Page 1 of 3 123 LastLast
Results 1 to 15 of 35
  1. #1
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default Ebay "Precision Granite Square"

    Hi all,

    Been looking for a precision square on and off for a while now. I have a nice Moore & Wright Grade B but would like either a grade 0 or 00 for more accurate work. Also the M & W has a thin bevelled edge and so is very difficult to indicate off.

    It won't be used all that often so I can't really justify mega bucks for it, hence why I still don't own one! I have noticed for some time that there are plenty of granite squares on ebay purporting to be grade 00 for very cheap (too cheap I suspect) so for around the $125 mark delivered I bought one of these:

    https://www.ebay.com.au/itm/Cake-Pan...EAAOSwZrtcZUst

    There are a number of these offered on eBay (all with the same model number HHIP-4901-2705) varying in price from what I paid all the way to around $400 in the UK.

    A question for the brains trust out there, is there any way of testing it's squareness without the use of another master square? I have tested my M&W but its easier to do because the blade is parallel, you can test it by using a method similar to this.

    https://www.youtube.com/watch?v=Qrxvs0b_ecs

    Obviously that method is of little use with a triangle type square like a granite square.


    Cheers,

    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.

  2. #2
    Join Date
    Jul 2016
    Location
    Melbourne
    Age
    35
    Posts
    1,522

    Default

    I cannot answer your actual question. I do have a mahr 00 grade square to try it against. I can lend it to you and I'm not far away.

  3. #3
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Quote Originally Posted by simonl View Post
    A question for the brains trust out there, is there any way of testing it's squareness without the use of another master square? I have tested my M&W but its easier to do because the blade is parallel, you can test it by using a method similar to this.

    Obviously that method is of little use with a triangle type square like a granite square.
    Simon
    Would it be possible to check against a cylinderical square. Set it up on your Granite Surface Plate, and slide a feeler gauge between the 2 at the top and the bottom, you should be able to feel the same amount of drag if it's right.
    I believe gudgeon pins make good Cylinererical Gauges. For those that don't know, a Gudgeon Pin is what connects the piston to the conrod in an engine. If you went to an engine reconditioner, they'd probably give them to you, heavy truck ones are longer, as they have bigger pistons.
    HTH
    Kryn
    To grow old is mandatory, growing up is optional.

  4. #4
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Thanks Cask,

    might be a good excuse for an afternoon get-together in the shed.

    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.

  5. #5
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Thanks for the idea Kryn. Thing is, I still don't know how square the gudgeon pin is. I would rather come away with an actual figure rather than an idea.

    Ultimately I would like to use this square as the reference square in my shed but if I really got no idea then it's a bit meaningless.

    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.

  6. #6
    Join Date
    Apr 2018
    Location
    Drouin Vic
    Posts
    633

    Default

    Here's a suggestion that seems to work in my head; take a straight edge and a parallel and set the parallel square to, and half-way along, the straight edge using your granite square, then move the square around to the other side of the parallel, set it say an inch away and measure the gap at top and bottom with an internal mic, bore gauge or similar. Could be done vertically with a cylindrical gauge on a surface plate, or horizontally if you can clamp the straight edge and parallel in position, say on your mill.

  7. #7
    Join Date
    Aug 2008
    Location
    Melbourne
    Age
    34
    Posts
    1,075

    Default

    If your surface plate is perfectly level, you could sit one of these against the vertical edge of the square and see what adjustment is needed to level the vial https://www.ebay.com.au/itm/MACHINIS...1/153451732884

  8. #8
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Quote Originally Posted by Pete O View Post
    Here's a suggestion that seems to work in my head; take a straight edge and a parallel and set the parallel square to, and half-way along, the straight edge using your granite square, then move the square around to the other side of the parallel, set it say an inch away and measure the gap at top and bottom with an internal mic, bore gauge or similar. Could be done vertically with a cylindrical gauge on a surface plate, or horizontally if you can clamp the straight edge and parallel in position, say on your mill.
    Yep, that should work in theory. I may be a bit clumbsy to make it work in a practical sense but worth a try. The difference between the upper and lower is twice the error of the square from top to bottom.

    Hi Elan,

    Only issue with that idea is is that it is now relying on the squareness of that item you linked to in eBay. I would be back to square one. No pun intended!

    Edit: I think I misunderstood how that plumb gauge works. I'm still not sure but I'm intrigued. You may have something there but I'll have to think about it.

    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.

  9. #9
    Join Date
    Aug 2008
    Location
    near Rockhampton
    Posts
    6,216

    Default

    An autocollimator and a pentaprism will do it very accurately. Bring it over one weekend.
    Gold, the colour of choice for the discerning person.

  10. #10
    Join Date
    Mar 2014
    Location
    South of Adelaide
    Posts
    1,225

    Default

    Do you know the technique to check the squareness of a block with a surface gauge and indicator? If the sides of the square are fairly flat and parallel you could use them to calibrate the indicator and then check the working surface.
    I also have a square on the way now.

  11. #11
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Thanks RC. I'd love to come visit one day!

    Simon


    Sent from my SM-G970F using Tapatalk
    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.

  12. #12
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Hey snap,

    What sort of square did you purchase?

    Simon

    Sent from my SM-G970F using Tapatalk
    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.

  13. #13
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    Simon I think you don't have the equipment to test for squareness accurately, if the granite square had perfectly square corners then you might get a close idea by accurately measuring and then using pythagorus theorem.

    If you use 2 granite squares on a plate and push them together with a strong light behind them you should see no light emanating from the other side.

    If no light is apparent between them and if the hypotenuse of the same brand and model of squares is lapped then to measure them you could sit them one on top of the other, hypotenuse to hypotenuse to make a rectangle, sit them on a plate and run a dti along the top long side and then stand them up and run the DTI along the short side that is now at the top, then you could average the 2 figures, that is if you got any variation on the DTI

  14. #14
    Join Date
    Mar 2008
    Location
    nowra
    Posts
    1,598

    Default

    I bought a square from another Source. With The surface plate Group buy recently. It was slightly more expensive but not much more it's also a grade 00
    BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

    Andre

  15. #15
    Join Date
    Aug 2012
    Location
    Australia
    Posts
    645

    Default

    I used my PMC Lonestar SquareMaster to check mine. If I recall, my square was well within the stated accuracy.

Page 1 of 3 123 LastLast

Similar Threads

  1. Ignyte Precision Granite Surface Plate 24" x 18" x 4"
    By kwijibo99 in forum METALWORK - Machinery, Equipment, MARKET
    Replies: 10
    Last Post: 5th Jul 2016, 10:41 PM
  2. An "unearthed" CVA precision capstan lathe
    By jhovel in forum METALWORK GENERAL
    Replies: 14
    Last Post: 2nd Jul 2011, 12:16 PM
  3. hercus 9" precision lathe
    By Metal Tinkera in forum THE HERCUS AREA
    Replies: 9
    Last Post: 19th Apr 2011, 07:55 PM
  4. Replies: 6
    Last Post: 5th May 2009, 08:18 PM
  5. Difference "Galvanised" and "Primed" Steel
    By Fr_303 in forum METALWORK GENERAL
    Replies: 4
    Last Post: 22nd Jan 2008, 05:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •