Quartersawn Lumber and Math

[Bremen]

Dunno if anyone will find this of interest or value, but.. I was playing with some learn-math type software while simultaneously wondering how wide a Q-sawn board I could make from some trees.

I make no guarantees on the math, but it seems right to me. Why yes, I am a dork.

 

[Tom Dunlap]

I'm having a hard time plotting the three axis back onto the curve.

Can you take a theoretical log and plot out the yield?

You should post this to this forum also:

http://www.woodweb.com/cgi-bin/forums/sawdry.pl


Tom

 

[Bremen]

If by "yield" you mean the largest dimension of a quartersawn board that can be made from a log of a given size, and you know the board thickness and angle you want, then yes it can be done.

Ex: I've got a 24" log and i want some 8/4 (2") boards that are truly (75-90 degrees) quartersawn.. How wide will they be? The answer per my numbers (somewhat approximate due to estimating bark and sapwood) would be ~6.6 inches

I do not make any attempt to figure out how many of these could be removed from a log (always at least 4 though), or what other sizes would also be possible in the same log.

If this is what you are asking, I can post formula and/or graph later. I'm a bit busy right at the moment.

 

[John Paul Sanborn]

So is the reason they call it a cant is because you cant get much yeild from it


after the rift sawn is taken from the cant, what is the average waste in a QS log compaired to an average PS log?

 

[Bremen]

Good question. And one I'm not qualified to answer. It would certainly vary somewhat depending on dimensions, etc.