List of International Lumber Sizes Needed
-
Don't know who you met... but I've been in the UK forever and from the late 1960s I've used folding wooden rulers like this with inches on one side and cm/mm on the other... Very useful doing surveys of smaller dimensions, you can also fold its end at 90 degrees and reach it up up to measure smaller horizontal dims beyond your reach etc... No ones survey box is complete without one...
PS: the saw is a labelled 20" one NOT 50cm/500mm etc
PPS: Although the UK went metric years ago I am still bi-dimensional - I will often say to a carpenter that the piece of '4 by 2' should be 3m long etc [=100x50/3m], or the bearer will need to be around 4 long, 50 thick and about 6" deep ! = 4m/50x150mm:?
It's also complicated by the fact that in the UK older people are Imperial, younger ones learnt cm/m, the building industry is mm/m with architects works mostly in mm so I'll dimension something as 4000 [no units] but say it's 4m !, conversely land-surveyors use m - so they'll say it's 50 means 50m when I'm thinking 50mm... but layman is expecting 50cm (~20") !!!
Not to mention that most UK door-leaves readily available 'off-the-shelf' from a builder's merchant are described in metric but are really still imperial e.g. a 762mm door is actually a 2'6" door - this is because there is so much old housing stock where the door-leaves were/are in imperial sizes that house builders still use them in their new work - although most architects now specify metric doors in new commercial work [made to special order] even then it's confusing - a nominal 900mm wise door-set fits in a hole that is 4nr 215mm bricks [or 440mm concrete blocks] wide with 10mm joints so with the extra joint that's actually 910mm, the standard metric leaf is 826mm wide so with say ~2mm tolerance/gap at each side that's a 830mm hole needed for the door-leaf, so 910-830=80mm that's left over for the two frames/linings - luckily the standard timber linings are ~32/35mm each so that leaves ~5/8mm tolerance per side to pack/adjust the frame as masonry is only accurate to +/-10mm !!!
Also we always measure/sign UK road distances in miles/yards [ironically our only 'land-neighbour' Ireland went metric a while ago and now use km, but for along time they had kms on signs in the countryside but kept miles on signs in Dublin - both signed without units after them leading to some confusion] - we also have UK speedometers in both mph/kph but all speed-limit signs are in mpg.
We often think of our own weight in stones (1st=14lbs) and always buy beer in pints/halves - and even though petrol/gas' is now sold by the litre [~£1.10/l !!!!!], most people still talk of the 'mpg' for their cars' consumption [=miles per gallon]. -
-
Technologists or people that have never worked in a trade, or on a job site invariably get caught up in the precision of a line, that has no thickness, that only a computer can generate. In the old days the width of pencil line on a scaled drawing could in reality be 1/2" thick depending on the scale of the drawing.
Now the question! Does anyone really care if the wall you are drawing is really 4"wide or 3.5"wide?
-
-
@tig said:
PS: the saw is a labelled 20" one NOT 50cm/500mm etc
Look closely. In much smaller letters it's 500mm.
And thank you for the helpful tables.
-
Can someone enlighten me re the British tolerances?
Is British lumber really (nominal +/- tolerance) or do manufacturers stick to (nominal - tolerance)?
Here, for example, 3/4 inch plywood is permitted 1/32 variation. Our 3/4 plywood is always 23/32 thick.
-
Martin, have you looked at the Woodworking userboard? Maybe a post there will make your question more visible to people within the trade?
-
There isn't much more if anything to add.
-
@martinrinehart said:
Here, for example, 3/4 inch plywood is permitted 1/32 variation. Our 3/4 plywood is always 23/32 thick.
well, 23/32 is actually printed on the sheets and then the variation comes into play so 3/4" ply is often 11/16" thick..
(3/4 ply is just a lot easier to communicate than saying/typing/ordering 23/32)
-
This is a humorous thread asking about acceptable variations and tolerances in production of plywood that is "always" 1/32 less than that by what it is commonly refered even though it is stamped 23/32...which is what it "always" is. Perhaps it is tolerances and variation in language or nominclature that is the issue. If this variation is to be coded into a ruby, I am going to be very confused. Would I follow it with a ._s or a ._i ?
If plywood sold at the yard is stamped 23/32 and there is an "acceptable" 1/32 tolerance, but it's always 23/32...why do we call it 3/4" plywood then claim it's a tolerance issue and within spec?
Does 3/4" plywood even exist anymore? -
@mics_54 said:
Does 3/4" plywood even exist anymore?
yeah, i occasionally need 5x10s and my source provides AC grade 5'x10' 3/4 fir ply that's actually 3/4" thick..
bottom line, with standard grade lumber, never assume your lumber package is going to be exactly anything.. onsite adjustments are normal practice.
-
@unknownuser said:
onsite adjustments are normal practice.
Which is exactly the issue. This is why "# comments" in a ruby would exist. Actual dimensions of assemblies such as multiple cabinets or roof structures grow as they are assembled irl requiring adjustments at some point. Bird block lengths between trusses are trimmed as needed to keep trusses on layout.
Assemblies of laminated products from manufactured sheetgoods may have caused the manufacturers to reduce dimensions to accomidate additional layers of adhesives in response to a specific but major market share of their product....or it may have been an attempt to satisfy the needs of imperial and metric standards simultaniously.
Interesting but how is it relevent to ruby programming methods? I hope we don't intend to write .rb files that automatically adjust 3/4==23/32 else if etc.
As a cabinet maker 1/32 only matters sometimes. Uniformity is of more importance. Solid lumber varies considerably from moisture as well as production. Such variations are not controllable large scale given vast climate variations/time/logistics. Solid lumber will be made uniform by the user. Engineered products will not so it makes sense that engineered products need be held to more stringent standards. I feel confident that profit governs the standards.
I'm still not sure how this information would be of relevence in woodworking programming language...I am interested...just ignorant. -
@unknownuser said:
@tomot said:
Now the question! Does anyone really care if the wall you are drawing is really 4"wide or 3.5"wide?
what? of course it matters.. a lot
(unless you're just drawing something purely for illustrative purposes)Within the context of the discussion about lumber sizes, and copying "Quotes out of context". It still does not matter if I draw the exact size of a 2 x 4 precisely 1.5" x 3.5" or be it in metric 38 mm x 89 mm. As a Contractor I don't care, Nor do I care as a Framer. What I do care about; is notes on the working drawings describing size of studs, dimension preferably FOS to FOS. Specifications describing the quality of the lumber, and details of how the Rough Framing is to join with various other manufactured items such as doors and windows, which will help me give a quote for material and labor to the owner. As a Contractor involved in building high end Houses, I'm much more concerned about lumber shrinkage, moisture content which can cause of major problems with various applied finishes.
In addition it should be noted that dressed S4S lumber used in Finish Carpentry has its own sizes. Hence doing a set of shop drawings for a Kitchen Cabinets would be require more exact drawing detail. Where the sizes of the individual pieces would require much greater precision in drafting detail and dimensioning.
-
-
@tomot said:
As a Contractor I don't care, Nor do I care as a Framer. What I do care about; is notes on the working drawings describing size of studs, dimens.....
ah, ok.. i didn't see where you were coming from..
i'm a design/build contractor and i always have a laptop onsite instead of prints and i use it for certain calculations etc where it does matter in it's accuracy.. but, from that, i'll hand out cut/assembly lists/diagrams which are scribbled on scraps etc and i bet if you actually scaled out some of those drawings, a 2x4-8 might really be a 8x10-14.. so yeah, at some point, it doesn't matter how accurately it's drawn and only the numbers written next to them are important..
Advertisement