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Hey all,
Sorry for asking this question, I should know but I can't recall, what is the term for the technical property that describes the strength of timber to resist splitting along the grain. It's doing my head in and Google is defeating me.
Help, it's driving me crazy!
Hi Clinton1
Maybe it is something like this:
'Shear strength parallel to the grain - ability to resist internal slipping of one part upon another along the grain'.
or
'Tensile strength perpendicular to the grain - resistance of wood to forces acting across the grain that tend to split a member'
This came from Mechanical Properties of Wood - Forest Products Laboratory, Chapt 4-3 by Green, Winandy & Kretschmann. there are other related terms that may be more applicable. Available via google as a PDF.
Regards
Twosheds
PS
To put it very simply and is the standard term used in the building industry it's call the F grade, so depending on the use and imposed forces on a timber member an F grade is specified eg: F7 (used for average framing) MGP 10 (multi purpose grade) F14 (moderately heavy loads) F17 (higher loads) F27 (substantial loads)
If you get a copy of AS1684 Australian light framing timber code you will see how the F rating is applied to timber members relevant to their position in a frame and the loads imposed up them
Quote:
Originally Posted by rwbuild
Good Morning Ray
You have got me a little confused on this one.
My understanding of the F-grade system is that it is a measure of the load bearing capacity of a piece of timber in a frame. Basically its stiffness or resistance to bending. It combines several measures. Re-reading AS1684, and I admit that I cannot follow all the technical jargon, does not seem to contradict this view.
Bootles at page 35 defines:
- Shear strength parallel to the grain, and
- Cleavage strength perpendicular to the grain, and
- Tensile strength when a piece of timber is being stretched, and
- Modulus of rupture or bending strength.
Bootles at Table 3.7, page 40, Defines the minimum standards for each F-grade level combining, with minimal measures for each of the following:
- Bending,
- Tension, (for hardwoods and softwoods),
- Shear,
- Compression, and
- Elasticity.
Cheers
Graeme
Your original question relates to only one aspect of the grading system. You are asking for a specific term for your question but after 55 plus yrs in the building industry I have never heard a specific term used or if I did I have forgotten. Suggest you contact TABMA or Forestry commission, failing that, CSIRO timber research division.
The non-word riveability may apply, as in Hand Riven Shakes. :hmm:
As someone who has to split his own firewood most of the year, I can tell you there are quite a few words to describe resistance to splitting along the grain.
Unfortunately, as this is a 'family rated' forum I can't repeat any of 'em.
Still... if, on one winter's arvo, you're driving thru Oberon and see the air turning blue just over the next hill, accompanied by the resounding echoes of an axe bouncing off wood, well... you're probably approaching the nesting place of the Rabid Loon.
If you listen carefully, you may even hear his sporadic call, which normally consists of strings of these words called out randomly and loudly although not necessarily coherently.
(I also recommend not approaching any further, as the Rabid Loon has been known to fling axes & recalcitrant logs with great vigor in random directions.)
:innocent:
I will warn my mate on Duckmaloi Rd to wear ear protection and a hard hat :D
Is "fissile" the word you're after, Clinton?
fissile: adjective
fis·sile | \ ˈfi-səl, ˈfi-ˌsī(-ə)l\
Definition of fissile
1 : capable of or prone to being split or divided in the direction of the grain or along natural planes of cleavage
// fissile wood
//fissile crystals
If it's non-fissile, seems it becomes missile at Ern's place......
:D
Cheers,
Hey all, thanks for the replies.
I thought that the F rating, as per Graeham's post only related to timber in construction uses. But maybe it's shear strength parallel to the grain as per Two Sheds reply.
Thanks RW, I used to know this, but I managed to get a brain injury, and about 20 years of life is pretty much filled with gaps.
Fuzzy and Skew - yes, what's the specific term used to describe splitting ease/difficulty, the scientific term you'd use instead of yelling "you bastard bloody stuff!"
Fissile sound good, I'll hit google up.
I'm thinking that it has to do with % of lignum and structure of ray parenchyma. I call it "interlocked" grain, but I don't think that's it.
When you split wood, you see it, easy splitting wood has long smooth fires on the cut surface running top to bottom of the log section, hard to split is jagged and torn fibres.
This constant "I know this but it's not even on the tip of my tongue" is damn frustrating. Brain injuries are not cool.