Replies

1. 
   StanleyNiemiec | Mar 30, 2002 05:58am | #1

   If the wider boards you will obtain are flat sawn (ie tangential grain) then it is likely that you will have to deal with cup.  And with cup come split and sometimes excessive planer shavings, or resawing off the headrig.  Now if you can get wider radial/quartersawn/VG stock, then it might be worth fooling with!

   It's been a while since I been involved with woodmizers, so I cannot remember mill specifics.  I wish I could help you more.  Doesn't woodmizer have a site where you might better address this query?

1. 
   JohnKrist | Apr 01, 2002 07:08pm | #2

   Thanks for the reply.

   Now that I think a little more, its not so much a question of what the best cutting pattern for the best yield (a WM has such a thin kerf that there is little waste), but what should I plan for in projects. I am thinking about half the log in wide-as-possible cuts, then the rest in 6 to 12 inch widths. I have a great system of drying with ratchet straps and 4x4's that applies great pressure, so drying has not proved too much of an issue.

   Thanks for the input.

   JK

1. 
   ScottInMadtown | Apr 02, 2002 10:50pm | #3

   John,

   Your method of drying using rachet straps sounds very intriguing.  If I were you I would send that in to FWW as a tip of the month and see if you can't win that sweet Lie-Nielsen plane!  If you don't want to submit that, I'm sure the posting board here would love to know more about your technique.

   Scott

1. 
   SCFrankland | Apr 02, 2002 11:05pm | #4

   John I second Scott's suggestion that you should post your idea with more detail here. I use a chainsaw mill to make most of my board and I am always looking for better ways of drying lumber.Scott C. Frankland

   Newfoundland Wood Worker

1. 
   JohnKrist | Apr 03, 2002 05:33am | #5

   Gee, I could really use that LN plane...I'll send FW the tip and see what happens. I'll post the plan after the submission. Thanks for the idea.

   JK

2. 
   StanleyNiemiec | Apr 03, 2002 06:36am | #6

   I spent some 7 years working at the Forest Products Department at Oregon State University in a quasi-extension role.  I have a fair amount of contact with the Drying expert as his office was next to mine.

   He and other wood drying specialists generally do not like racheted hold downs because top pressure is non-uniform (as the wood drys/shrinks the pressure diminishes until you crank it down again).  Part of their objections were this method did not prevent crook and it was thought to increase cracking in cupped boards.  They also indicated that the actual force you obtained using straps was pretty low.

   The best solution they had was concrete weights/slabs on top so that you had >100 psf. 

   This is not easy for small operations so maybe your approach is the best available (albeit not ideal).  Were I to do it, I would probably get a load of cement blocks as many as I could afford and be able to move concentrated above the stickers.

1. 
   JohnKrist | Apr 03, 2002 09:37pm | #7

   (A little long, but some useful stuff, I think)

   Thanks for the feedback. I understand the comments about weighting with concrete (I've tried blocks); here's why I think straps work better.

   The straps are rated about 450 lbs each. Now, here I'm not sure of my mechanics, and I am sure someone would like to offer an opinion, but when I really crank three straps down on a 4x4x8' as far as it goes, I can apply either 450 lbs or 1350 lbs, depending how the forces add. Here're the contrasting points with using blocks:

   Because the 4xs are loaded just at the end of the stacking its really easy to position the force where I want it over the stickers, or adjust it once done

   I can get the stickers so tight that they can't be moved even with a hammer.

   If I take just the low end of the force one 4x4x8 would give me 187lbs./f2, obviously more if the forces add.

   I can't quite express why, but a strapped stack seems much more stable and less prone to being knocked out alignment

   I can easily add more boards to the pile without having to pull off dozens of blocks

   I can also easily shim the 4xs to make up for differences in board thickness, but I really focus on getting 1” boards to start. I will stack odd thicknesses in a separate stack (with stickers that don’t reach into the other stacks) and shim at the end with just a small board or two.

   Blocks shed a lot of grit, are heavy to move and take up huge space when not being used

   I fully agree that the straps need tightening as the pile dries. However I have never had to do it more than twice, and that is only in about the first month or two of drying. I recently broke down a pile of ash that had been drying in the shop attic for about a year, and the straps were still tight, so tight I had to use the ratchet to back off the tension rather than just pushing down the catch.

   Probably most important of all, the straps add force if the boards cup or bow. A block can push with at most its weight, while straps push harder as the boards push. The very best way to eliminate cupping in my experience it to get the wood strapped up within a few hours of cutting. Also, I do watch the piles and notice that when a board cups some, it will often flatten by itself, regardless of whether or not I crank some more. Cracking make sense to me if the board is cupped before strapping and has had a chance to dry.

   I’ve also never had a board crook; weight is weight, so I don’t see how blocks would be more able to prevent wood from moving. Off hand, it seems like there was not enough weight to keep it still.

   One caveat: the stickers and supports have to be dead flat. I take the time to run the bottom 4xs through the planer and make sure the stickers are all exactly 1”. I always sight down through the stack to make sure that all the boards are straight. I also use a level to make sure that supports are all flat to each other. I found out the hard way when a bunch of boards came out twisted when they looked straight in the pile; the supports on one end had a lower bias that transmitted through the pile. After some practice I could really get the hang of ferreting out anything that was not straight when I look down the edges.

   Lastly, 4xs are free from the dump and straps are unbelievably cheap at $15 or so per 4 pack at HD. Again, if my mechanics are right that would be 1,800 pounds (4 x 450) of force vs. whatever blocks cost-say 1,800/40 lbs a block x $2 a block is $90. I can use the straps for other things too.

   Thanks for all the comments and thoughts.

   JK

    

    

    

1. 
   StanleyNiemiec | Apr 03, 2002 11:47pm | #8

   John:

   A lot of what you say is absolutely true especially when it comes to grit and convenience, etc.

   I also appreciate the dialog because I hope to have my own stacks in the future and I want to make sure that I do not overlook the obvious.

   Help me through this cuz I sometimes get confused on these issues as well.

   If each strap is rated at say 500# then that is the total force being applied downward.  If you have 3 then you have 3 times 500# or a total of 1500#.  That force is not distributed over the entire top surface but only on the 4x4 bunks.

   I'm guessing that you are running these 4x4's across the pile.  Thus a 4x4 that is 4 feet long has a contact surface of 3.75" x 48" or 108 sq inches.  If the bottom bunks are immobile and are supporting the weight of the stack then the 500# of strap force, in my thinking, is applied to 108 sq. in. so that you have a force of about 2.77 psi or 667 psf per strap at full tension.  That is more than I would have expected.

   Just for whatever, I estimated the shrinkage of an 8' high stack of 4/4 white ash (flat sawn).  If you are using stickers that are 0.625" thick, you have about 60" of actual wood.  If you can air dry it to 15% the amount of shrinkage in the stack would be about 2.4".    I would guess you have about 1500 bdft in the pile with an initial weight of maybe 7500#.  The weight of the pile will keep the bottom boards flat so the only ones you are concern with will be those on the top. 

   It just might work!!  The only thing that I would do is probably check the strap tension more often.

2. 
   JohnKrist | Apr 04, 2002 03:04am | #9

   Nice thoughts and questions. My limited knowlege of mechanics seems to agree.

   "If each strap is rated at say 500# then that is the total force being applied downward.  If you have 3 then you have 3 times 500# or a total of 1500#.  That force is not distributed over the entire top surface but only on the 4x4 bunks."

   The first layer of boards really acts to spread the force out throughout the pile, and if the stickers are all identical, and the mill was accurate, the force gets spread pretty well. The top courses are the places I put low grades and variable thicknesses, since I can easily shim the top flat. I used to use three straps per every column of stickers every two feet; now I just use straps every four feet, since the force is really well spread and the stickers are d*mn tight all the way around.

   "Just for whatever, I estimated the shrinkage of an 8' high stack of 4/4 white ash (flat sawn).  If you are using stickers that are 0.625" thick, you have about 60" of actual wood.  If you can air dry it to 15% the amount of shrinkage in the stack would be about 2.4".    I would guess you have about 1500 bdft in the pile with an initial weight of maybe 7500#.  The weight of the pile will keep the bottom boards flat so the only ones you are concern with will be those on the top."

   If the wood is going to go wild, it will in the first couple of months. At the heights of the stacks that can be fesibly loaded by hand, say no more than 6' high, the twisting, cupping, and general misbehaving force is pretty substantial, and the weight, while helpful is not sufficient alone to keep even the bottom courses flat. That is why I strap the wood ASAP after cutting, while the fiber is as wet as possible, and really max out the straps. This force is active in the bottom boards too, and I have seen boards work together to pick up whole corners of stacks as they dry, only to go down later. I try to stack in alternating heart up/heart down when I can to counteract this possibility, but often settle for stackng the boards as they came off the mill, which ends up about the same.

3. 
   TooManyTools | Apr 07, 2002 05:04am | #10

   Haven't seen a picture of how your strapping those piles but if your running them around the 4x4s, ie, each strap goes under the bottom over the top and back to the ratchet you are getting twice the rated tension per strap.  Those straps are generally rated for single line pull so when you double you get twice the strap tension as a load transmitted to your 4x4.  Probably some friction loss and it is difficult to load those cheap straps to the rated tension unless they are commercial load binders in which case you won't buy them 4 for $20.  Also if, as I assume, you have a 3 4x4s top and bottom with a strap around each end of each pair of 4 bys, then your total compressive force is 6 straps x 2 lines per strap x 450 or 5400 lbs.

   Edited 4/6/2002 10:53:25 PM ET by JANATION

4. 
   JohnKrist | Apr 07, 2002 05:59pm | #11

   One of the great things about this community we have is how great it is to hear from folks who really have the last word. Now it really starts to make sense that when a stack is stapped down tight, I really really can't move the stickers. Just a few hundred pounds (which I thought developed) never would be enough to make the piles that tight, I kept thinking.

   Friction is actually a real issue. I am finding that it pays to put some notches around 4xs where the straps pass to keep the straps from hanging up as I ratchet the straps down. I suppose that the force gets added somehow anyway, but I suspect that some tension would get lost as the strap adjusted around the 4xs and became un-hung up.

   Thanks for the professional analyses.

   JK