tooth and nail puzzle

[Maxwell Lol]

Can't you just boil the one end? Perhaps wrap the nail with wax. And you can polish the nail afterwards. It rotates and slides back and forth. So most of the hidden surface is exposed.

[George]

Simple, you put the nail in, it will compress the wet fibers to enlarge the 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.

[RicodJour]

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

[Doug Miller]

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.

[Eigenvector]

So what's it on the short axis? That's really the more important of the measurement no?

[RicodJour]

Basing things on your sample size of one seems to be acceptable to you. I wonder what I did wrong? :)

I never claimed it was a systematic test, Doug. I'm relating my experience.

A couple of observations and a couple of questions about your "systematic" approach.

We _are_ talking about a small hole. Please note the subject line in this thread, view the picture of the puzzle, and take it from there. The puzzle uses a 16d nail (0.165") - where did the 5/8" come from? The nail runs along the grain, as did my accident-sample - is that how you drilled your hole? My original point was that the wood will swell in all directions, and will swell more where it is not restrained - i.e. the hole. As Eigen pointed out, the smaller dimension in an elliptical hole is the more critical clearance dimension.

R

[alexy]

Gentlemen, does it occur to you that you may both be right. If one takes a 1/2" offcut from a softwood 4x4 and drill a 1" hole in it, it will almost certainly expand as Doug has predicted.

If, on the other hand, you have a 12" long cutoff from a 4x4 of a not very porous wood and drill a 1" hole through it along the grain, I suspect that it will act as recordjour has predicted. Why? There will be a volume of wood within the sample that does not get much moisture absorption. It will form a "fixed point" from which expansion occurs both outwardly (natural) and inwardly (causing compression of the wood or splitting of the dry wood attempting to contain the expansion. If the expansion is contained, the hole will likely shrink just from the large pressure on the wood that got wet from the inside of the hole.

[Eigenvector]

Hey goddamit this is an argument! No FACTS, MEDIATION, or MODERATION allowed!

Let's get back to it. Your wrong Doug!

[todd]

I'm sorry, but I'm not allowed to argue unless you've paid!

todd

[Eigenvector]

Well for what it's worth I've gone ahead and drilled a 6d nail hole in a

2x4, both along the long axis and across the face and sunk it in water. We'll see what happens in the morning. Who knows, I might just be surprised.

[Phil-in-MI]

Yes, that is what most would do. Just boil the one end.

Aside: the goal is to remove the nail. There is no part of the puzzle's statement, or motivation for anyone to anticipate, that the nail is to be re-inserting into puzzle for re-doing the puzzle. The puzzle's nail just might be a one time use. The entire puzzle just could be a one time puzzle, based on the puzzle's challenge statement.

The heated water is to soften the cell walls for being crushed. Re-hydrating the wood cells is not the goal as water is just so difficult to compress.

Also, the craftsman who made the specific puzzle is (should be?) honor bound to make a puzzle which can be solved. The nail is in a pre-drilled hole, which should have a large enough diameter to avoid any swelling problem.

This type of puzzle is very old. The solution is just as old; tried-and-true as it were.

Phil

[Doug Miller]

This morning, by the way, the dimensions of the hole are 0.674 along the major axis of the ellipse, and 0.626 along the minor axis.

And the bit that drilled the hole slips easily through it -- falls through, in fact, without being pushed or pulled.

I'll conduct further tests with additional samples, and post the results.

And I'm saying that you've drawn an incorrect conclusion from limited experience, a conclusion that you mistakenly believe to be typical.

Please note the point I raised above: it's not possible to draw valid conclusions about the behavior of the material, with samples at such small scales.

To avoid any possibility of confusion, let's avoid using terms such as "along the grain" or "across the grain", etc, and instead make specific reference to the orientation of the tree:

The nail in the puzzle photograph, and of course the holes, is parallel to the trunk of the tree; that is; axially with respect to the growth rings.

Is that how your sample hole was drilled?

My test hole was drilled radially with respect to the growth rings.

Subsequent tests will use holes drilled radially, tangentially, and axially, to compare the effects.

But that is not correct. As another poster pointed out, when a substance expands, any two points in it get farther away, without regard to whether they are separated by solid matter or air.

Basically no change -- a difference of 0.002" (three-tenths of one percent) could easily be a measurement error.

[Doug Miller]

ROTFLMAO!

[Doug Miller]

Measurements after approximately 13 hours immersion: Major axis (tangential to growth rings) 0.674" Minor axis (axial to growth rings) 0.626"

The difference of 0.002" (0.3%) axially could easily be a measurement error, either dry or wet -- the difference of 0.046" (7.3%) tangentially I claim to be significant.

[George]

How about if there were an incompressible object in the hole? Think the wood might squash before the steel?

[Eigenvector]

I find it interesting that I got such different results than what Doug got.

2 holes, one across the grain of a 2x4, one with the grain. In both cases of overnight soaking in water the hole was SMALLER. The hole across the grain was barely smaller, probably less than 5%, the hole with the grain was visibly smaller and very distorted too.

Sorry, I'm unconvinced that the hole would get larger.

[George]

Don't forget the nail. The wood will contract against itself as it dries once again, but there's nothing to pull against in the hole. Bowl turners take advantage of this by turning green and allowing to dry, which results in less contraction across the grain than a board.

Owners of the Hoadley book will find some interesting information on page

169 or thereabout, depending on edition. Round tenons.

[BillinDetroit]

Phil, are you suggesting that we set fire to the wood? ;-)

Bill

[Phil-in-MI]

{taking tooth pick out of mouth}

{while looking at end of tooth pick} Well Bill, one could do that, but with it being soaked in boiling water, might take a bit... and with this heat wave as it is....

{pats down pockets for new toothpick} But you know, there's been a lot flame in this thread already. and what with Global Warming and all.... Sure be a lot of bother to set the wood on fire in this heat wave....

{un-wraps new toothpick from greasy spoon} Yes, I think I am going to vote we just forget about this thread, now the nail is out. Hell, with this heat wave, the Dog don't even want to play catch with that old piece of scrap wood.

{sticks toothpick in mouth, and sips a bit of Ice Tea.) Gosh, this is sure a hot spell we got here. Yes, Bill, they's been way too much flame in this thread. All that passion and argument over a piece of scrap wood and an old nail.

But, well you know, if you are going to fire up the BBQ anyway.... What the hell..

Take care Bill, stay cool.

Phil