quartersawing yield charts and pictures

[Dan_Shade]

i posted one of these in Stew's thread, here are the rest I did.  Just some general observations I have come up with drawing pictures up. 

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log diameter:                                      18               19
board feet per linear foot                      12.5            13.4
international scale per linear foot          14.5           16.2

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log diameter::                                      20              21
board feet per linear foot                      14.5            15.6
international scale per linear foot         18.1             20.0

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log diameter                                       22              23
board feet per linear foot                      16.6            17.6
international scale per linear foot          22.1            24.0

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log diameter:                                     24              25
board feet per linear foot                      22.9            24.4
international scale per linear foot         26.5            28.8

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log diameter:                                    25              26
board feet per linear foot              24.4 25.6
international scale per linear foot         28.8 31.3

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log diameter:                                    27             28
board feet per linear foot              31.0            32.9
international scale per linear foot         33.9            36.5

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log diameter:                                    29             30
board feet per linear foot              34.6            40.5
international scale per linear foot         39.2           42.1

[MemphisLogger]

I like your diagrams, Dan.

I make 'em and use 'em to work out potential yield strategies with all my big log clients.

This diagram was for a 10' long, 60" diameter Pecan. (We ended up cutting another foot off the butt to get past the weedeater guard put around the tree when it was 20 or so.)  :'( :

The customer really wanted all plainsawn material but needless to say, we couldn't grade saw this 9000lbs+ log on our LT-30.  :-[ :D

The diagram really helps the customer "see" the options.



The actual log had quite a bit of "hourglass" to it and the deep convolutions typical of large Pecans. Computer says it was supposed to have 1400+ feet in it but we ended up with around a thousand after heavy slabbing, pithing and trimming (BBQ shop trades good for Pecan  ;D). The undecided quarter ended up being QS at 5/4. The customer chose the thicknesses. If I'd been sawing it for myself, I'd have sawed it thicker and and taken my waste at the planing bench. :-\ 

     

[SwampDonkey]

There's also waste from the saw, so you have essentially 'diminshing returns' that take away from the recovery. ;)

[Dan_Shade]

Scott, I believe this is the best way to visualize things, but it doesn't account for non-concentric growth rings, or tension, or taper, or other variables

my board thicknesses account for the standard 4/4 and saw kerf, what I don't have accounted for is what I screw up!

[MemphisLogger]

I set my drawing program (TurboCad) to a 1/8" thick line to over-account for the kerf loss.  ;D

The presentation of the hypothetical yield/sawing strategy is always given with a disclaimer about logs never being perfect cylinders.  ;)

When QSing our own big logs, we fly by the seat of our pants--switching thickness as we (the log) please(s).

The diagrams really come in handy only for customers' logs when they won't be able to be present for the sawing. Here it really helps them get an idea of what they will (might) be getting.

It also helps with getting my cousin going in the morning--if I hand him a diagram, he and the Towmotor get it done quick (and leave me out of it). If I don't give him a diagram, he ends up coming and getting me every quarter to tell him what to do  :