"Boxing Out" Timbers from Logs
Advice on the best way to saw or hew frame-building timbers from logs. June 30, 2009
Question
I have a lot of red oak on my property, and would like to use it for the structure of a pole barn. I have read a lot of comments about "boxed heart" posts, and beams. When they used to hew posts and beams, did they make sure the heart was centered? The reason I am asking is because some books I have read say that you can snap chalk lines down a log, and simply cut down to those lines to get the appropriate sized timber. If that is true, they don't seem to be too worried about the heart being exactly centered.
Forum Responses
(Sawing and Drying Forum)
From Gene Wengert, forum technical advisor:
Centered will have less warp indeed. Boxed heart is commonly mentioned in older texts, so I would guess it would have been used in years past.
From contributor J:
"Exactly" centered isn't possible, because trees tend not to be perfectly straight and concentric. Do the best you can, but remember that you're not building the space shuttle.
From contributor T:
I have sawn a couple of barns in the past couple of years. One included about 24 6x6's 26 feet long. The other 10 6x6's 18 feet long. All but four of these were taken from the center of logs, attempting to keep the heart centered. The other four were from a large log that was squared and then quartered. Species used were red oak, poplar, and basswood. Most of the timbers were used within six months of being sawed. Looking at both buildings now, I see little or no evidence of any warp or twist. Almost all show some checking but all are structurally sound.
From contributor A:
In the days of old they hewed logs just larger than the post size. For the most part they kept the heart boxed. It is not hard to take a cross cut saw and broad ax and hew out a timber. The exception to this is boat timbers which they often bent or hewed bowed. As things go there is no real problem sawing out a boxed heart timber. You will produce large amounts of side wood if you do not choose you logs right. The 1 1/2 rule is good for timbers. It keeps the amount of side wood to a minimum and produces the best timbers for the size. To make a 8x8 post take 8 times 1.5 and you get 12 inches dib is the smallest log that will make a clean post. For timbers like 6x12 you can use a slightly smaller log then for a 12x12 but still will need a good log.
Free of heart timbers are good if they are a good ways from the heart. So if you have a 30 inch log and want to cut a 12x12 out of the center and some 6x6's from the outside they will be fine in most types of logs. Splitting a 12x12 into 4 6x6's will not produce good timbers.
