deep cutting/settling/movement

[fraser]

Hi there,
I've been given a job to make some boxes out of several timbers, 3 in each from walnut, oak, beech, cherry, etc. Basically the finished size is 140 wide by 10mm thick so what i want to do is deep cut a 6x2 board so that i can get three from each. However before when I've tried this I've cut and left it to settle and the wood has cupped too much for me to finish at 10mm. Has anyone got any advice, tips or ways to get round this this time please? Any help appreciated!
Many thanks!

 

[Jacob]

Hi there,
I've been given a job to make some boxes out of several timbers, 3 in each from walnut, oak, beech, cherry, etc. Basically the finished size is 140 wide by 10mm thick so what i want to do is deep cut a 6x2 board so that i can get three from each. However before when I've tried this I've cut and left it to settle and the wood has cupped too much for me to finish at 10mm. Has anyone got any advice, tips or ways to get round this this time please? Any help appreciated!
Many thanks!

Expect to lose at least 3mm from each face when planing, and say 3mm per saw kerf. 3no pieces has 6 faces so total thickness required is (3x10) + (3x6) + (2x3) = 54mm
But in reality this is unlikely to be enough, due to movement and other defects so I'd go for 2 1/2" or 63mm sawn size, minimum.

 

[jeffinfrance]

try leaving it to settle, in stick with something heavy on it.

jeff

 

[fraser]

Thanks very much for the replies. I did use 2 1\2"' last time, then machined it a bit, left it to settle then took it down to finished size. Do I want to leave it after sawing in sticks and if so for how long? Then do I machine in parts, with settling in between, or just in one go and start to work on it straight away?

 

[Einari Rystykaemmen]

Do I want to leave it after sawing in sticks and if so for how long? Then do I machine in parts, with settling in between, or just in one go and start to work on it straight away?

This is depending a lot on moisture- and internal tension of the timber. Timber can also warp, if it has some internal tensions (even if it is absolutely dry).

Personally I resaw timber at least 50% thicker than final thickness and leave it at least a week in warm and dry place to settle down (in sticks). After that I machine it to final dimensions.

Bigger boards => increased settle down time.

If you are going to to make 10 mm thick board, I would resaw it 18 - 20 mm thickness and leave it to settle down for a week or so. Then you have enough wood left if board warps etc. for machining.

 

[fraser]

That's great thank you very much, I will try give that a go. Then I suppose machine it in the one go after it has had a week or so to settle? Also, my workshop is far from warm, if I take it home to where it is heated to settle, then take it back to the workshop to make the boxes, is that not going to cause a problem with movement? They will go back into the warm when they are made however would this change in temperature and moisture in the air etc be a problem when trying to stabalize the timber?
Thanks again

 

[Einari Rystykaemmen]

Then I suppose machine it in the one go after it has had a week or so to settle?

Generally, yes.

Also, my workshop is far from warm, if I take it home to where it is heated to settle, then take it back to the workshop to make the boxes, is that not going to cause a problem with movement? They will go back into the warm when they are made however would this change in temperature and moisture in the air etc be a problem when trying to stabalize the timber?
Thanks again

I have uninsulated and damp workshop myself. In cold (and damp) time of year, I take my timber with me in my house to minimize these problems. You can work with your boards pretty safely several hours sequentially unless your workshop is extremely damp. Normally few hours change of huminidy does not matter. After all, this is not a rocket science. Common sense and little experience will help you through. Don't be afraid to try and fail. Your own (and upcoming) experience is best "teacher". In my opinion, it's best way to learn. :wink: