Official Luthiers Forum! :: View topic

Thanks you guys. I think our two industries may have different terms for the grain so let me try to get on the same page with ya. In aircraft lumber terms, we define:

1. "run-out" as angle of the face-grain with relation to the edges of the board along its length. I cut areas of run-out off a long board; ie the grain runs perfectly parellel to the edges along the entire length of the finished spar.
2. "slope of grain" as the general direction of the longitudinal fibers of the wood. I'm gathering that this term is the "runout" to luthiers. Cause: the twist of the tree as it grew. We are limited to 1:15 on the slope. I grade out any wood in excess of this 1:15 and prefer no slope down the entire length of the board.
3. "vertical grain" as the angle of the annular rings from the face of the board when viewed from the end grain. We consider anything from 45 degrees to 90 degrees to the face to be vertical. My cants are quarter sawn so I get a lot of 90 to 80 degree which is my personal favorite. On the cants that are 60, 50, 45, I run the cant through the mill on an angle to get back to at least 70. I don't know what your limits on vertical are.

do you mill from a split face to minimize runout?

Author:	Picea Sitchensis [ Mon Aug 18, 2008 7:09 pm ]
Post subject:	Help! Sitka Spruce
I'm new to the board and need your help. I own and operate an FAA Repair Station for wood aircraft structures and I buy fairly large quantities of vertical grain Sitka Spruce for my spars and other components. I buy cants from a mill in Alaska and then mill it to spec here at the shop. I sticker it up in my hanger and season dry it. In every load I receive, there is always lumber that I can't use and this last batch is full of bearclaw. Can you guys use it? I can't. Although bearclaw is not a "flaw" according to the MIL-SPEC, my customers don't like to see it in their spars. I've probably got 15 to 20 pieces, 4/4+ x 8" x 18 foot with moderate bearclaw. Grain count is 32 to 50 or so. Should I cut it up and sell it on Ebay? What would be the best way to get it into the hands of people who can best use it? Thanks for your help.

Author:	Clay S. [ Mon Aug 18, 2008 7:17 pm ]
Post subject:	Re: Help! Sitka Spruce
Do you check the wood for runout when you make spars? (I would think you would) If it nicely quartersawed and doesn't have too much runout I'm sure many of us will be interested.

Author:	Don Williams [ Mon Aug 18, 2008 7:27 pm ]
Post subject:	Re: Help! Sitka Spruce
Sitka is my favorite wood, and especially if it has bearclaw. How much $ for it?

Author:	Howard Klepper [ Mon Aug 18, 2008 7:29 pm ]
Post subject:	Re: Help! Sitka Spruce
The short answer is yes. As has been asked already, do you mill from a split face to minimize runout? I think a lot of folks here would be interested. Bear claw is acceptable and is desired by many for guitar tops. We also need clear, straight grain and consistent grain spacing. It can vary some across a board, but sudden changes are not desirable. 4/4 x 8" boards 22-24" long or 44-48" long would interest me.

Author:	Picea Sitchensis [ Mon Aug 18, 2008 9:32 pm ]
Post subject:	Re: Help! Sitka Spruce
Thanks you guys. I think our two industries may have different terms for the grain so let me try to get on the same page with ya. In aircraft lumber terms, we define: 1. "run-out" as angle of the face-grain with relation to the edges of the board along its length. I cut areas of run-out off a long board; ie the grain runs perfectly parellel to the edges along the entire length of the finished spar. 2. "slope of grain" as the general direction of the longitudinal fibers of the wood. I'm gathering that this term is the "runout" to luthiers. Cause: the twist of the tree as it grew. We are limited to 1:15 on the slope. I grade out any wood in excess of this 1:15 and prefer no slope down the entire length of the board. 3. "vertical grain" as the angle of the annular rings from the face of the board when viewed from the end grain. We consider anything from 45 degrees to 90 degrees to the face to be vertical. My cants are quarter sawn so I get a lot of 90 to 80 degree which is my personal favorite. On the cants that are 60, 50, 45, I run the cant through the mill on an angle to get back to at least 70. I don't know what your limits on vertical are. do you mill from a split face to minimize runout? No. In the lengths I use (18 and 20 feet), the cants are ripped from full length quarter rounds. This is why I have to check the slope on each piece--all along the piece. I do it by cutting a 1/16" slice off the edge grain and bending it until it breaks (this would be kinda tough to do on a 1/4" wide piece; mine are an inch wide). The break will follow the slope. I'm guessing this is the same as you guys using a "split" piece because, obviously, it will split perfectly down the slope. We don't have this luxury and have to take what we get because of the long lengths. They [lumberjacks] are supposed to cut the first 8 to 10 feet [from the ground] of the tree off. I understand the base of the tree will have excessive twist to it. I have seen slopes of 1:5 at one end of a board and zero at the other and also different slopes from one EDGE to the other. What a pain! Anyway, I have no idea on the price. I'll work it out with you. I just want to get enough for it that I can buy more aircraft grade to replace this batch.

Official Luthiers Forum! http://w-ww.luthiersforum.com/forum/

Help! Sitka Spruce http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=18444	Page 1 of 1

Author:	Chas Freeborn [ Tue Aug 19, 2008 3:11 pm ]
Post subject:	Re: Help! Sitka Spruce
Where are you located? -C

Author:	fryovanni [ Wed Aug 20, 2008 9:59 am ]
Post subject:	Re: Help! Sitka Spruce
Code: Thanks you guys. I think our two industries may have different terms for the grain so let me try to get on the same page with ya. In aircraft lumber terms, we define: 1. "run-out" as angle of the face-grain with relation to the edges of the board along its length. I cut areas of run-out off a long board; ie the grain runs perfectly parellel to the edges along the entire length of the finished spar. 2. "slope of grain" as the general direction of the longitudinal fibers of the wood. I'm gathering that this term is the "runout" to luthiers. Cause: the twist of the tree as it grew. We are limited to 1:15 on the slope. I grade out any wood in excess of this 1:15 and prefer no slope down the entire length of the board. 3. "vertical grain" as the angle of the annular rings from the face of the board when viewed from the end grain. We consider anything from 45 degrees to 90 degrees to the face to be vertical. My cants are quarter sawn so I get a lot of 90 to 80 degree which is my personal favorite. On the cants that are 60, 50, 45, I run the cant through the mill on an angle to get back to at least 70. I don't know what your limits on vertical are. do you mill from a split face to minimize runout? This would be what is normally looked for in soundboard wood. 1. We also look for VG. Close as possible. 2. Generally I think a limit closer to 1:28 or less would be our target(if you are maintaining 1:15 along 18', I am sure it is likely better than 1:28 along most of the board) . 3. Within 5 degrees of 90 is what we look for, and within 2 degrees or dead on 90 would suit highest grades. Yes, we mill from split wood(wedges split from 24-30" long rounds). It is much easier when you are looking to meet these requirements in a 24" long piece(not 18' boards). Color variation is another thing that is generally important. It would also be important to consider flaws that may be disregarded in aircraft lumber, as even small(solid) pin knots or pitch pockets are issues on soundboards. Grain spacing (even spacing) is desired. Hope that helps a bit. Rich

Page 1 of 1	All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/