Miss calculating… is there some easy way?

[conny]

Isn't it potentially quicker and easier just to use Pythagoras and trigonometry? I appreciate that not everyone is comfortable with formulas but there are legions of online calculators.

Most of us only have access to paper as large as A4, it would probably take me longer to sit down and work out a suitable scale and then convert all of the component parts to that scale. And if I make an error, it may be less obvious that I have done so.

That said, regardless of which technique used, it becomes more difficult when working with nominal rather than finished sizes.

I am not a carpenter by trade but have never understood why, when buying timber, you are (often) presented with the nominal, rather than planned sizes. Is there a valid reason for that?

Those nominal and actual sizes bug the hell out of me!

You go looking for a piece of 2" x 4", for example, and bring home a smaller size that doesn't fit!
Make the advertised sizes the finished size. I don't need to know that the piece of wood I want was bigger before it was machined to the size I need. It's common sense that a piece of 2" x 4" PAR is smaller than a piece of rough sawn, but just make the PAR the actual size it needs to be! i.e. 2" x 4" It will save customers a lot of frustration and costs. This in turn will generate more sales.

 

[Gaogier]

I have tried the free versions on things like sketch u, not wanting to spend money on something that I find too hard/complicated to use.

I am not sure if it is me having problem, problem with the service/app or they have dumbed the applications down to get you to order full version

I am just not wanting to spend money I am not happy using.

 

[Deleted member 174758]

Most of us only have access to paper as large as A4, it would probably take me longer to sit down and work out a suitable scale and then convert all of the component parts to that scale. And if I make an error, it may be less obvious that I have done so.

If you do enough of it you might want to consider a scale rule

I am not a carpenter by trade but have never understood why, when buying timber, you are (often) presented with the nominal, rather than planned sizes. Is there a valid reason for that?

Yes. @connie sort of explained it. But the problem with finished sizes is that when converting timber the conversion losses always vary - so one yard might be supplying ex-4 x 2in noml. at 90 x 44mm finished, whilst another might be supplying it at 88 x 45mm finished. It is also not unknown for timber to shrink slightly in extremely dry weather or even swell (in winter), which is all part of the joy of working with a natural material. Oh, and if I need to adjust timber from two different sources I have the choice if specifying "machined exact size" or getting out my circular saw and power planer. Welcome to my world!

 

[Diver Fred]

Yes. @connie sort of explained it. But the problem with finished sizes is that when converting timber the conversion losses always vary - so one yard might be supplying ex-4 x 2in noml. at 90 x 44mm finished, whilst another might be supplying it at 88 x 45mm finished. It is also notbunk own for timber to shrink slightly in extrely dru weather or even swell (on winter), which is all part of the joy of working with a natural material. Oh, and if I need to adjust timber from two different sources I have the choice if specifying "machined exact size" or getting out my circular saw and power planer. Welcome to my world!

Thanks, J&K for an excellent explanation.
In the 60ish years I've been around the woodworking trade (my father was a C&J all his working life) I've only known 1 time when PAR timber of a specified size had to be used. Difficult and expensive. Processing was thought provoking.

 

[robinbanks]

when buying timber, you are (often) presented with the nominal, rather than planned sizes

Because every carpenter knows they're pre rather than post planed sizes. To change it would cause pandemonium

Some things have to be that way because they have been that way!

 

[conny]

Because every carpenter knows they're pre rather than post planed sizes. To change it would cause pandemonium

Some things have to be that way because they have been that way!

But just because something has 'always been done that way', doesn't make it the correct way.

 

[robinbanks]

Sure; I look forward to you succeeding in your mission of getting the timber retail industry to change

 

[John D v2.0]

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I am not a carpenter by trade but have never understood why, when buying timber, you are (often) presented with the nominal, rather than planned sizes. Is there a valid reason for that?

Yes it's a pain and I think that's just the way they create them, same as tarpaulins that are sized before they are stitched. They aren't 100% on how much to plane off, and also it does vary depending whether it's dried out fully or it's been sat in the rain.
Just try understanding BSP threads if you want to be confused, it's something like the outer thread of the measured inner diameter of the pipes that are no longer using that thickness. So basically not directly measurable.

 

[OvertonPlumber]

Yes but a lot of the time the sawmills rip down 8x4 to make 4x2. If you halving something you cannot make it larger.
Also explains where they lose the size the rip blade width on already par timber..

 

[Deleted member 174758]

Yes but a lot of the time the sawmills rip down 8x4 to make 4x2. If you halving something you cannot make it larger.

Depends on the yard. Most of the 4 x 2in framing I've dealt with comes from the mill in packs, ready sawn at 4x 2in (and often with relieved corners). We only get sawn down stuff when there are supply issues, because 8 x 4s would be boxed from the centre for stability, whilst resawn stuff is likely to have pith on the outsides. In any case, a decent yard would be using a band resaw to resize which minimises waste. Maybe small yards are different

 

[robinbanks]

I am not sure if it is me having problem, problem with the service/app or they have dumbed the applications down to get you to order full version

SketchUp's free version is now web based. It still works well apparently, but I always used and preferred the older version that is installed on the desktop. The last locally installed version was SketchUp Make 2017. Try here https://designerhacks.com/skp-download-all/

If you need any help or pointers using it, and you can't find anything useful on YouTube etc, let me know