LumberJocks

Allowing for Shrinkage and Swelling

  • Advertise with us

« back to Wood & Lumber forum

Forum topic by HorizontalMike posted 418 days ago 606 views 1 time favorited 10 replies Add to Favorites Watch
View HorizontalMike's profile

HorizontalMike

6923 posts in 1539 days


418 days ago

Topic tags/keywords: shrinkage swelling species allowing for

OK, we all know this happens and that we should always allow for this to happen in our projects.

BUT how much:
  • per inch of width?
  • per Species of wood?
  • in the deep South?... of far North?

All of the literature says to allow for this, but I am lost as to finding any reference source that tells me that a 9in(or 4in, etc) wide pine board will need xxx fraction of an inch of space for expansion/contraction.

Help me out folks, is there a source I am missing, you know… that one source that eludes me?

-- HorizontalMike -- "Woodpeckers understand..."


10 replies so far

View AandCstyle's profile

AandCstyle

1286 posts in 882 days


#1 posted 418 days ago

Hey, Mike, did your finger have a spasm causing you to post this innumerable times? LOL

I use the Shrinkulator. Is that what you were looking for?

-- Art

View LoydMoore's profile

LoydMoore

96 posts in 582 days


#2 posted 418 days ago

Shrinking and swelling can be controlled with Viagra.

-- Loyd, San Angelo, TX http:www.moorewoodenboxes.com

View pintodeluxe's profile

pintodeluxe

3318 posts in 1438 days


#3 posted 418 days ago

I made a 42” wide table that shrunk 3/8” in total width. Luckily the breadboard ends were built to handle the movement. So that is about 3/32” per foot of width. Species was quartersawn white oak. Flatsawn boards will move / cup even more. Using Art’s shrinkulator link, a 42” table that dried from 10% m.c. initially, to 7% m.c. would shrink 1/4” for qswo, and 1/2” for flatsawn white oak. So it looks like the calculation is pretty close to what I have observed.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View HorizontalMike's profile

HorizontalMike

6923 posts in 1539 days


#4 posted 418 days ago

MY window never refreshes so I DO NOT know what the hell is going on! My apologizes. I do NOT know how long this will continue… Geez,,,

-- HorizontalMike -- "Woodpeckers understand..."

View HorizontalMike's profile

HorizontalMike

6923 posts in 1539 days


#5 posted 418 days ago

That helps Pinto, but I am looking at Pine movement in particular… if tht is possible…

-- HorizontalMike -- "Woodpeckers understand..."

View pintodeluxe's profile

pintodeluxe

3318 posts in 1438 days


#6 posted 418 days ago

Looks like about 3/32” shrinkage per foot of width in Eastern White pine. This assumes a shift in m.c. from 10% to 7%. This also assumes flat sawn boards.
A good rule of thumb might be 1/8” per foot of width, just to be on the safe side.

Interesting topic.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View HorizontalMike's profile

HorizontalMike

6923 posts in 1539 days


#7 posted 417 days ago

Pinto,
I guessed and left 1/16” gap on my 7 1/2” door panel. Looks like I may be OK.

-- HorizontalMike -- "Woodpeckers understand..."

View redSLED's profile

redSLED

687 posts in 518 days


#8 posted 417 days ago

Wow, a couple of replies from others and myself just disappeared from this thread for no apparent reason.

-- Perfection is the difference between too much and not enough.

View pintodeluxe's profile

pintodeluxe

3318 posts in 1438 days


#9 posted 413 days ago

Here is another wood movement calculator from OSU that offers choices for flatsawn, riftsawn, or quartersawn…

http://owic.oregonstate.edu/wood-shrinkswell-estimator?f=1

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Don W's profile

Don W

14828 posts in 1193 days


#10 posted 413 days ago

redSLED. Mike posted this when the site was having issues. There are several different copies of the same post. I have a post the same day did the same thing.

-- Master hand plane hoarder. - http://timetestedtools.com

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase