13 October 2011

This is not an optical illusion

The nail passes through a hole in the two center "teeth" of the wooden block.  It's more-or-less in the center, parallel to the long axis of the block - not at a significant angle.

The nail is a normal carpentry item that has not been modified in any way (not cut and reassembled).

The wood is normal wood; the three notches were cut in a solid block of wood before the nail was inserted.  The wood has not been broken apart or glued together.

How was this done?  See if you can puzzle out the method before viewing the solution in the video below.  Credit to the Steve Ramsey at Woodworking for Mere Mortals, via within the crainium. YouTube link.

Addendum Oct 14:  Similar items here.  Hat tip to Duncan Creamer's via his comment at BoingBoing.


  1. Clever! Since the shadow of the nail isn't quite straight in the first picture, I thought it had been driven in diagonally from the back, so that it looked good from the front but would be obvious if you looked down from the top. This is better, though!

  2. what kind of wood would be best for this? A soft wood? Pine?

    Very cool! I want to make one!

  3. Mike, I wondered about that too. I found this after some searching:

    Some tips:
    Type of wood does mater, softwood (Pine, Redwood, etc.) is better than hardwoods (hickory, maple, white oak, etc.)
    Can be done with Red Oak, but scrap 2x4 Pine is so much cheaper.
    Wood with larger distance between growth rings is better than close dense wood growth rings.
    Wood should start off as kiln dried, less than 10% moisture. (Walls of the cells and all that...)
    Wood grain direction makes a difference (flat straight grain, and NO KNOTS.)

    The above tips found at this craft link -

    Vice with hardwood jaws will leave fewer scars to give away the solution.
    The end sections are normally twice the length of the middle sections. (I don't know why; IMHO, for looks only.)

  4. Here's another copy of the video (the one above was taken down)


  5. Fixed. Thanks, anon - it's better now to have the original video.

  6. I tried it this weekend with a piece of pine 2x4. Unfortunately, my wet wood ripped when under the vise. I think there was an issue with not getting a straight grip on the wood, and a bad piece of wood (growth rings).

    I'll try it again next weekend, when my family isn't around to see me boiling wood and wonder what's up.

    As far as the end sections being twice the width of the centers, well a lot of that has to do with the length of the nail. A standard nail needs to have narrow sections to go through in order to be able to see the space around. You cannot make the end sections that narrow, as they would easily crack when clamped (or even later, while being examined roughly)

  7. Mike, if you're successful, post a pic online, and I'll link to it.

  8. Dude, the song that was chosen...
    "policemen are my friend"
    "the government is never wrong"
    I hope that that was satirical


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