I have been cutting ~9" dia pine logs 16' long that have some sweep in them which limits the size of the beam I can get. I have tried to settle on getting a 4 x 6 (plus a few 1 xs) from them. Invariably, there is a compromise between minimizing the wane and trying to center the pith. In general, what guidelines do you use in making the call?
An example is shown in the pics. The beam is cut to 6.5 x 7 with the planned 4 x 6 marked. The pith will be ~ 0.5 " off center and some wane will remain on the bottom edges not seen in the pics. That's the best I could do given the log I started with. I know the pith will probably wander and the beams may bend on air drying; should I not even bother in trying to cut straight beams out of sweepy logs? There's no plan for the beams yet.
Bob
(https://forestryforum.com/gallery/albums/userpics/13036/center_pith_vs_wane_001.jpg)
Opposite end of log
(https://forestryforum.com/gallery/albums/userpics/13036/center_pith_vs_wane_002a.JPG)
A little wane is allowed by grade rules.
If there isn't a intended use for these yet, try and make them posts instead of beams.
Post can be a little less in quality then beams.
Center the pith as best you can 1/2" out is fine.
Jim Rogers
And as posts, you can reduce the sweep by cutting the logs into 8' to start with.
I have cut a lot into 8 footers so now I am focusing on 16s.
Crooked logs makes crooked lumber every time, Cut them so you have a straight log,
And the best time to do that is when your cutting the tree down ;D
In cutting the log as you have it diagrammed, I will bet the pith will come out of the right side of the log in the last pic. This means that the pith is close to center on the two ends but will exit the log in the middle. This will cause the beam to warp. I think you would be better off to have the ends a little more out of center and not have the pith exit the timber. Keep in mind that when you are trying to get beams out of logs with sweep in them, they are going to warp. That is about all there is to it. You might get the rare one that don't but the odds are not in your favor.
Would I have been better off to cut 1 x 6s out of this log, further adding to my rather large stack? :-\
Bob
Depends on how strait your beams need to be. I make lots of 40' beams that look lots worse than yours but I haven't seen a bulldozer that cares. ;) If you are building a exposed beam house and everyone that enters is going to be judging your beams than yes. If you are building a horse barn they might not judge you as harshly. ;) What you did was fine it just has to do with your end product.
If the beams are useable for a farm outbuilding that would be fine. After all, blue stain creeping in so I would never expect to see them a residence. It'll be interesting to see how they dry.
Thanks,
Bob
Can you use the warp to advantage by putting the crown side up when using it as a beam-- sort of like pre-stressed concrete?
Quote from: dboyt on April 16, 2014, 10:08:16 AM
Can you use the warp to advantage by putting the crown side up when using it as a beam-- sort of like pre-stressed concrete?
May be not so good.
If the side that shrinks some in drying is also the juvenile core, and that side is down due to putting the crown side up, then the beam has the weaker wood (juvenile core) on the tension side where the beam likely needs the most strength.
Well you sure would not want to put the crown down unless your intent is to replicate a sway back building ::)
I've been told, and practice the same, in trying to keep at least 1" off the pith on beams. With the emphasis on a straight beam. Stresses work so differently on logs I'm not sure there is a set rule on this matter. Taking 1" boards are pretty much the go to for me in finishing a beam to a given size unless the cant is behaving.
X2 what peter says ;).
I deal with a lot of junk logs and cut mostly timbers out of them. first logs with sweep get cut down til I have a straight log, sometimes only 4'. I then cut them into 5x7, 7x9 or some other large dimension and sticker them with 2x4s. after about 8-12 months, they'll have moved and cracked about as much as they're going to. I then resaw all 4 sides into a smaller dimension. These sell surprisingly well. and I use quite a few for myself. 4x6 is my most popular size. Not a way to make a living, but a way to make lemonade out of lemons. ;)
I have a few self-imposed rules that make my timbers preferable to my contractor and timber-framer customers:
Grade rules allow quite a bit of wane. I saw my timbers with no wane at all.
I also make sure the pith is close to the centre of a timber. If the log isn't straight I try to keep the pith in the middle 1/3 of the timber.
I saw everything 5" and less in thickness FOHC.
I don't buy logs that have any visible shake, so my timbers don't have shake either.
I can't beat the commercial mills on price, but those simple rules keep the business coming in. We each have to figure out what our particular customers need (even when they themselves don't know).
Quote from: Brucer on April 18, 2014, 12:23:59 AM
I saw everything 5" and less in thickness FOHC.
FOHC? ??? :P
FOHC - Free of Heart Center
Free of heart center