What timber to choose for this project?

A pal has asked me to replace some aged timber in the cab of his 1956 Scammell heavy haulage tractor. The timber is 7ft x 4 x 3ins and supports the back of the cab. The weight of the cab has bent the timber at both ends and also broken it at one end I can't tell what timber it is (yet) but think it may be an imported hardwood. Appears to be red in colour. Certainly not oak, ash or beech. Pic can be seen here, sorry about file size:
http://i377.photobucket.com/albums/oo218/1pennyfarthing/Brokenback2-1.jpg My apologies for file size.
The outer ends support the weight of the cab which is not inconsiderable, also subject to a great deal of vibration and temperature change. There is some simple jointing, lap joints, halving and a couple of birdsmouth. I'm inclined to go for oak but would appreciate any other recommendations.
Many thanks, Nick.
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Nick wrote:

Oak and steel don't mix. The tannin in oak corrodes steel.
Ash was used on Morris travellers etc and I think the chassis of Morgan 3 wheelers is made from ash too.
Bob
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Thanks Bob,
ash was, and is, the material of choice of coachmakers and other vehicle body builders for its strength, longevity and propensity for bending easily. The timber I need must not bend easily due to the design of the original construction. I am well aware of the reaction between oak and steel. Fortunately, the main timber I have to replace has only 4 fixings. These can easily be done with non-ferrous items. Any suggestion for a more suitable timber would be welcomed.
Nick.
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Nick wrote:

Somewhere else in the thread there was a reference to railway sleepers. Many UK ones were made from oak but from bitter experience, I know these have lots of embedded grit in them and very quickly wreck cutting tools. However that started me thinking about other woods used for sleeper than you might be able to buy as new wood. One such is Jarrah.
Thrade sources for jarrah here http://www.trada.co.uk/dir/products/517F6888-D47E-452F-9344-29232C043B46/Jarrah
These guys might be able to help with Jarrah or almost certainly new untreated sleepers make from Euro oak http://www.uksleepers.co.uk /
Companies that supply rustic timber framed buildings should be able to do you quality English oak beams.
Good Luck
Bob
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Nick wrote:

Scamell pioneer and explorers were renowned for the way the chassis was designed to flex, presumably to cope with cross axle problems. Apart from brief looks I'm not familiar with them.
I am a bit familiar with unipower and matador tractors ( and milly the 15 tonne lift militant) and I'm sure we cut some ash to restore a matador cab. The chap who converted the matadors as they were demobbed, for timber work, lived locally with his dad. An amazing fitter with one hand missing. The firm's lorry driver could tell who's matador Freddy had built for who many years later if he came across one.
AJH
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Nick wrote:

Hmm. Ash has been mentioned, and its a great light weight springy wood. Not sure its ideal here though.
Ok..no not for this. I'd be looking at a good quality pine frankly. Or spruce. Should be good for another 54 years..
Beech is a really dense hard wood too. Rock maple is also a contender.
have a look here.
http://www.john-boddy-timber.ltd.uk /
Looks like pitch pine is probably what you have there.

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wrote:

Non-durable so not really very suitable here.

ditto
Looks tropical to me but it's a bit hard to tell.
Ipe would be ideal as both very durable and very high bending strength, but I'm not sure how widely available it is in that sort of section (most commonly available as decking). Iroko might be easier to obtain in the size you need, is very durable but lower bending strength (still better than softwood though).
Looks like you could also up the depth by a couple of inches or more to help reduce future sagging, unless that is too inauthentic (and/or add more bracing, which might be more effective vertical but I haven't really thought that through so may be talking out of my fundament there).
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Bolted wrote:

I really don't think so. Quality pine was THE mid 20th century coachbuilding material of choice.
Ash was used for horse drawn, because its light.
But Pine was the material for any sort of tough boring use where the surface finish was not important.
A quick chisel into it and a sniff should tell if its a resiny sort of pine or not. The resiny smell will be musty, but still detectable.
Good pine is streets ahead of most common structural timer in the BM's today, but the specialist suppliers like the John Boddy site I posted, can do it.

