Quick Question about rough sawn timber

[wizer]

Hey,

When buying rough sawn timber for home planing (powered) is there a general rule of thumb with regards to how much is planed off?

What I mean is, I am sketching something up and want to work around timber sizes in my design.

and to make it even clearer, if I buy 175mm thick beech, roughly what size will it be planed?

Cheers

 

[DaveL]

Hi WiZeR,

This is a bit along the lines of how long is a piece of string. :roll:

If the sawn board is perfectly flat, NO bow, twist or wind and the saw was sharp then you might only remove 1/4" and you have a nicely prepared board to use. But all of the above may not be true and the board could end up as a pile of shavings and you are left looking for another. :shock:

The selection of your sawn timber is very important, particularly if you need long and wide boards. The shorter and narrower the final board has to be the easier it is to get it out of you sawn board.

I am not trying to put you off but I have some cherry in the shop bought for a desktop that will never be a desktop, its being used for all sorts of things that do not need long, wide boards. :evil:

 

[wizer]

cheers dave, I'll err on the side of caution.

 

[Sgian Dubh]

Allow about 6 mm for most specifying, e.g., 18 mm will generally come out of 25 mm thick stuff. If the you are making a long table top that needs to finish at 18 mm you may well need to buy in 32 mm (1-1/2") stuff.

If boards are wide and very warped, cupped or bowed you may need to cut the material into shorter or narrower lengths to achieve the requisite thickness or width. Slainte.

 

[AndyBoyd]

I have tried on too many occasions to be too optimistic as to the amount of planing rough sawn lumber needs. Now I alwys buy 40% more vol;emn than I need. (even this mark sometimes fails) :roll:
Don't forget some species even warp a little after palning sas the now released stresses come out. So you need top plane them again!! Ask Houtslager about his yew bookcase project.

 

[RogerS]

WiZeR - are you talking soft or hardwood?

Only reason for asking is that I made the mistake of getting some rough softwood. I didn't realise it at the time but much of this stuff is (according to the thread I started on the topic some time ago) grown so fast that the quality is useless for planing. I started off with some 4 x 3 and ended up with a floor full of shavings and nothing left on the bench! I never go down that route any more.

 

[jasonB]

I assume you meant to say 175mm wide not thick :?

As the others have said if the boards are straight then 3mm off each surface is a general rule of thumb.

The last lot of beech that I bought was calibrated and only needed one pass off each side to get a decent planned surface so check with the supplier what you will actually be getting.

Jason

 

[wizer]

thanks guys, It was actually beech that I had in mind. I have now decided to buy planed timber as it didnt work out economical to rent the P/T for the day.