Posts: 2,036
Threads: 0
Joined: Jan 2003
Will a drilled hole in dry wood shrink? I am making some colored pencil holders for our school, and the holes are big enough now, but will they shrink when it gets more humid out? Inside moisture is around 40% right now, but we are in Wisconsin and it will get damp this summer. It's made out of air dried wood that has dried for 10 years, I'm cleaning out the scrap pile. I'm embarrassed to even ask this question, I should be able to figure it out without asking.
Thanks.
Posts: 29,152
Threads: 1
Joined: Aug 2002
make the hole say 1/32" larger than the pencil and no one will ever notice
Let us not seek the Republican Answer , or the Democratic answer. Let us not seek to fix the blame for the past. Let us accept our own responsibility for the future John F. Kennedy
Posts: 3,066
Threads: 0
Joined: Jan 2004
I have not had this experience so my guess will yield to anyone who has done it, but I suspect the hole in a dry board will distort slightly when that board gains moisture. Whether enough to pinch a pencil? I agree an extra 1/32" would make the issue mute.
Posts: 7,581
Threads: 0
Joined: Jan 2005
Location: New Zealand
03-18-2017, 10:52 PM
(This post was last modified: 03-18-2017, 11:00 PM by ianab.)
The wood around the hole will expand (slightly) if it gains moisture. But this will make the hole larger, and unless you have the hole "interference fit" to the pencil, and need to wax them to slide them in, it wont be enough to notice.
Technically the holes will tend to become oval, because the wood will expand across the grain, but not lengthwise.
But it might be something like (just guessing here) 1/64" difference? As in, don't worry about it.
I have seen the effect with a solid wood table top, that had a hole and glass insert, The board dried slightly more once bought inside, and the hole shrunk slightly, only across the grain. Then the glass was slightly too big for it's rebate. The length of the hole didn't change, but the width did. Hole was a rectangle in this case, but a circle would act in a similar way.
Posts: 1,600
Threads: 0
Joined: Jan 2014
any chance the pencil will "grow", given the same temp/humidity conditions, thereby (up to) doubling your concerns?
Posts: 20,381
Threads: 4
Joined: Sep 2007
Location: CinDay
I am not sure of this, but I have always thought pencil wood to be "pulpwood" which was then formed around the lead, so like plywood, I would think not, but I have no degree in pencil sciences
About, drill a hole in hardwood that is dried to hold pencils. I have done this quite a few times, and I used 1/2" diameter for an average 3/8" #2 pencil. Back in the "Country furniture days" I used to do a replica school house/pencil holder that was a brisk seller. The pencils went in easily, and still stood up straight, but my hole was 1 1/2" deep. That may matter?
Worst thing they can do is cook ya and eat ya 
GW
Posts: 675
Threads: 0
Joined: Aug 2011
ianab said:
The wood around the hole will expand (slightly) if it gains moisture. But this will make the hole larger, and unless you have the hole "interference fit" to the pencil, and need to wax them to slide them in, it wont be enough to notice.
Technically the holes will tend to become oval, because the wood will expand across the grain, but not lengthwise.
But it might be something like (just guessing here) 1/64" difference? As in, don't worry about it.
----------------
+1 The way this was explained to me at Country Workshops in a wet-dry mortise and tenon joint: Think about a circle on a balloon. If you blow the balloon up a bit more, the circle will get larger, not smaller.
(Sorry but "quote" function doesn't seem to be working)
Posts: 7,581
Threads: 0
Joined: Jan 2005
Location: New Zealand
Quote:I am not sure of this, but I have always thought pencil wood to be "pulpwood" which was then formed around the lead, so like plywood, I would think not, but I have no degree in pencil sciences
Pencil I've got here on the desk appears to be 2 pieces of solid wood, glued together with the "lead" sandwiched in the middle.
But I haven't broken out the micrometer to see if it's moving seasonally.
Posts: 2,036
Threads: 0
Joined: Jan 2003
Thanks for all the replies. The pencil (triangular shaped with the corners rounded) will fit in my 27/64" drill index, so I am drilling the next size up, so I doubt there will be a problem-especially with all of your expertise.
Appreciate the advice.
I am making 12 colored pencil holders for our school. Basically a 3 1/2 round block of wood with a bunch of holes in the top. Nothing fancy, although I am cleaning out my scrap bin and gluing walnut, hickory, red oak, and cherry to make the blocks. Probably going to use linseed oil and eventually seal them with shellac. I'll post pictures if they are satisfactory.
Posts: 10,718
Threads: 1
Joined: Jan 2006
Location: Orlando, Florida
Quote: Wrote:I am not sure of this, but I have always thought pencil wood to be "pulpwood" which was then formed around the lead, so like plywood, I would think not, but I have no degree in pencil sciences
Pencil I've got here on the desk appears to be 2 pieces of solid wood, glued together with the "lead" sandwiched in the middle.
But I haven't broken out the micrometer to see if it's moving seasonally.
Decent pencils are solid cedar. If a pencil is 1/4" in diameter, and RH goes from 20% to 80%, then the pencil will gain 0.01" in the tangential dimension. Negligible. I would think the pencil holder will easily accommodate any change in pencil diameter, because it also is expanding as RH expands.
Still Learning,
Allan Hill
|
