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Thread: Wood Movement
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3rd April 2014, 05:53 PM #16
I agree,
just nice to avoid stats that only cloud ones thoughts, and accumulate info that can be applied.
I understand it be hard to dump on stats from published books like Bootle(be like the bible to some woodworkers), especially after all the incredible effort put in, but I think personal experiments would be more useful. Because it be directly applicable to your climate and timbers you use.
I've attached a picture of a page from a book I read years ago, but haven't had the chance to do myself. The books called ' The best tips from 25years of fine woodworking…workshop methods of work' .
If I was interested in setting up joinery or cabinetmakers shop with access to the offcuts from a frequently used panel saw, I'd have a wall space filled with end grain strips like this. But have the strips attached to a large grid (line every 2mm or something similar) . Everytime a new timber type is used I'd attach a new strip(not much effort). And simply take notes on where the ends of strips are as the weather changes.
Could literally watch the movement from day to day. See how one moves more than the other. Notice the interesting exceptions to the rules etc. Be able to foresee how things will change in your work when the sun comes out etc etc.
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3rd April 2014, 06:32 PM #17... and this too shall pass away ...
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I made up such a gauge recently. It works, within limits. I used two pieces of timber. One was more dense than the other. Although they are both the same species, this demonstrates the variation that exists within a single species. I love my Bootle, but it is disappointing that he reports a single figure rather than an average and standard deviation so we get a feel for the variation that exists within a species. A search of the web shows that some documents do.
I think both you and Ian are right. The available data gives us trends and general rules which can be a useful guide but which are never absolute. After that it is necessary for us to apply experience and to understand local conditions.
One good example of this is table tops. I personally avoid timber that has high movement for tables (data) and try to be careful selecting boards for the top (experience). We can never stop the top from moving, but in this way the cupping of individual boards might be minimised. Quarter cut timber is best to avoid movement, but sometimes we are looking for a pretty grain pattern, which eliminates quarter cut from the equation.
Cheerio!
John
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3rd April 2014, 07:36 PM #18
Jake, I vaguely remember seeing a hygrometer that used wood movement to drive a pointer in FWW, years & years back, but the one you posted doesn't ring a bell. As I remember it, the one I'm thinking of was a bit more compact, but I've learnt not to rely too heavily on my memory. However, it's a great idea, and maybe 3 or 4 of these with different woods ranging in density from Ironbark to something Balsa-like would show both wood movement & the amount different woods move.
Wonder if I can find a bit of spare wall space in the shed......?
Cheers,IW
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4th April 2014, 08:33 AM #19
yes. I'm glad someone else has said that.
In my huuuuumble opinion…..
If the timber doesn't have pleasing fleck (or whatever you want to call it) when quarter sawn due to strong medullary rays, THEN it looks far better flat sawn.
I've got pep talked by, it feels like, a hundred older, wiser souls, that imply that I don't know what I'm doing when I get my timber flat sawn. Instead they say…
' must make the most of the tree. Must quarter saw the timber !…because its better to have quality instead of a quantity of poor timber…because….you owe it to a tree thats been growing 100 years or whatever.. you foolish dickhead young kid ' . They'll come to your door to tell you. And theres nothing else to say but 'yes, your right' to end the conversation as soon as possible.
But the impetuousness of human behaviour doesn't seem to all die young….because there doesn't seem to be any consideration on why I want it flat sawn.
With windsor chairs most of your parts are turned. So for those parts it doesn't matter, because after turning you can orientate how you like.
The Seat of a windsor chair isn't turned. If the timber your using has strong medullary rays, then shore it can look great in the seat (even though you maybe risking it looking too busy), but with a through sawn log you'll get a quarter sawn piece at the centre. So I try and get the miller to thicken up the middle cut. So you can get your quarter sawn piece for the seat still even though the whole logs through sawn.
If the timber hasn't got strong medullary rays, then the seat looks best when its through sawn (like your saying) particularly imo, when the bark side of board is up because when you carve out the seat you tend to get this beautiful array of symmetric circles. If it was quarter sawn (without medullary) its boring as bat . The rings aren't really seen.
