tooth and nail puzzle

Page 1 of 2  
Did anyone ever find the correct answer to this puzzle?
http://answers.google.com/answers/threadview?id44364
We just came across this puzzle at work.
Thanks,
Peter
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry, I wondered into this NG from rec.woodworking NG.
This is an old-tyme puzzle, that is normally phrased How-did-the-nail-get-there-in-the-first-place. Lots, and lots of posting on this puzzle, and the solution along with it's companion, the wood pencil in the wood block on Wood Working forums, NGs and so forth.
(the solution was on the Public TV show, The Woodwright's Shop with Roy Underhill a few seasons ago.)
Soak the wood in boiling water for several minutes. (actually, a whole lot longer than several minutes!) Compress one end (section) of wood in a wood vice, and squeeze to compress. (Takes a lot of effort, vice must be bolted to workbench. A "put-your-back-into-it" type of effort.) Wood will remain compressed until re-immersed in boiling water. Normally, will return to original size.
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.) 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.)
Phil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sorry, I thought this was the rec.puzzles NG I didn't notice this was the rec.woodworking NG.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 6, 10:55 pm, "Phil-in-MI" <NO Spam &

Thanks for your reply and sorry if I posted in the wrong newsgroup. The puzzle was posed to us as "how do you get the nail out of the block?" I wonder if boilng and a vise would work for that too?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Peter:
Yes, it will.
BTW, what I meant to say in my last post: I apologize for the tone of my reply, which was aimed at non-woodworkers. In this NG my reply to your original post should have been: Boiling water --> squeeze in vice --> boiling water.
Everyone who follows this NG would have already known everything else I wrote. I suspect many who read this NG were insulted by the tone of my choice of words.
Phil

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 6, 10:51 pm, "Phil-in-MI" <NO Spam &

Why wouldn't the nail rust and stain the wood? That would certainly point towards water being involved in your...errr...solution. I suppose the nail could be stainless steel, but I've never seen a 16d common stainless nail.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

it all but impossible to extract.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Because the wood swelling will make the holes *larger*, not smaller.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 7, 11:05 am, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Why wouldn't the wood swell in all directions?
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It will, and take a bit of compression set before it contracts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I don't understand what you mean. Could you explain?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

way. It will then contract as it dries, (anisotropically, for Doug) pulling away from the nail a bit. It'll be a bit more than if you hadn't had to compress the wet fiber, because you've altered the structure a bit. Wood folks call it compression set, and it's the principle behind bending which stays put.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It does -- but it does not swell *uniformly* in all directions, because wood does not have a uniform structure. Its fibers are long and narrow, with the long axis parallel to the trunk of the tree. The extent of tangential dimensional change (parallel to the growth rings) in response to changing moisture content is, as a general rule, approximately double the extent of radial dimensional change (perpendicular to the growth rings), and either one is several orders of magnitude greater than the axial dimensional change (parallel to the trunk of the tree).
To put it in somewhat simpler terms: when a piece of wood absorbs moisture, it gets wider. It also gets thicker, but proportionately by only about half as much as it increases in width. The length hardly changes at all.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It does -- but it does not swell *uniformly* in all directions, because wood does not have a uniform structure. Its fibers are long and narrow, with the long axis parallel to the trunk of the tree. The extent of tangential dimensional change (parallel to the growth rings) in response to changing moisture content is, as a general rule, approximately double the extent of radial dimensional change (perpendicular to the growth rings), and either one is several orders of magnitude greater than the axial dimensional change (parallel to the trunk of the tree).
****OUCH! My head hurts!
To put it in somewhat simpler terms: when a piece of wood absorbs moisture, it gets wider. It also gets thicker, but proportionately by only about half as much as it increases in width. The length hardly changes at all.
****Thanks... from the old blonde broad.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 7, 12:10 pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

There's no need to put it more simply - I'm more than passably familiar with wood properties. It sounds like what you're saying - correct me if I'm wrong - is that the wood fibers around the nail are somehow different than the wood fibers not next to the nail. The wood fibers run in the same direction, and the hole is drilled in the same direction as well. How can the wood fibers react differently?
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Quite the contrary. I'm saying that they're all the same.

They don't.
Suppose for the sake of illustration that the width of the board increases by ten percent when it's saturated with water; suppose further that we have a 1/4" diameter hole drilled in the middle of a board that's 2.25" wide (1" on each side of the hole).
The board swells to a total width of 2.25 + 10% = 2.475". The wood to the left of the hole started out 1" wide, and swells 10% to 1.1". So does the wood to the right of the hole. Total 2.2" left and right. Leaves 0.275" for the hole, no?
It's *exactly* the same principle as heating a piece of metal to enlarge a hole for making a friction fit: metal expands when heated, and wood expands when it gets wet. Holes in metal get larger when heated, and holes in wood get larger when wet. The only difference is that since wood does not expand at the same rate in the x and y axes, due to its non-uniform structure, circular holes in wood become elliptical when they expand, instead of remaining circular as do holes in metal.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 7, 2:01 pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

I'll argue my point with a very simple test that you can do for yourself. Drill a hole the exact size of a nail in a piece of wood, drilling along the grain. Soak the wood overnight. You don't have to boil it. Try to insert the nail the next morning. The wood will have expanded, and the hole will have gotten smaller, not larger. The hole may not be perfectly round, but the net area of the hole will be smaller. I've done this. Try it, you'll see.
Simple practical tests outweigh theoretical ruminations. Ask Richard Feynman...well, he's dead, but he'd agree with me.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Nonsense.
Pardon me for being very skeptical of your claim to have actually done that. I'll perform my own test and report the results.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Jul 7, 7:24 pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Which part of my experience is nonsense? Like I said, try it for yourself.

Please do. I wouldn't have it any other way.
BTW, the test was an accident. It was an offcut piece of red oak with a drilled hole that I'd left outside - yes, I know I should clean up more carefully. The piece was outside for about a week and there'd been only a day and a night of rain I think. Out of curiosity I stuck the same bit into the hole, or tried to, and it wouldn't fit. I could spin the bit in a little, like I was drilling it, but from your description it should have slid in easily as the hole could only get bigger in all dimensions. It was only a partial test as I didn't try the bit after the piece dried out - I just threw it away.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

First, in assuming that a sample size of 1 is sufficient for generalization; second, in failing to understand all the factors involved -- see below.

My experiment is already underway. I drilled a 5/8" hole in a small scrap about two hours ago, and dunked it. I measured it with a dial caliper just prior to immersion at 0.628" diameter.
I just fished it out -- the hole is visibly elliptical already, and measures 0.661" along the long axis, parallel to the growth rings. Note that this absolutely contradicts your claim that the hole will shrink.
I'll check it again in the morning.

In other words -- no systematic testing conducted, just a conclusion drawn from examining a sample size of one piece.
Did it occur to you that small holes can easily be obstructed by only a handful of wood fibers that swell into the hole? The only *valid* test is by measuring a hole that's considerably larger than the grain of the wood.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.