Author Topic: Wood database info  (Read 391 times)

0 Members and 1 Guest are viewing this topic.

Offline DC

  • Member
  • Posts: 4769
Wood database info
« on: September 13, 2017, 08:27:01 am »
I've got three pages open for the WDB. Osage, Yew and Dogwood. I know that some of you put quite bit of faith in these numbers and some don't but can we just look at them. Going by the numbers it looks to me like in order performance wise it would be Osage, Dogwood and then Yew. We know that ain't so. Is Yew just an aberration or am I looking at the numbers wrong? Is it possible that the MOE should be a small number?
Vancouver Island

Offline High-Desert

  • Member
  • Posts: 400
Re: Wood database info
« Reply #1 on: September 13, 2017, 08:58:35 am »
MOE is a stress strain ratio. It's a coefficient to describe in which a material deforms before breaking. Lower the number, the more elastic.
Eric

Offline DC

  • Member
  • Posts: 4769
Re: Wood database info
« Reply #2 on: September 13, 2017, 09:23:15 am »
And we want elastic right, or is it just an indication of how thick the finished bow will/should be?
Vancouver Island

Offline willie

  • Member
  • Posts: 1257
Re: Wood database info
« Reply #3 on: September 13, 2017, 09:38:27 am »
i got the three pages open Don

MOE could be best used to predict bow width. Better to think of it as a measure of stiffness rather than elasticity, at least the way we bowyers like to use the term. The qualities that make osage and yew good bowwoods, are not so easily gleaned from most test data.

The numbers in the database are from the forest service labs,  just test results on their samples.

The issues some folks have with the wood datebase website, are conclusions Mr Meier has formed from use of his "bow index", in one of his articles.



« Last Edit: September 13, 2017, 09:50:34 am by willie »

Online PatM

  • Member
  • Posts: 4386
Re: Wood database info
« Reply #4 on: September 13, 2017, 10:21:31 am »
What type of Dogwood?

Offline DC

  • Member
  • Posts: 4769
Re: Wood database info
« Reply #5 on: September 13, 2017, 11:47:12 am »
Mine is Pacific Dog (Cornus nuttallii) which may or may not be similar to Cornus florida.

I have ignored the numbers up til now. Every so often I look and usually wander away muttering to myself so I thought I would ask for a little clarification. Looks like there is none ;D ;D
Vancouver Island

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 6440
  • Keep it flexible
    • Marc's Bows and Arrows
Re: Wood database info
« Reply #6 on: September 15, 2017, 11:20:07 am »
Years ago I tried to correlate the published strength numbers with what I knew about bow wood and gave up trying.  Not long ago I read on this site ww.wood-database.com/ that it was the ratio of MOE to density that made Osage a good bow-wood and that changed my way of thinking, it seems to work.  MOR is still a good indication of a wood's strength in tension
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline Badger

  • Member
  • Posts: 6103
Re: Wood database info
« Reply #7 on: September 15, 2017, 11:44:46 am »
Years ago I tried to correlate the published strength numbers with what I knew about bow wood and gave up trying.  Not long ago I read on this site ww.wood-database.com/ that it was the ratio of MOE to density that made Osage a good bow-wood and that changed my way of thinking, it seems to work.  MOR is still a good indication of a wood's strength in tension

   That is interesting mark, I never could find anything of value to a bow maker. I haven't compared the densities ratio to MOE

Offline SLIMBOB

  • Member
  • Posts: 2750
  • Deplorable Slim
Re: Wood database info
« Reply #8 on: September 16, 2017, 12:53:22 pm »
Ditto here Steve.  I find it all very interesting, but somewhat irrelevant to bow making.  The numbers on black cherry and lots of others suggest things that just don't play out.  The ratio of MOE to density is interesting.  I've tried for years to make sense out of what it is we do and why we do it on these woods.  It always for me comes back around to mostly a sense of feel more than any data.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.