Is this really true?
e.g., 2 x 8 = Sawn timber 50 x 180 mm = Planed goods, Sweden 45 x 170 mm
An inch, according to me, = 2.54 centimeters
http://sv.wikipedia.org/wiki/Virke
Then if you check http://sv.wikipedia.org/wiki/Tum#Svensk_tum
According to the duodecimal system (verktum) was
* 1 verktum = 1/12 foot = 12 lines = 24.74 mm
According to the decimal system (decimaltum) was
* 1 decimaltum = 1/10 foot = 10 lines = 29.69 mm
Both of these designations are historical, and when today you use inches in certain professional fields, such as in lumberyards or plumbing, you normally refer to an English inch even in Sweden.
8 inches should be approximately 20.32 cm
e.g., 2 x 8 = Sawn timber 50 x 180 mm = Planed goods, Sweden 45 x 170 mm
An inch, according to me, = 2.54 centimeters
http://sv.wikipedia.org/wiki/Virke
Then if you check http://sv.wikipedia.org/wiki/Tum#Svensk_tum
According to the duodecimal system (verktum) was
* 1 verktum = 1/12 foot = 12 lines = 24.74 mm
According to the decimal system (decimaltum) was
* 1 decimaltum = 1/10 foot = 10 lines = 29.69 mm
Both of these designations are historical, and when today you use inches in certain professional fields, such as in lumberyards or plumbing, you normally refer to an English inch even in Sweden.
8 inches should be approximately 20.32 cm
Well... or?
Two inches sawn is 50x50. When planed, about 5 mm is removed, making 2" planed 45x45.
3" - 70 mm (75-5)
4" - 95 mm (100-5)
...
8" - 195 mm (200-5)
Edit:
I do think that the table on Wikipedia seems a bit off. Or maybe I’ve also missed something, and we shouldn't rule that out.
Two inches sawn is 50x50. When planed, about 5 mm is removed, making 2" planed 45x45.
3" - 70 mm (75-5)
4" - 95 mm (100-5)
...
8" - 195 mm (200-5)
Edit:
I do think that the table on Wikipedia seems a bit off. Or maybe I’ve also missed something, and we shouldn't rule that out.
Last edited:
Seems completely weird to me.joflopp said:Edit:
I do think the table on Wikipedia seems odd. Or maybe I've missed something too, and we shouldn't rule that out.
So 8 inches sawn is 195 mm according to you?
8" cut is 8*25.4.
That's how we calculate when we cut...
That's how we calculate when we cut...
I do not know the background to the concept confusion really, but having worked both in sawmills and sales of sawn/planed timber, 8" planed always means 200mm to me, and 8" planed is based on the sawn product and thus always becomes 195mm.
Of course, I mean 200mm. You don't count the last 0.4. At least not in the older sawmills that we have =)
Have raised the issue of errors in the table on the article's discussion page.
One should also be aware that there can be plenty of errors even in printed encyclopedias since, at times, it was somewhat of a sport to include an article about, for example, a fictitious mountain range.
One should also be aware that there can be plenty of errors even in printed encyclopedias since, at times, it was somewhat of a sport to include an article about, for example, a fictitious mountain range.
Some trivia:
In the USA, they have their own measurements for sawn timber.
There, a 2" x 4" often means it has dimensions significantly smaller than the 50 x 100 mm we expect.
I think they account for the saw's kerf in the specified measurement.
I've seen information that it can be 38-40 mm x 88-90 mm in the worst case.
Maybe they subtract a little extra to get a better yield?
In the USA, they have their own measurements for sawn timber.
There, a 2" x 4" often means it has dimensions significantly smaller than the 50 x 100 mm we expect.
I think they account for the saw's kerf in the specified measurement.
I've seen information that it can be 38-40 mm x 88-90 mm in the worst case.
Maybe they subtract a little extra to get a better yield?
Now, there were two different inch measurements, verktum or Swedish inch = 24.74 mm and English inch = 25.4 mm. The so-called "brägårdsmått" referred to the English inch. From the mid-50s, 25.4 mm is internationally considered an inch. But the two different inch measurements might explain why it often rounds to 25 mm.
If I remember correctly, you could buy folding rulers marked with verktum well into the 60s.
Nowadays, sizes are rarely given in inches (except on TV screens); instead, one would say, for instance, 45x95 for a planed stud and 50x100 for a similar sawn one.
If I remember correctly, you could buy folding rulers marked with verktum well into the 60s.
Nowadays, sizes are rarely given in inches (except on TV screens); instead, one would say, for instance, 45x95 for a planed stud and 50x100 for a similar sawn one.
I haven't worn overalls for 10 years, but "tvåtumfyra" is simply jargon for a 45x95 mm stud. No one says "öh hörrö Leffe, langa hit en tvåtumfyra på tre å tretti" and expects to get a stud with the dimension 50.8 x 101.6 mm.
The construction industry's terminology is full of colorful names and illogical expressions. Let's keep it that way, without analyzing too much!!! :-D
The construction industry's terminology is full of colorful names and illogical expressions. Let's keep it that way, without analyzing too much!!! :-D