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Sawn timber sizes

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Sawn timber sizes

Postby RogerS » 17 Mar 2018, 13:25

I really should know the answer to this but I don't.

Take a piece of sawn timber...quoted at 50mm x 100mm ..is it really that size ? What's the largest cross-sectional area that could be planed out of such a piece ? If it really was 50mm x 100mm then I guess I'd expect to get 46mm x 96mm maybe ? But if it was actually, say, 48mm x 98mm then it wouldn't.

I see that Travis Perkins offer a piece 47mm x 50mm so what's all that about ?
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Re: Sawn timber sizes

Postby Jimmy Mack » 17 Mar 2018, 13:42

RogerS wrote:I really should know the answer to this but I don't.

Take a piece of sawn timber...quoted at 50mm x 100mm ..is it really that size ? What's the largest cross-sectional area that could be planed out of such a piece ? If it really was 50mm x 100mm then I guess I'd expect to get 46mm x 96mm maybe ? But if it was actually, say, 48mm x 98mm then it wouldn't.

I see that Travis Perkins offer a piece 47mm x 50mm so what's all that about ?
**** Quoted: 50x100mm for sawn****



*SAWN*

50x100 nominal (but actual size supplied as sawn)

So you can prepare to 44x94 (approx )


*PAR/ PSE*

50x100 will be it's nominal size opposed to actual actual size 44x94, where the yard are preparing for you.




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Last edited by Jimmy Mack on 17 Mar 2018, 13:47, edited 1 time in total.
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Re: Sawn timber sizes

Postby Jimmy Mack » 17 Mar 2018, 13:46

Depending on the yard and quality of board, I'd allow for 5-6mm PAR.

It's not unusual for sawn boards to be over nominal (50x100) if you can have a good fish through the sawn pack.

That Travis size is odd, I agree.

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Re: Sawn timber sizes

Postby Mark A » 17 Mar 2018, 14:24

Around here merchants categorise both rough sawn timber and regularised timber (smooth sides, rounded edges) sawn, which has caught me out a few times.
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Re: Sawn timber sizes

Postby RogerS » 17 Mar 2018, 15:51

Thanks guys.

I wonder if there is a third scheme, namely constructional timber like CLS, and that is the Travis size ?
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Re: Sawn timber sizes

Postby Doug » 17 Mar 2018, 17:10

I think it has to do with where the sawn timber is sourced. The sawn redwood I’ve been buying is a good 2 x 9” some nearly an 1/8” over but all at least 1/16” over 2” so on the straight lengths I’d have probably got close to 50mm.

Don’t know if it’s just my merchants but sawn is always sold there in inches but PAR in mm, possibly as a lot of the sawn timber is coming from America & is planed up over here.
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Re: Sawn timber sizes

Postby Mike G » 17 Mar 2018, 18:06

RogerS wrote:I really should know the answer to this but I don't.

Take a piece of sawn timber...quoted at 50mm x 100mm ..is it really that size ? What's the largest cross-sectional area that could be planed out of such a piece ? If it really was 50mm x 100mm then I guess I'd expect to get 46mm x 96mm maybe ? But if it was actually, say, 48mm x 98mm then it wouldn't.

I see that Travis Perkins offer a piece 47mm x 50mm so what's all that about ?


I don't think many places sell 100x50 any more, as I can't find anything but CLS timber these days. You can generally expect these to be 5mm under the old sawn sizes, but they are semi-planed, and with the edges off. So the equivalent is approx 95x45. The one thing you can be certain of with CLS timber is that it will be dimensionally accurate.

47x50 is re-sawn from 100x50, so is obviously minus the kerf.
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