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  1. #1
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    Default Large Engineering Squares

    I have some small engineering squares under 4" which are old Moore & Wright, etc but I was wanting a large one in the 12"/300mm or larger range and was wondering what experiances you guys have had with ones off ebay. Most of them are either unbranded or have an unknown name and I would guess all are Asian origin.


    For general purpose shop use (Marking Out, Machine Setup etc)are the one piece flat better than the traditional design, or the others? I know the flat ones wont stand on their own as readily.

    Accuracy??

    http://www.ebay.com.au/itm/KS-Tools-...item35ebe84cd6

    http://www.ebay.com.au/itm/Professio...item3f37a30650

    http://www.ebay.com.au/itm/245025-Si...item257933bc16

    http://www.ebay.com.au/itm/KS-Tools-...item4880302ca8

    I probably be just as happy or happier with a well cared for old one in the same price range if I could find one.
    …..Live a Quiet Life & Work with your Hands

  2. #2
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    Default

    Whatever you buy, I would make sure it meets DIN 875 standard. There aee several grades of accuracy in this DIN standard. For basic marking out, the lowest accuracy grade should suffice.

    I couldnt see a DIN 875 mentioned in any of those.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  3. #3
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    DIN 875/1 is the lowest grade.

    Do an ebay search. There are a few and not too pricey.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  4. #4
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    Default

    For anyone else who didn't know.

    http://www.limit.se/FineToolsAPI/Dow...24f8f62fb373d1


    symbol: µm or micrometer/micrometre = 0.001 mm Also known as a micron or Stinky Finger


    A human hair is about 90 µm in diameter. So it this level we are definitely splitting hairs
    …..Live a Quiet Life & Work with your Hands

  5. #5
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    Default

    The 400 X 600 ones are usually sold as framing squares. I had a Stanley, for 10 years, till some idjut put it through a guillotine, that was perfectly square. Have seen where machined blocks had a cut in them, the thickness of the square, and grub screws fitted to hold the square upright or against an edge. If it's not perfectly square,careful peening of the inner corner will move the long edge out, and the outer corner, will move it in, something I read after I spent $$ getting it machined.
    That was all I ever used for marking out of items on flat sheet or tacking a large frame up.
    Kryn

  6. #6
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    Default

    Quote Originally Posted by DSEL74 View Post
    For anyone else who didn't know.

    http://www.limit.se/FineToolsAPI/Dow...24f8f62fb373d1


    symbol: µm or micrometer/micrometre = 0.001 mm Also known as a micron or Stinky Finger


    A human hair is about 90 µm in diameter. So it this level we are definitely splitting hairs

    Depends what you use it for. The errors are cumulative. A 300mm long square to DIN 875/2 is allowed to have a straightness error of 20um plus an angle error of 50um. That is an allowed total error of 70um or 0.07mm, or nearly 1/10 of a millimeter. For general worksop use, DIN 675/1 would be the standard choice and would have a total permissible error of 35um or 0.035mm. For those eBay sqares that do not even mention accuracy (let alone compliance to DIN 875) all bets are off - I would not recommend them to tram a milling column.

    The real thing does not need to be overly expensive:
    http://www.ebay.com.au/itm/Anschlagw...item4ae959bf18

  7. #7
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    Bear in mind if you decide to "improve" tge accuracy of a square by machining/grinding the sides, then the sides will no longer be parallel. Fixing one part creates an issue elsewhere.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  8. #8
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    Quote Originally Posted by simonl View Post
    Bear in mind if you decide to "improve" tge accuracy of a square by machining/grinding the sides, then the sides will no longer be parallel. Fixing one part creates an issue elsewhere.

    Simon

    My experience on the cheap ones is they are not parallel to begin with..
    Gold, the colour of choice for the discerning person.

  9. #9
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    I guess I should have said if you grind both sides they will be parallel but thats an awful lot of trouble.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

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