Nah. It ain't tropical hardwood. No point in that.
Tropical hardwoods are used for fine high tolerance work, because of the even grain and stability. No one would have used them for a truck frame. FAR too expensive, even then. Teak is the only possible contender but the colour is all wrong..its a red pine of some sort for sure.
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On 12/10/2010 12:54, The Natural Philosopher wrote:

Lathams might be worth a call. They're pretty big in softwoods, including Douglas Fir, Hemlock etc, and are pretty knowledgeable.

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stuart noble wrote:

nice site.
Bookmarked.
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wrote:

Fine high tolerance work like all those harbour walls, railway sleepers, lock gates, etc, you mean?
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Bolted wrote:

None of which use tropical hardwoods.
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wrote:

Right. And the streets of London were never paved with Karri either.
You don't know as much as you think you do, but that seems to be some kind of natural constant.
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Bolted wrote:

I wouldnt knoow.

I think I know more than you think I do.
I've been in vehicles from that period, and repaired them.
Never ever found any hardwood except maybe beech.
Always rough old tough old pine.
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wrote:

They were, OK its Aussie but it was definitely imported. Pall Mall, etc.

I know nothing about truck building but a quick google on truck coachbuilding and timber throws up this: http://www.staddonstimber.co.uk
Anyway the whole question of what it is now is a side-issue - especially as it has failed (albeit way beyond design life). What is it best replaced with was the question as I understood it.
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wrote:

The tropical hardwood of choice for truck frames and lorry decking was Meranti. This is one of the coarse-grained Africans and was imported for this purpose since around 1900 (maybe earlier). It's tough and resists impact damage well, not especially weather resistant (compared to other African tropicals) and it soon looks dull and grey so it was never a decorative wood. You haven't a hope using it for "fine high tolerance work".
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Andy Dingley wrote:

Oh really?
Sorty
http://www.prowood.co.za/merantiwood.htm
Ist a typical isdroco replacement.
Also used as a veneer.
You haven't a hope using it for "fine high

I guess that's why they make widow frames out of it.
Or perhaps you don't know as much as you think you do.
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wrote:

"Malaysian Dark Red Meranti "
Do you see a bit of a difference there? Just because your map still has "The Empire" painted in red doesn't mean that it's the same continent, or the same species.
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Andy Dingley wrote:

Just because you say 'african Mranti' doesn't mean that such a wood exists, or ever has.
I have searched the internet for wood such as you describe, and came up blank. All references to Meranti are of a group of speies that are coarser than, cheaper than, but similar to what is generally termed 'mahogany.
And suitable for machining - typically doors and window frames,. same as Iroco.
There is a reason why tropical woods are useful: The lack of seasons gives a good even grain. The further north or south of the equator the species exists, the more it tends to have a pronounced grain and the faster growing it is, the lighter it is.
So a poplar, is a moderately Northerly species with fast growth. Its Moderately grained and light. Ok grows at similar latitudes: Its moderately grained and heavy as its a slow grower.
The conifers, adapted for sub zero winters, have resinous natures, and very pronounced growth rings: the slower growing pines make very decent wood, if the pronounced grain is not an issue.
They wear badly though..soft wood alternates with hard, so they are never favourite for a fine varnished finish.
With the exception of teak, I cant think of a single tropical wood used *structurally* as opposed to 'for appearance'.
In Europe, you don't import wood expensively when you can grow adequate woods locally.
Pine for serious structure, Oak for final strength, ash for lightness, beech for hardness, and spruce for making houses and bogrolls.
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On Mon, 11 Oct 2010 20:26:25 +0100, "Nick"

I have absolutely no idea, but 10 out of 10 for an interesting and original question. Gems like this make this group a great read :)
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