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Wood Nominal vs Actual Dimensions (Inches and Metric) 1.0

A list of handy dimensions for CAD / CAM work.

  1. jamesdjadams

    jamesdjadams Veteran
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    jamesdjadams submitted a new resource:

    Wood Nominal vs Actual Dimensions (Inches and Metric) - A list of handy dimensions for CAD / CAM work.

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  2. MaryD

    MaryD OpenBuilds Team
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    Bad link - can you update?
     
  3. David the swarfer

    David the swarfer OpenBuilds Team
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    the whole nominal vs actual dimensions is a fresh hell every day. round here, every batch of wood is a slightly different size so what i do is buy the wood then measure it and then do the design using the actual dimensions.
     
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  4. BNMaker

    BNMaker Veteran
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    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 :)
     
  5. BNMaker

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    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.
     
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  6. Gary Caruso

    Gary Caruso OpenBuilds Team
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    2 by 4 is a colloquialism... just like that I had a chance to use colloquialism in a sentence.
     
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  7. jeffmorris

    jeffmorris Veteran
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    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.
     
  8. GrayUK

    GrayUK Openbuilds Team Elder
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    We call it a 4B2. :D
     
  9. BNMaker

    BNMaker Veteran
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    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 ;)
     
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  10. joe williams

    joe williams Veteran
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    ...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 !
     
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  11. BNMaker

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

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