why I bought a bandsaw
- Thread starter sunnybob
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RogerP
Established Member
It's not surprising as any time you cut a piece of timber like that tension is going to be released. Under weight and in time it may straighten but there's no guarantee it will.
custard
Established Member
He concluded after the video that the cupping was due to case hardening, which suggests less than perfect kilning.
As an aside I'm hearing more and more complaints of poor quality kilning, particularly with Oak, but it runs across all timbers. Yellow patches on Oak, checking, honeycombing, inability to resaw without severe warping, the majority of makers I talk to are reporting it's all on the increase due to boards being rushed through the drying/kilning process.
Some makers are moving to air dried rather than kilned, others are only buying from yards that will guarantee they kilned the boards themselves rather than buying them in ready kilned and will stand by the quality. Furniture makers have always moaned about board quality, but it's now well beyond isolated complaints.
As an aside I'm hearing more and more complaints of poor quality kilning, particularly with Oak, but it runs across all timbers. Yellow patches on Oak, checking, honeycombing, inability to resaw without severe warping, the majority of makers I talk to are reporting it's all on the increase due to boards being rushed through the drying/kilning process.
Some makers are moving to air dried rather than kilned, others are only buying from yards that will guarantee they kilned the boards themselves rather than buying them in ready kilned and will stand by the quality. Furniture makers have always moaned about board quality, but it's now well beyond isolated complaints.
YorkshireMartin
Established Member
How is it best to go about selecting boards for resawing? I've been noticing spring back too and it's put me off trying :/
custard
Established Member
YorkshireMartin":1m66fca0 said:
You can test for case hardening on an offcut , make a trial cut so that the sample looks like a tuning fork, if the prongs move materially in or out resawing isn't going to work. Apart from that, quarter sawn, straight grain, moisture content in equilibrium with your workshop...and cross your fingers!
YorkshireMartin
Established Member
custard":1juxa7qk said:
Do you have a picture of this in practice Gary?
Quarter sawn seems to be so elusive unless it's exotics. Everything I've been able to get thus far has been flat sawn. :/
custard
Established Member
The reason that flat sawn is the most common method of converting timber is because that's what the market generally wants. The market wants the more decorative "cathedral grain" of flat sawn timber, and in particular flat sawn/cathedral grain in the centre but tapering off to rift sawn/quarter sawn at the edges. That means you have the straight, stripey grain at the edges, so it's easier to joint multiple boards together to get wider pieces without jarring clashes of grain patterns.
To get around this you really need to go to the timber yards who have the whole log (sometimes called the boule or the flitch) sawn through and through. You can then get an assortment of different cuts for different purposes. In the south east that means timber yards like English Woodlands, Surrey Timbers, Yandles, Moss & Co, or Tylers, I don't know who the equivalents are in Yorkshire, but they'll be there someplace.
An alternative is to buy really thick flat sawn boards and take slices off the edges which are then effectively quarter sawn, however you usually pay a premium for thicker pieces and you still won't find much over 100mm thick so even then you're only getting boards which are 100mm wide.
I know I keep banging on about getting down in person to decent timber yards and building up a relationship, but for the small independent maker if you can't get precisely the timber you need then you're snookered before you've begun.
To get around this you really need to go to the timber yards who have the whole log (sometimes called the boule or the flitch) sawn through and through. You can then get an assortment of different cuts for different purposes. In the south east that means timber yards like English Woodlands, Surrey Timbers, Yandles, Moss & Co, or Tylers, I don't know who the equivalents are in Yorkshire, but they'll be there someplace.
An alternative is to buy really thick flat sawn boards and take slices off the edges which are then effectively quarter sawn, however you usually pay a premium for thicker pieces and you still won't find much over 100mm thick so even then you're only getting boards which are 100mm wide.
I know I keep banging on about getting down in person to decent timber yards and building up a relationship, but for the small independent maker if you can't get precisely the timber you need then you're snookered before you've begun.
YorkshireMartin
Established Member
custard":yjq7tvrx said:
Thank you dude.
I've already screwed up one timber order this week, but I did learn something in the process. It's really quite complicated to get into for the beginner.
woodbrains
Established Member
Hello,
The guy in the video gave the wrong explaination of the cause of the cupping, though. He seemed to think the inside of the board was dryer than the outside and humidity made the outside wetter which caused the cupping. It is almost always the opposite situation. The board is wetter inside but once cut dries more rapidly than the dryer exterior and shrinks. Now the inside is slightly narrower than the board was originally, there is no option but or the bad to cup inwards. It may be case hardening, or some kilning defect, but I strongly suggest the timber is fine, it just should have been allows to acclimatise to the workshop longer before reading and put I t stick IMMEDIATELY after sawing.
I understand where Custard is coming from, about kilning defects and the benefits of air dried stock, but I do believe the reports of poor kilning stock is largely apocryphal. OK kilning defects do crop up, but improper acclimatisation of timber, not placing re-sawn boards in stick for sufficient time, generally rushing timber to meet unsympathetic client deadlines, and just makers naivete, all contribute to kiln dried timber's bad reputation. (Let's face it, how many 'makers' have just done a 12 month course and think they know it all) In fact, kiln dried timber is often indistinguishable from air dried stuff to most woodworkers.
Mike.
The guy in the video gave the wrong explaination of the cause of the cupping, though. He seemed to think the inside of the board was dryer than the outside and humidity made the outside wetter which caused the cupping. It is almost always the opposite situation. The board is wetter inside but once cut dries more rapidly than the dryer exterior and shrinks. Now the inside is slightly narrower than the board was originally, there is no option but or the bad to cup inwards. It may be case hardening, or some kilning defect, but I strongly suggest the timber is fine, it just should have been allows to acclimatise to the workshop longer before reading and put I t stick IMMEDIATELY after sawing.
I understand where Custard is coming from, about kilning defects and the benefits of air dried stock, but I do believe the reports of poor kilning stock is largely apocryphal. OK kilning defects do crop up, but improper acclimatisation of timber, not placing re-sawn boards in stick for sufficient time, generally rushing timber to meet unsympathetic client deadlines, and just makers naivete, all contribute to kiln dried timber's bad reputation. (Let's face it, how many 'makers' have just done a 12 month course and think they know it all) In fact, kiln dried timber is often indistinguishable from air dried stuff to most woodworkers.
Mike.
Wizard9999
Established Member
custard":26bkwh4o said:
I guess part of the challenge for a weekend warrior like myself is that I buy such a small amount of timber that purchases are not frequent enough to develop at sort of relationship.
Terry.
