I've done a silly thing...

[GrahamRounce]

I've got 2 1ft squares of walnut & two more of tulipwood, meaning to put them together to make a bigger 2x2 alternating colour table top.
So far so good, but I wasn't thinking when I had the idea that having the grain of the walnut run at right angles to the grain of the tulipwood would look nice.
I have 2 of them glued up, and now it's occurring to me that maybe not having the grains parallel was a Bad Thing! They'll shrink & expand at different rates? And crack? Or at least try to bow the table surface?

Should I scrap those two, make two more, and put them all together grain-parallel this time?

Or doesn't it matter? (Fingers crossed)

Any experience of trying this?

Ta again,

Graham

 

[SVB]

Graham,

I am really a novice at this but a couple of thoughts (sorry, not answers) come to mind:

What is the panel thickness (and does that matter)?
How dry was the timber when jointed?
Were the panels left to equalise to their intended environment before-hand (is there significant changes in centrally heated homes over the seasons)?

Sorry, no answers but some thoughts along the road!

Fingers crossed for you as it sounds a great project.

- One thought, if it came to it, could you re-saw the panels and use them as solid veneer applied to a mdf or ply backing - may give the finish without the worry?!?

Simon.

 

[GrahamRounce]

Good points, Simon!

19mm, and - not that dry, probably, now you mention it! The tulipwood was probably ok, but the walnut had been outside, albeit sheltered, before being in the house for about 4 or 5 days.... Oh....

Think I'd better saw them apart again asap.

Damn. *****.

 

[GrahamRounce]

PS The subject line always makes me think of a letter I saw in the paper once from someone who forgot to include their return name & address with a film they'd sent to Kodak for processing. So they phoned them up, telling the operator "I've done a silly thing". The operator said "Yes, I'll put you through to that department."

 

[matthewwh]

Hi Graham,

If you've still got two edges of each square exposed then the boards shouldn't crack, as they can expand on the fresh air side. Furthermore any tendancy of the boards to cup will be controlled by the adjacent boards being perpendicular.

You may however have a problem with the fact that the joints are taking all the pressure from the different rates of expansion and contraction. A straightforward rub joint or tongue and groove will be weak as all of your joints include endgrain, which is worthless as a glue surface.

In this situation, sliding dovetail joints may be the best way to get the grain appearance that you want and at the same time exploit the natural movement of the timber to work against itself to keep the top flat and the joinery tight.

If you cut the tails on the endgrain edges and the slots in the long grain edges you will get the strongest joint. the last one will either have to be a butt joint or a double female joint with a loose butterfly tenon inserted from the side after the joint is made. As a bonus, if you make the loose tenon from the same material that would usually have formed the tail your table will leave people perplexed as to how you assembled it!

I wouldn't bother with any glue on any of these joints as it won't provide any strength. Better to rout a shallow void in the centre of the underside after it has all gone together and then glue a dutchman in to secure the four pieces at the centre.

 

[Grinding One]

Put them together like a quilt....ever heard of Log Cabin Quilt Blocks?Its kinda like a swirl only square...long,then next piece longer but at right angle to last one,an so on till its big enough and square.

 

[GrahamRounce]

Thanks, Grinding and Matthew. Those long dovetail joints sound perfect - for when I'm a bit more skilled! What do you do, just put a dovetail bit in a table router? Does it really cut that accurately? Mine (actually an upside-down plunge router with guides for the wood) has trouble even cutting a good straight channel in one pass, and I should think with the dovetail bit you can only do one pass?

 

[Grinding One]

Thanks, Grinding and Matthew. Those long dovetail joints sound perfect - for when I'm a bit more skilled! What do you do, just put a dovetail bit in a table router? Does it really cut that accurately? Mine (actually an upside-down plunge router with guides for the wood) has trouble even cutting a good straight channel in one pass, and I should think with the dovetail bit you can only do one pass?

You need a fence with it.Then it will work.

 

[matthewwh]

It's a good idea to remove the bulk of the waste with a straight cutter (preferably spiraled) first and then follow it through with the dovetail bit.

For the tail you set the fence so that you are just nicking the face. Turn the wood around and do the other side, and then gradually sneak up on your finished dimension with repeated passes moving the fence a little closer each time.

 

[GrahamRounce]

"remove the bulk of the waste with a straight cutter...."
Now there's a bright idea...
TY!

 

[Mailman14]

HI, What's a dutchman? (I know, about 5 foot tall, with his finger in a ****...)

For glueing corners underneath - was the statement - is this like a visible biscuit?

IF you try hard enough, male and female dovetails on the adjacent side for all 4 pieces *should* slide together, a bit at a time certainly, but easing them together (friend needed!). I will try this out and see if I can get photo's...

 

[matthewwh]

Exactly! a visible biscuit, I couldn't have put it better myself.

Usually they are used to replace blemishes or unwanted knots in a surface - kind of like a patch. In this instance a piece of ply let in from underneath the table would provide a large long grain to long grain surface for gluing and hold the 4 components together.

 

[Anonymous]

Graham

Wait and see

Although wood moves, I find it doesn't move much at all (if at all) when kept in the same room year after year. Modern centrally heated houses present a much more consistent environment to houses of yesteryear and you'll probably find all is fine

 

[matthewwh]

Here you go:

https://www.ukworkshop.co.uk/forums/viewtopic.php?t=33348

 

[Mailman14]

Matthewwh & GrahamRounce, first, thanks for letting me but in, and second also for sending me a post on the other thread I started (mentioned above).

Silly me, I saw the title, and thought it was about the guy who unclogged his p/t...losing some skin in the process

Hope the pics on teh other thread give some help - apologies for quality of work , but I'm more of a "Butcher", than a "Carpenter"... :roll:

Catch you later,