I am not to knowledgable about lumber and the various cuts of lumber. I was in HD today and I always walk past the cull lumber cart. I have gotten some good wood there before, including some small pieces of walnut. Today I saw this large piece that looked like it was a 8x6 timber. It didn't have any obvious flaws, however the end grain was very unusual.  It was the center of the tree.

I have rarely seen this and wondered if it was NOT a good piece to use and that was why it was in the cull lumber. Is there reasons why you wouldn't want it?

The pith is what causes cracks. It shrinks first and therefore cracks radiate from it. Other end cracks are causes by the outside drying faster than the inside.

Next time you're in HD check out the stack of 4X4s.  Everyone is the center of a tree.  They are harvested on tree farms of quick growing trees.

 

1 hour ago, Gerald said:

The pith is what causes cracks. It shrinks first and therefore cracks radiate from it. Other end cracks are causes by the outside drying faster than the inside.

So this is a bad choice because of cracking. I do like to turn pieces like that and not had any bad experiences yet. Of course my pieces are small and well dried before I turn them.

 

Thanks Gerald

2 minutes ago, HandyDan said:

Next time you're in HD check out the stack of 4X4s.  Everyone is the center of a tree.  They are harvested on tree farms of quick growing trees.

 

That sure make a lot of sense, thanks Dan

15 hours ago, Ron Altier said:

So this is a bad choice because of cracking. I do like to turn pieces like that and not had any bad experiences yet. Of course my pieces are small and well dried before I turn them.

 

Thanks Gerald

I have turned and left the pith in on green wood . Use CA to saturate the pith inside the bowl and usually that saves it. With dried wood it can work but more likely to have cracks extending further into the wood.

Good Luck

Wood movement 101:

• Wood moves in two ways, radially and tangentially.   Radial means from the center out, tangentially means from around the growth rings
• Wood species move about twice as much tangentially as radially when they absorb or desorb moisture
• The distance around a ring (tangential) is directly proportional to how far it is from the center (radial) [Circumference = 2*pi*radius]

Therefore, if left to dry, there will be one or more pie-piece shaped cracks open up.  You see this all the time in firewood that's not been split.

 

The pith, while weak, does not cause the problem.

 

 

Now, on the other hand, if you rip out a section containing the pith (center), you can end up with two quarter-sawn pieces of lumber.   These are very stable and not prone to warp since most of the movement is in thickness, not width, and not a little of both that can cause cupping.  I have done a number of utility projects where I buy pithy 2x12 SYP and rip it down to 2x4 or 2x6 or something in that range and end up with quarter-sawn or rift-sawn stock.  In addition, 2x12 is generally used for things like floor joists and tends to be less knotty than other stuff.  Menards carries #1 SYP in those sizes.

 

 

 

 

1 hour ago, kmealy said:

Wood movement 101:

• Wood moves in two ways, radially and tangentially.   Radial means from the center out, tangentially means from around the growth rings
• Wood species move about twice as much tangentially as radially when they absorb or desorb moisture
• The distance around a ring (tangential) is directly proportional to how far it is from the center (radial) [Circumference = 2*pi*radius]

Therefore, if left to dry, there will be one or more pie-piece shaped cracks open up.  You see this all the time in firewood that's not been split.

 

The pith, while weak, does not cause the problem.

 

 

Now, on the other hand, if you rip out a section containing the pith (center), you can end up with two quarter-sawn pieces of lumber.   These are very stable and not prone to warp since most of the movement is in thickness, not width, and not a little of both that can cause cupping.  I have done a number of utility projects where I buy pithy 2x12 SYP and rip it down to 2x4 or 2x6 or something in that range and end up with quarter-sawn or rift-sawn stock.  In addition, 2x12 is generally used for things like floor joists and tends to be less knotty than other stuff.  Menards carries #1 SYP in those sizes.

 

 

 

 

 

Thanks, very good explanation and pictures.

In my 20 years of woodworking, this is the first time I have ever read or heard that the pith does not cause the splitting.  Everything I have ever read or heard is to remove the pith as soon as possible.  I have removed pith from many trees and never had a problem.  If I leave the pith, it always splits.  Maybe, it it the high humidity here.  Interesting info.

I just looked at this again and the article @kmealy posted is in reference to flat lumber and you will note none of the pictures show a cut with the pith left in. I have cut the pith out of many logs and when it dries that piece (from 1-2 inches thick) always cracks thru the the pith. In turning things are a little different . The CA is a solution on green wood turned to finish. If the wood is left whole and allowed to dry before turning the crack will be thru the pith. Now there are exceptions to everything and I have had some logs for 3-5 years and no crack.

Thanks, Gerald.  I was surprised when I read Keith's statement.  I guess I misread.  Like you, I have had some very short pieces with the pith that did not split and others that did.  I had kept a bunch of Christmas tree stumps to make toy trains and they all split.  Just before Christmas, I go to sales yards to gather a few of the pieces they cut off.  I am about to make one in  a week or so and most of my pieces have split.  I will work around them.  I will remove the pith, joint the pieces and glue it back together to turn.  But, for years I have just used my recip saw to remove the pith.  It works very well after the pith is removed.