not asking any questions, therefore have no idea why you would quote me in providing that link. On the other hand if you can find in that standard anything that says surface plates change shape depending on the lunar phase or what season it is, please feel free to attach my name to bullshit!

    In the meanwhile, if anyone cared to actually bother reading that standard instead of idiotic posts to make themselves feel more important, they would find that it's actually quite straight forward and I merely echo what it says. I'm not actually that bright, however did learn to read as a child. So long as the surface plate has no significant temperature gradient through it, and it has been allowed to stabilise in the measuring/using environment, it couldn't give a toss what time of the year it is, and anyone who asserts otherwise is talking out their clacker! Indeed, unlike a lot of metrology, where an actual temperature in important to obtain a correct size, a surface plate merely needs to be flat, and of no specific size.

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    Quote Originally Posted by Pete F View Post
    Yes but that is part of the spec, so like I said, so long as it meets spec it is a good plate. A lot of plates will have their high and low points close to each other, especially at the tighter end of the spec range. It's not ideal, but many will wear like that in use anyway. The idea that plates are deliberately somehow manufactured to be high in the dead centre is just bullshit. That's likely what the manufacturer will be aiming for, but that's pretty much a perfect case outcome. A little like parts constantly falling in the centre of spec. regardless of everything else.

    Yes I'm sure there are a few people around who wouldn't cry a river is that had been my immediate destiny, but I'm happy to say I'm not dead yet! I just withdrew from all the negative crap on the forums and didn't read them for ages. I've been happily instead spending more time cycling and working on the house instead of reading how Tom's dick is bigger than Harry's .... according to Tom Sadly the colder temperatures have forced me inside more; twas 2.6 degrees here this morning. Brrrr!!!
    I never said they make them intentionally convex, they make them intentionally as flat as they can, and it is what it is within spec. If i had my choice i think i would like my plate to be convex within spec rather than concave within spec but it is not a buying option on any website. (no pull down with the choice ) If the plate is convex at least i know what to expect. The plate i have right now is all over the place more like a potato chip within spec Never asserted that a plate changes under any circumstances, the only thing i ever said is that on a plate that is not absolutely flat you only know what you make if it is not concave. All that of course within the limits of ones abilities and tooling.

    Then there was the definition what is flat convex and concave ... did i confuse anything?

    dee
    ;-D

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    Quote Originally Posted by dcsipo View Post
    I never said they make them intentionally convex, they make them intentionally as flat as they can, and it is what it is within spec. If i had my choice i think i would like my plate to be convex within spec rather than concave within spec but it is not a buying option on any website. (no pull down with the choice ) If the plate is convex at least i know what to expect. The plate i have right now is all over the place more like a potato chip within spec Never asserted that a plate changes under any circumstances, the only thing i ever said is that on a plate that is not absolutely flat you only know what you make if it is not concave. All that of course within the limits of ones abilities and tooling.

    Then there was the definition what is flat convex and concave ... did i confuse anything?

    dee
    ;-D
    Awesome, thank you for pointing out what you never said. By unremarkable coincidence I similarly didn't address any posts to you personally, so I guess we're now even!


    Quote Originally Posted by RC99 View Post
    Provided they do not blow out the repeat-o-meter test. There has to be a gradual slope between the highest and lowest point.
    RC I never said the earth was flat. Ooops sorry, I thought I'd get with the current fad of trying to make myself feel important by quoting somebody's name, and then going off on some obscure rant that has nothing to do with what they said

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  15. #70
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    Quote Originally Posted by Pete F View Post
    Thank you Forrest, I am well aware of that standard, and have it on my computer so don't need to download it. I was not asking any questions, therefore have no idea why you would quote me in providing that link. On the other hand if you can find in that standard anything that says surface plates change shape depending on the lunar phase or what season it is, please feel free to attach my name to bullshit!

    In the meanwhile, if anyone cared to actually bother reading that standard instead of idiotic posts to make themselves feel more important, they would find that it's actually quite straight forward and I merely echo what it says. I'm not actually that bright, however did learn to read as a child. So long as the surface plate has no significant temperature gradient through it, and it has been allowed to stabilise in the measuring/using environment, it couldn't give a toss what time of the year it is, and anyone who asserts otherwise is talking out their clacker! Indeed, unlike a lot of metrology, where an actual temperature in important to obtain a correct size, a surface plate merely needs to be flat, and of no specific size.
    Don't be so sensitive. I was agreeing with you and offering a link to the standard in support orf your remarks. That's why I said: "It's a standard. All answers are there." IOW, for the benefit of those wishing to distinguish stated requirements from BS.
    Last edited by Forrest Addy; 06-30-2016 at 06:06 AM.

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    Quote Originally Posted by Pete F View Post
    My 36" straight edge will spot correctly only in one point on the plate (the section along which I scraped it), otherwise the errors of the plate and the errors in the straight edge will add to the point it can be seen in the blue (and also how it behaves on the plate).
    You scraped your straight edge from this plate right? I'd suggest the issue is the plate is not being properly supported. Or that you need to get your plate lapped.

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    Quote Originally Posted by Pete F View Post
    Yes I am sure about that.
    Okidokie

    Quote Originally Posted by Pete F View Post
    Just because someone says some shit on Youtube, does not make it part of any standard ... or even true
    Yeeeah, but its not just an any old 'someone' though is it bruv.



    --------------------------------------

    Im just wondering if the meltdown comes before the lock? Im getting in early this time


  18. #73
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    Whew, gonna take some work to make that thing flat again. Umm, err, what's the spec for a card table for ordinary use, not necessarily lab grade?

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  20. #74
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    Four pages on scraping, concerning what wasn't even a scraping job?

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    Quote Originally Posted by TGTool View Post
    Whew, gonna take some work to make that thing flat again. Umm, err, what's the spec for a card table for ordinary use, not necessarily lab grade?
    No problem, it is just a bit concave now, easier to lap a concave surface anyway.


    dee
    ;-D

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    How old are you guys? Acting like a bunch of JR. High kids.

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    Quote Originally Posted by Richard King View Post
    How old are you guys? Acting like a bunch of JR. High kids.
    We must not be professionals.

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  26. #78
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    Well some of this is humorous, we seem to be going a bit astray from the original postings intent. I will close this for now. I am sure everyone has had a chance to voice an opinion and I dont see this thread making us any smarter or better so I am going to close it. Thanks to all who have participated, we do learn even from arguments and no hard feelings to anyone.

    Charles


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