wood thicknessing question

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thetyreman

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so I have a piece of 50mm thick wood, that I want to get down to 32mm, should I do it in stages to prevent movement? and if so how much is a safe amount to take off at once per day? how long should I leave it to rest between taking it off? I was thinking of taking off 2 lots of roughly 9mm at a time, I'll be sawing it with a handsaw then planing it and it's english pear wood.

cheers,

Ben.
 
There is never a guarantee that wood will not move when ripped down. Dry is a good help as is quarter sawn. Absolute safest way is do the same to both sides and do it as one job. If you are sure its dry and the growth rings are near to giving you quarter sawn then I would be tempted to save as much of the rest as a usable board.
Regards
John
 
What a quandary! I’ve been in this position a few times. 50mm to 32mm that’s 18mm extra, surely I can rip that off as a usable board rather than waste it as chips!

I would firstly flatten one face then see what the min thickness is at the worst corner. Often I’ve found that 50mm nominal board is suddenly 44mm at best, 2mm for the bandsaw kerf and you may end up with a 12mm thick board.

If the important aspect is the 32mm board rather than any wastage then I’d flatten one face, take an even amount off both sides to leave you with 3-5mm oversize, depending how brave you are. Leave it 3-5days and see what it does. The then take it to size in one or two more steps, but use it in good time once you’re at thickness.

I’ve no idea if this is the correct answer but from my limited experience that’s how I’d approach it.

Fitz.
 
it's pretty much quartersawn which probably helps, I'll work on some other jobs and leave it about 5 days, I've already taken off about 10mm so it's around 40mm right now, I'm making a guitar and there are other jobs to do, maybe I am over worrying?
 

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What a quandary! I’ve been in this position a few times. 50mm to 32mm that’s 18mm extra, surely I can rip that off as a usable board rather than waste it as chips!

I would firstly flatten one face then see what the min thickness is at the worst corner. Often I’ve found that 50mm nominal board is suddenly 44mm at best, 2mm for the bandsaw kerf and you may end up with a 12mm thick board.

If the important aspect is the 32mm board rather than any wastage then I’d flatten one face, take an even amount off both sides to leave you with 3-5mm oversize, depending how brave you are. Leave it 3-5days and see what it does. The then take it to size in one or two more steps, but use it in good time once you’re at thickness.

I’ve no idea if this is the correct answer but from my limited experience that’s how I’d approach it.

Fitz.
If it moves at all in 3 to 5 days I'd leave it another year before trying to make a guitar with it.
Also I'd have thicknessed it first before sawing the shape.
 
jacob it's for a guitar making competition so it has to be completed by the end of november lol will see if it moves.
 
And when you leave it for a few hours or days then leave it on it's edge, so that both surfaces have more or less equal exposure to the air. At least I do that, otherwise they move and bend a lot. Especially thin ones, like 20 mm or less. Maybe even elevate it a bit with some sticks, like you would do it for drying green wood.
 
At that thickness, and so nicely quartersawn, I'd be surprised if it moved much if at all (unless there were unrelieved stresses in the wood, in which case it would probably have moved already). I've successfully resawn 12 mm blanks in half to get fretboards, all quartersawn of course. Before I understood this I tried it with wood with curve in the end grain - not recommended!

I reckon if you take 4mm off each side, assuming it hasn't moved so far, you'd be down to your 32mm and pretty likely not to have problems. Maybe just take 3mm per side, leaving the last 1mm each side for surface planing etc.
 
it turns out this pear wood is incredibly stable, it hasn't moved even a fraction of a millimetre after taking out loads of it, can see why it was used by pattern makers in the past.
 

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