And to top things off, if you do have a part, thats wide and thin, like used mostly in cabinetmaking, thats quarter sawn, showing off beautiful fleck, that you want to bend and put in the chair, its often of no use because the medullary rays want to pop (can see that in Ians pic of the river oak log above somewhere. Where failure tends to occur right on the medullary rays)
So flat sawn is smart for windsor chairs. Easier to do too. (imo)
When I was growing up I was the first kid to say 'sir'. Utter respect for my elders. Now its difficult. Especially when its clear that a lot of the elders, due to their experience, sense your a young fool, and try to make a buck of you. Selling you poor timber that no one else wants etc etc.
But I love you guys ! Especially you guys with lots of money that might buy my chairs ! …..love you.
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4th April 2014, 11:59 AM #20Jim
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"yes, you're right".
Surely two words would have the same effect but quicker.Cheers,
Jim
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4th April 2014, 05:56 PM #21
yeh, and the next day get approached by a teenage bloke,covered in acne, built like a brick house, who I've never met before (of course) come right up to me and jab his finger on my chest with…..
grrrrrr……. My GRANDDAD HAS BEEN IN THE TIMBER INDUSTRY FOR 50 YEARS. IF HE COMES ONTO YOUR PROPERTY AND TELLS YOU TO QUARTERPLANE YOUR TIMBER….YOU QUARTERPLANE IT. GET IT !
ok ok…don't hit me. (because the only way to defend myself against YOU is to hit you over the head with this bit of quarter planed timber) you powerful man you.
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4th April 2014, 07:59 PM #22Jim
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5th April 2014, 03:14 AM #23... and this too shall pass away ...
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Truly we see some madness.
We all know quarter-sawn timber moves less, but if I want to see the lovely swirling red patterns in that nice piece of NG rosewood, I am not going to quarter-saw the darned thing and get nothing more than the radial stripe and perhaps some nice flecking that can't be seen from across the room..
Currently what occupies my mind more that the degree of tangential or radial movement is the likelihood of the individual boards to cup in a largish panel. I got some lovely boards over 300 mm wide a few years ago and was thinking that they would reduce the number of joins in a panel. Not so. I lightly planed both sides (so I could see the grain) , cut them to length and popped them back in the rack for a few weeks. They wanted to cup by enough to be obvious, so it was necessary to rip those wide boards in half and rotate every second board to get a top that would stay reasonably flat. However, for that job this was still better than seeing the radial stripes only.
Have fun!
John
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5th April 2014, 09:11 AM #24
Yep, there are definitely times when you have to break "The Rules". There is no way in the world I was going to cut this crotch of cedar up other than split it for a book-match!
Sideboard doors.jpg
As it was, I was a bit impatient, thought I'd given it enough time to equilibrate, and sawed it for the book-match. It was too soon. Even though I expected the wild grain would cause me some problems, I wasn't prepared for how much it wriggled & squirmed into a twisted, hill & dale mess.
After kicking myself black & blue, and letting the sawn pieces rest for a much more sensible interval, I went at it with planes & care & managed to preserve a pretty good match, despite having to plane off several mm of wood from some parts. But there was no way such wild-grained wood was going to stay flat without some help, so I took my cue from some of the old cedar pieces I've seen, & made the panels as thin as I thought I could get away with (about 1/2" thick), on what are fairly wide boards. As we've been discussing, less dense woods move less, and also develop less power, & the thinner the panel, the less power it can develop, so I hoped the door frame would be able to keep things under control. Either my reasoning was right, or by plain good luck, it's been ok so far. I noticed it is 10 years since I took that pic, and both panels are still nicely flat & sound....
Cheers,IW
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5th April 2014, 11:45 AM #25... and this too shall pass away ...
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5th April 2014, 07:35 PM #26
John, the panel sits in a rebate in the frame (cut from the front) and is held in by the beading. I've studied a few oldies, and some appear to have been done this way, so I chose to copy that. Others don't bother with a rebate, the decorative beading retains the panel at the front, and a plain bead is tacked in at the back of the panel. The beads inside the door are often pretty rough, it's only on exceptional pieces that I've seen the same care taken with the interior out-of-sight parts as the more visible bits. Time was money back then, too!
Cheers,IW