Shrinkage

[Bill]

I've been interested in making a workbench ever since Lew introduced me to that octopus (inside joke).

It was revealed to me in my reading (here and elsewhere) that if I tote home some SYP from Home Depot and create M & T joints from it, then my tenons may be in for significant shrinking.

I was originally planning to use "keyed" M&T joints, now I'm thinking "wedged" M&T joints may help deal with this detail.

Comments welcome.

Hey, it's almost spring!!

Bill

[SonomaProducts.com]

my

Unless you are starting with wet lumber (like just cut from the tree) or your tenons are huge (like a foot or two across) you shouldn't have any problem with wood movement and no need to account for swelling or shrinkage. Movement is on the order of a few percent and isn't typically accounted for within the context of a single joint. If a 3" x 1" wide tenon swelled in a tight mortise it wouldn't change enough to hurt anything.

Use any type of M&T joint that you desire.

Also, to avoid shrinkage just stay out of the pool.

Finally, can you really get SYP at Home Depot? They only have crapola Ponderosa and maybe ESLP if you really want to pay, but nothing like real Pine.

[Bill]

Thank you. Here is a link to rhw SYP I saw at HomeDepot:

[J. Clarke]

that what HD stocks is regional--you'll get different species in the south than in the north and in the east than in the west.

[Swingman]

Just be sure to get KD "Kiln Dried" stock.

#2 SYP KD is generally between 14% - 19%. Ideally you want it closer to (or under if possible) 12% for your task, so use a moisture meter to chose your stock (MC may vary wildly within the same stack). Acclimate it in your shop for a few weeks, or longer the higher the MC.

Basically, start out with as low a MC as you can, then once it reaches EMC for your environment

[Larry Jaques]

designation.

or KD-HT? What's The Difference?

When choosing whether to stamp your product HT or KD-HT it?s important to remember the difference between the two stamps . Heat treated lumber may be marked as KD-HT or HT. If marked KD-HT, the lumber is being guaranteed as 19% or less moisture content and that it has been heat treated to at least 56 degrees C (minimum of 133 degrees F) for at least 30 minutes at the lumber core. A mark of HT signifies that the lumber has been heat treated to at least 56 degrees C for at least 30 minutes at the lumber core, without moisture content designation.

[Doug Miller]

Indeed you will, if you cut the joints immediately. On the other hand, if you stack and sticker the wood in your shop so that air can circulate around it, leave it alone for two weeks, and *then* cut the joints, you should be fine.

Can't hurt, but it's probably unnecessary work. Start with the driest wood you can find, let it acclimate to the environment it's going to "live" in before you cut any joinery, and I doubt you'll have any problems.

[dpb]