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Grain Count For Brace Wood
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=49628		 Page 1 of 1
Author:  Fasterthanlight [ Fri Aug 11, 2017 7:28 am ]
Post subject:  Grain Count For Brace Wood
Hi Folks

What is the recommended grain count per inch for bracewood? I have some Euro Spruce where the grain looks a little on the wide side.

I guess its different per species?

Any ball park figures would be great.

FTL

Image
Author:  Colin North [ Fri Aug 11, 2017 8:25 am ]
Post subject:  Re: Grain Count For Brace Wood
I don't think grain count makes much difference, apart from appearance which doesn't count for much on braces.
Weight and stiffness is what counts, and it's quite easily measured.
Author:  Fasterthanlight [ Fri Aug 11, 2017 9:04 am ]
Post subject:  Re: Grain Count For Brace Wood
Any formula for that?

FTL
Author:  jfmckenna [ Fri Aug 11, 2017 10:50 am ]
Post subject:  Re: Grain Count For Brace Wood
You might even be surprised to know that orientating the annular rings (grain) parallel to the top is actually stiffer then perpendicular.

Annular ring count isn't important as Colin mentioned. You can measure stiffness by doing deflection testing measuring the dimensions of the brace and pressure of deflection and of course weigh it with a scale.

Here's a long complicated article for ya :)

http://ukuleles.com/?page_id=579
Author:  Imbler [ Fri Aug 11, 2017 5:39 pm ]
Post subject:  Re: Grain Count For Brace Wood
Very true on stiffness. I give up that benefit though and still orient with vertical grain because of ease of carving, and my gut feeling that they are more resistant to cracking/splitting with the grain vertical.

jfmckenna wrote:
You might even be surprised to know that orientating the annular rings (grain) parallel to the top is actually stiffer then perpendicular.

Annular ring count isn't important as Colin mentioned. You can measure stiffness by doing deflection testing measuring the dimensions of the brace and pressure of deflection and of course weigh it with a scale.

Here's a long complicated article for ya :)

http://ukuleles.com/?page_id=579
Author:  Joe Beaver [ Fri Aug 11, 2017 7:15 pm ]
Post subject:  Re: Grain Count For Brace Wood
I agree with Gary, it would be nice to have a standardized test for brace deflection. Then we could talk apples to apples.

As far as grain orientation in braces, I just don't see much difference except maybe a little in expansion/contraction for humidity changes. (seems to me flat sawn braces will deflect slightly less than quarter sawn, but I use CF in my braces so it probably makes no difference.)
Author:  jfmckenna [ Fri Aug 11, 2017 8:10 pm ]
Post subject:  Re: Grain Count For Brace Wood
Imbler wrote:
Very true on stiffness. I give up that benefit though and still orient with vertical grain because of ease of carving, and my gut feeling that they are more resistant to cracking/splitting with the grain vertical.

jfmckenna wrote:
You might even be surprised to know that orientating the annular rings (grain) parallel to the top is actually stiffer then perpendicular.

Annular ring count isn't important as Colin mentioned. You can measure stiffness by doing deflection testing measuring the dimensions of the brace and pressure of deflection and of course weigh it with a scale.

Here's a long complicated article for ya :)

http://ukuleles.com/?page_id=579

Yeah kind of like the one piece VS two piece scarf joint neck argument. The one piece neck has a lot of run out in the angled head stock. Of course a flat sawn brace has a better gluing surface :)
Author:  Imbler [ Fri Aug 11, 2017 8:16 pm ]
Post subject:  Re: Grain Count For Brace Wood
jfmckenna wrote:
Imbler wrote:
Very true on stiffness. I give up that benefit though and still orient with vertical grain because of ease of carving, and my gut feeling that they are more resistant to cracking/splitting with the grain vertical.

jfmckenna wrote:
You might even be surprised to know that orientating the annular rings (grain) parallel to the top is actually stiffer then perpendicular.

Annular ring count isn't important as Colin mentioned. You can measure stiffness by doing deflection testing measuring the dimensions of the brace and pressure of deflection and of course weigh it with a scale.

Here's a long complicated article for ya :)

http://ukuleles.com/?page_id=579

Yeah kind of like the one piece VS two piece scarf joint neck argument. The one piece neck has a lot of run out in the angled head stock. Of course a flat sawn brace has a better gluing surface :)


Ha! Excellent point about the gluing surface. It's all about trade-offs, your neck description is a great example.
Author:  rlrhett [ Fri Aug 11, 2017 10:24 pm ]
Post subject:  Re: Grain Count For Brace Wood
Imbler wrote:
Very true on stiffness. I give up that benefit though and still orient with vertical grain because of ease of carving, and my gut feeling that they are more resistant to cracking/splitting with the grain vertical.


Yeah, I thought I was being clever putting in flat sawn braces. What a PITA to carve. Never again.
Author:  Fasterthanlight [ Sat Aug 12, 2017 2:43 am ]
Post subject:  Re: Grain Count For Brace Wood
Great discussion guys... thanks for the tips.

G.
Author:  Colin North [ Sat Aug 12, 2017 4:00 am ]
Post subject:  Re: Grain Count For Brace Wood
You can easily compare stiffness by taking 2 braces same dimensions and tapping them or dropping them on the bench - stiffer one rings at a higher pitch.
Or you could do a tap test to get absolute measurement of MoE from dimensions and vibrational frequency (Gore Book)
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