Wood Nominal vs Actual Dimensions (Inches and Metric) 2.0

Bad link - can you update?

 

Same here, Dave. Depends which timber mill it comes from, which timber merchant you buy from.

Luckily, my favourite seller allows me to re-plane to whatever dimension I want - and the yard manager doesn't mind getting my timber from the bottom of the stack (i.e. older and drier), for the cost of a couple of drinks or a pack of smokes

 

It depends which country you are in.

US 4x2 is a very different size to Australian 4x2 or British 4x2 or NZ 4x2 or Malaysian 4x2.

I have some fittings designed for US 4x2, bought from a US retailer, the dimensions are a good 10mm smaller than our dressed 4x2 in NZ.

Our rough-sawn dimensions (saying NZ, although I don't currently live there) are:

Width: 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275 and 300mm. Thickness: 25, 40, 50, 75 and 100mm.

Planed/finished dimensions are significantly smaller: 25 - 20, 40-35, 50-45, 100-90, 75-65...

An NZ 4x2 (100x50) is 90x45 finished size, in the US it's 3.5x1.5 or 88x38 - significantly smaller than the NZ size '4x2'

A UK 4x2 is 95x44 - so marginally different to the NZ one, but still a significant difference to the US size.

Here in the tropical third world, 'officially' finished size 4x2 is 4" x 2" - as is rough sawn - but you are never sure. I carry a pocket-sized sliding gauge whenever I go timber shopping. And it's not only the size which presents problems when designing.

All our timber is tropical hardwood, so building things based on plans from Europe, the US/Canada can be fun. I made a replica of a park bench from the gardens in Melbourne, Australia. It came out really nice - but it weighs about 100kg. I used 6x2 and 4x4 and 8x2, as per the plans, but I could have used 4x1, 8x1 and 6x1 as the damned stuff is so strong. The original was designed for softwood.

For a more internationally-relevant guide to nominal/actual timber sizes, in imperial and metric: forget it. Every country is different, every country has its own standards and what it accepts as deviance from nominal. Best to research your local dimensions and always carry a measuring stick.

 

I thought that a 2x4 piece of wood is really 1-1/2" and 3-1/2" but someone told me that they are not really 1-1/2" and 3-1/2". they may slightly bigger or smaller. If you're remodeling your house, please check the actual sizes of existing wood and new wood.

 

Which just shows how standards change dependent on geo.

4x2 in some places, 2x4 in others.

I buy whichever one, then turn it around to suit the installation

 

...and in some locals metric and imperial are mixed. Lived in Mexico for a while (live in Louisiana, USA now) and when buying metal purlins, they where referred to as 2 x 4 x 6, which means 2 inches wide by 4 inches high by 6 meters long !

 

Yeah, we can get 200*100*12 - 12 feet