Thread: Best local timbers for handling hammers?

Originally Posted by Bushmiller

The latest edition of Australian Wood Review (No.84) contains an article by former CSIRO scientist Jugo Illic on timbers suitable for tool handles.

Regards
Paul

Are you going to give us a summary?

Originally Posted by DSEL74

Are you going to give us a summary?

If nobody else has jumped in with a summary, I will see what I can do tomorrow evening. I don't have my copy of the mag with me.

Regards
Paul

Yes please!

Ok, I will try to give a brief summary of the two page article in the latest AWR on timbers suitable for tool handles. You have to be aware that it is a review as clearly there are copyright laws that prevent unauthorised reproduction.

Professor Ilic emphasises a couple of points in particular. Firstly, that a high shock resistance is essential in any tool that is struck or swung. He cites the example of an axe where some of the energy goes into the chip, but absorbtion by the handle within the eye causes mechanical degradation too. The ability to achieve satisfactory absorbtion is provided primarily by the timber's toughness. There is also the side issue of handle abuse (more so in the case of miss-hits with an axe than your hammer for example). Toughness also exhibits a greater ability to withstand this.

Toughness is not hardness, although the tougher timbers will be relatively hard too. A good example of this is Gidgee, which although extremely hard ( scored 10+) was not tough (5+).

A table of suitable species was drawn up with American Hickory featuring at the top and as the comparitor (Toughness 10+, Average density 8+). The following Australian timbers also scored 10+ for toughness arguably putting them on an equal footing with Hickory.

Wirewood (Acradenia frankliniae)
Ironwood (Backhousia myrtifolia)
Grey Handlewood (Aphananthe philipinensis)
Black Wattle (Acacia mollissima)
Brown mallet (Eucalyptus astringens)


The following also scored well:

Ironbark Grey (Eucalyptus paniculata) 10
Hickory wattle (Acacia penninervis) 9+
Spotted Gum (Corymbia maculata) 9
Southern Blue Gum (Eucalyptus Globulus) 9
Karri (Eucalyptus diversicolor) 8+
Crows Ash (Flindersia australis) 8

Others of interest :

Mountain Ash (Eucalyptus regnans) 7+
Blackwood (Acacia melanoxylon) 7
Jarrah (Eucalyptus marginata) 6

Another point Professor Ilic makes is that grading of these species is very important. Straight grain free of defects can significantly improve a timbers performance or conversely de-rate it.

It is in fact why Hickory had in past times become so revered as the timber grading was strict. I have heard that modern Hickory is not the timber it once used to be, but that is probably anecdotal and also applies to almost every other timber too.

The article also points out that Spotted Gum is the only Australian species available in sufficient quantities for commercial production.

I have deliberately kept in the latin names, at the risk of boring your timber ar*es off, for a good reason. Take Ironbark and Black Wattle, which both have a number of species attributed to them: Dai Sensei put up a post in recent time that identified at least twenty different trees that were called "Black Wattle" and the other Ironbarks (Red, Narrow leaf, Broad leaf etc) are unsuitable for handles. This is the impact resistance (Izod test) of Ironbarks (from Keith Bootle's Wood in Australia.)

Grey Ironbark 27 (Janaka)
Red Ironbark 14 (Janaka)
Red Ironbark (broad leaf) 18 (Janaka)
Red Ironbark (Narrow leaf) 13 (Janaka)

If any of you have had to split Ironbark for firewood, you will know that some splits if you look at it fiercely and some will bounce the block splitter back ten feet behind you. I think we know why now.

Interestingly, Hickory scored only 8+ in the density stakes and was beaten on that measure by twelve Australian species, but we all know that Australian hardwoods are legendary .

Lastly there is a reference to substitute timbers (for furniture, bending, musical instruments, boat building, construction timbers,heavy tool handles, chisel and knife handles, sporting equipmentand food safe) that featured in an article (also by Professor Ilic) in Issue No.52 of AWR , but I will leave you to read that one for yourselves or obtain a back copy. You can do this by visiting their website.

I daren't infringe the copyright laws any more and I am expecting the AWR heavies to bang on my door at any moment. I am going to install impact resistant doors all around the house. Grey Ironbark I think would be the go or Spotted Gum, for which I have a prejudice (from the foregoing )

www.woodreview.com.au

Really you should all get a copy of the latest AWR as it has two articles by Forum members. I'm sure you will recognise them:

Plane making from a kit by Ian Wilkie (roadtest of the Veritas wooden plane hardware kit)

Tools for Inlay by Phil Perkins (review of Lie Nielsen and Veritas systems for cutting inlay stringing)




I hope this helps you.

Regards
Paul

Thanks Paul.

Thanks Paul,

I'm going to pick up a copy of that issue of AWR.. so, when they come knocking... you can tell the heavies, that you are actually increasing their sales...

Ray

The selection of wood(s) for hammer handles is based on the mechanical properties of the wood anatomy.
If you can't get past that understanding of the vast difference in anatomy and utilize that information,
you might as well use anything.
In North America, Ash (Fraxinus) and Hickory (Carya) are used for dang good reasons
which have everything to do with quality and nothing to do with quantity.
Question: what have you got in Australia with a similar anatomy and similar mechanical
properties?
I'll bet that your Spotted Gum bears a strong resemblance in wood anatomy to my top choices up here.

We don't have the strongly seasonal growing conditions that tend to produce strongly ring porous timbers, ie short summers/very cold winters or short monsoon/long dry. As such most of our hardwoods are diffuse porous or weakly ring porous.

Spotted Gum is diffuse porous according to the references google throws up.

Ring porous or diffuse porous is a genetic characteristic of the species.

I would love to see transverse sections of all the woods that Bushmiller
noted in his fantastic summary (many thanks for that.) Would it be possible
to get Prof Ilic, himself, into this?

The other thing you could look into is ordering reprints of the specific article.
Very common & accepted practice in science.

North American woods grown in cool/cold climates have longer fiber than the exact same
species growing in warmer, wetter situations.
Eastern North America experienced a couple of centuries of cold weather, so much so that in fact,
it's still referred to as the "Little Ice Age."
Consequently, the mechanical properties are better than modern woods with shorter fiber.

Originally Posted by Robson Valley

Ring porous or diffuse porous is a genetic characteristic of the species.
.

These terms refer to structural differences arising from the way hardwoods lay down water transporting and load bearing cells. Strongly ring porous hardwoods lay down large porous celled early wood at the start of the growing season and smaller and denser cells at the end of the season giving the characteristic structure of things like Hickory and Oak. Diffuse porous woods, like Spotted gum lay down water transporting and load bearing structures more evenly throughout the year. Although the cross section will typically still show annual growth rings they don't indicate rings of porous and non porous material. As such looking at cross sections of timber might not give a good indication of the physical properties.

[Edit] in lieu of proper references for my little essay here is a really good general summary of the properties of wood. http://www.fao.org/docrep/009/j8289e/j8289e05.htm

Originally Posted by Berlin

Diffuse porous woods, like Spotted gum lay down water transporting and load bearing structures more evenly throughout the year. Although the cross section will typically still show annual growth rings they don't indicate rings of porous and non porous material. As such looking at cross sections of timber might not give a good indication of the physical properties.

[Edit] in lieu of proper references for my little essay here is a really good general summary of the properties of wood. http://www.fao.org/docrep/009/j8289e/j8289e05.htm

Matt

That's a good reference. If I had known what it contained, I would have waited until my brain was at it's best (Could have been a while ) before trying to digest all that. Quite apart from the suitability of timber for tool handles (I was going to say for "tools," but I could see the path that would lead ), I picked up some other points. Please allow me:

"Baseball bat and tool handle manufacturers in the US often set upper limits on rings per inch that they will accept in ring porous woods like ash, and hickory destined for these high strength requiring applications."

That would at least explain the grading aspect I previously mentioned. It also explains why, on paper at least, Spotted Gum presents superior characteristics to Hickory. It has better impact resistance and better modulus of rupture. However the timber grading probably lets it down. I have most figures for SG, but not all categories for Hickory. By the way, there are about five common species of Hickory, but only two of them excel for tool handles (and Pecan is not one of them . )

The following extract sounds like it was written just for Spotted Gum:

"The species most prone to developing large unrelieved internal stresses are high density diffuse porous hardwoods – and this is greatly magnified when these trees grow rapidly, reducing the time during which some stress relief could occur."

I only occasionally nowadays operate a horizontal bandsaw timber mill,(this is for those that don't know and those who may have wondered about my Forum name) but cutting Spotted Gum in the past I have seen the effect of growth stress where as I finished cutting a board 4.5m long I saw the start of the cut had risen (against gravity of course) almost 300mm (that's 1 foot to you RV ). A consequence of that was that I would only cut SG logs of any length if they had a diameter greater than 600mm.

Going back to the growth rings for a moment it is the timber we call Oregon (Douglas Fir) that typifies for me the difference in growth rings because of the high definition between early and late wood.

One last comment (for this post) is that the Australian handle manufacturers make full use of the sap wood on Spotted Gum. This is particularly attractive to the sawmiller as SG sap is up to 40mm thick and maximises the recovery from a log.

Regards
Paul

I thought of you, Paul when I read that about the reaction wood

Boy, you did skim that document if you'd read the second paragraph you'd now that Oregon is an abrupt transition conifer and has nothing to do with the rings in hardwood. tsk tsk, focus Paul

Originally Posted by Berlin

Boy, you did skim that document if you'd read the second paragraph you'd now that Oregon is an abrupt transition conifer and has nothing to do with the rings in hardwood. tsk tsk, focus Paul

Damn! What I need is a clever head like Worzel Gummidge, but missing a crucial piece of evidence is not the worst part: The worst part is I have to go back and read your link again .

I am reminded of something I read somewhere:

"Most books are lucky to get a revision once every five years, errors here are pointed out in twenty minutes!!"

Actually in a pathetic attempt to extricate myself from a black hole, I wasn't suggesting that Oregon has anything to do with hardwood, just pointing out the very obvious distinction between material added to the tree at different times of the year. Neither am I recommending it be used for tool handles .

Something else I should emphasise, but probably isn't necessary, is that these impact resistant timbers are only required for handles that strike or are struck. Clearly they are not required for something such as a marking knife.

Regards
Paul

Conifers, "Oregon" and all the others, simply are not fit for hafting anything but
the very simplest of wood carving tools. Even then, there is a magnificent spectrum of better woods.
Wood anatomy reflects mechanical properties. No hocus-pocus about it.
You all in OZ have a wide selection to select from. We don't.
Emerald Ash Borer will screw over our continent's population of Ash/Fraxinus
within the next decade.
In British Columbia alone, we have 18,000,000 ha standing dead and cracked pine
from the Mountain Pine Beetle devastation of the past 15 years.
Was not worth the chainsaw gas to cut it down.
But
The fuel resource as compressed hyper-dry wood pellets has been wonderful.
I burn those in a Harman PP38+ stove to heat my home for the winters.
No more (I hope!) than 5 tons/10,000lbs per winter.
I know, it sounds like a lot. Ton at a time is no big deal as 50 x 40lb bags.