What is it?

I've been collecting unusual objects for quite a while, and several years ago I started posting them on this site as puzzles for visitors to figure out what they are. Most of the items are mine but a few belong to others, if you aren't interested in tools there are plenty of other type objects that have also been posted.

For first time visitors I recommend this archive for a wide variety of some of my best pieces.

Wednesday, March 30, 2005

308. 7/8" diameter






309. 3 3/4" long, 3 pounds 6 ounces







310.




311. 3 5/8" tall






312. The puzzle for this one is to determine how the top piece of this stacked freestanding wood is able to entirely overhang the bottom piece.



313. 3 1/4" long



314. 3 1/2" tall






Answers

16 Comments:

  • 308 - a set of stair gages that clamp to a framing square for laying out stair carriers.

    By Anonymous Anonymous, at 3/30/2005 6:36 PM  

  • 310- A pencil sharpener

    By Anonymous Anonymous, at 3/30/2005 6:37 PM  

  • 309. A dolly, used in body shops to back a hammer blow when removing small dents.

    By Blogger pa-ter, at 3/30/2005 9:27 PM  

  • 312 - The center of gravity (on the horizontal axis) is still located less than halfway to the left of the bottom-most object;

    By Anonymous Anonymous, at 3/30/2005 10:04 PM  

  • 308. Square stops for a framing square

    309. Metal dolly used to back a hammer for auto bodywork

    310. Pencil sharpener

    311. Grommet punch

    312. The center of mass is still centered

    313. Curta rotary Calculator

    By Anonymous Robert Roach, at 3/30/2005 10:15 PM  

  • >308 - a set of stair gages...

    >310- A pencil sharpener

    >309. A dolly, used in body shops...

    These are all correct.

    >312 - The center of gravity (on the horizontal axis) is still located less than halfway to the left of the bottom-most object;

    There is more overhang in this stack of wood than you could normally get, though with nothing to compare it to I guess it's hard to tell. I'd like to change the question here to: What design feature was used to maximize the horizontal overhang?

    >308. Square stops for a framing square

    >309. Metal dolly used to back a hammer for auto bodywork

    >310. Pencil sharpener

    >311. Grommet punch

    >312. The center of mass is still centered

    >313. Curta rotary Calculator

    All correct.


    Rob

    By Blogger Rob, at 3/31/2005 8:08 PM  

  • 312: This overhang is based on the fact that the harmonic series,

    1 + 1/2 + 1/3 + 1/4 + ...

    diverges. The top is halfway over the second, which is 1/3 of the way over the third, which is 1/4 of the way over the fourth, etc.

    In principle, one could have an overhang as large as one wants, though one would have to have an awful lot of planks.

    Dave

    By Anonymous Anonymous, at 4/01/2005 8:01 PM  

  • Actually, looking at it more closely, we see that the top is halfway over the second, which is 1/4 of the way over the third, which is 1/6 of the way over the fourth, etc...

    The sum

    1/2 + 1/4 + 1/6 + 1/8 + ...

    also diverges, so we can still get as large an overhang as we would like. I think (though I don't want to go through the math) that as long as the planks are placed as described above, the center of gravity of the mass will be right at the halfway point of the bottom plank, implying that the structure will not tip over.

    Dave

    By Anonymous Anonymous, at 4/01/2005 8:03 PM  

  • Actually, looking at it more closely, we see that the top is halfway over the second, which is 1/4 of the way over the third, which is 1/6 of the way over the fourth, etc...

    The sum

    1/2 + 1/4 + 1/6 + 1/8 + ...

    also diverges, so we can still get as large an overhang as we would like. I think (though I don't want to go through the math) that as long as the planks are placed as described above, the center of gravity of the mass will be right at the halfway point of the bottom plank, implying that the structure will not tip over.

    Dave

    By Anonymous Anonymous, at 4/01/2005 8:03 PM  

  • In theory you could get as large of an overhang as you like, but in real life it doesn't seem like anyone could get the top piece offset by more than two or three lengths.
    According to "Omni Games", "for three lengths you would need 227
    pieces", and that's probably calculated using the exact fractions.
    When actually stacking them, it works better to pull the pieces back
    about an 1/8 of an inch, otherwise the structure becomes unstable very
    easily. According to the same book, for a ten length offset you would
    need 1.5 x 10^44 pieces!

    As I mentioned earlier, this structure was designed to maximize the horizontal overhang.

    Rob

    By Blogger Rob, at 4/02/2005 5:42 PM  

  • 312. Water on the flat surfaces will do it.
    313. A saw
    314 is the calculator

    By Blogger Canem, at 4/02/2005 8:14 PM  

  • >312. Water on the flat surfaces >will do it.

    Water wasn't used on this one.

    >313. A saw

    This tool is not used for cutting.

    >314 is the calculator

    Correct.

    By Blogger Rob, at 4/02/2005 8:49 PM  

  • 312. What if the last (top) piece is pear or triangular in shape with the larger mass being on the stack & the overhang being the smaller end, giving it a weight advantage.

    By Blogger pa-ter, at 4/04/2005 4:43 PM  

  • >312. What if the last (top) piece is pear or triangular in shape...

    Correct, at least you have the right idea, they aren't quite triangles but they are wider at the back, and all of the pieces are the same shape.

    Rob

    By Blogger Rob, at 4/04/2005 4:57 PM  

  • 308: Square stops for repeated marking of rafter cuts/stair stringers and such.
    309: Heel Dolly that someone used to test a number 8 stamping punch on.
    310: Depending on size either a pencil sharpener or a taper cutter for wooden spoke tenions.
    311: Punch for metal tabbed grommets.
    312: Tapered blocks?
    313: Scraper?
    314 : Curta type II mechanical calculating machine. Made in Liechtenstein (I have one just like it sitting on the desk)Don't leave it out in the open very long, they are worth BIG money. The type II runs about 900.00 - 1200.00

    By Anonymous Anonymous, at 4/05/2005 12:20 PM  

  • >308: Square stops...
    >309: Heel Dolly...

    Correct

    >310: Depending on size either a pencil sharpener...

    Pencil sharpener is right

    >311: Punch for metal tabbed grommets...
    >312: Tapered blocks?

    Correct

    >313: Scraper?

    I guess it could be classified as a scraper, see the answer link for details.

    >314 : Curta type II mechanical calculating machine...

    Yes

    By Blogger Rob, at 4/05/2005 2:47 PM  

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