Edge Jointing

[Anonymous]

Although edge jointing to increase board width is pretty common, I've never seen any reference to jointing two boards to increase length. I expect there is a good reason for this but as I have recently been given some nice oak boards which are mostly short, I would like to increase their length by edge jointing. Is this practical? I realise there would be matching problems.
Thanks for any suggestions

 

[Chris Knight]

You can dovetail the ends of boards to join them pretty easily with a Leigh jig or similar. There is a great floor in Leeds Castle which is made of Macassar ebony that is jointed in this fashion (except I guess they didn't have a Leigh jig at the time!)

 

[Dickymint]

Speaking with hours of experience (of reading the wood workers joint book on the throne) could I venture to suggest, as a very green newbie, a scarf joint?

Good luck.

Dicky.

 

[Jorden]

Hi Alpen, you can get end joint router cutters from Trend etc. which put an interlocking saw tooth pattern on the ends of the timber which with glue and pressure does a pretty good job.

The scarf joint is alive and well and still used extensively for edge joints in the wooden aircraft and boat industries. It makes a very strong joint with, in theory no loss of strength over the joint along with no gain in weight. The only down side is the amount of timber the scarf takes up.

 

[Midnight]

Alan.. I believe what you're looking for is a finger joint; allows end grain to end grain laminations, tons of glue surface area and more strength than you can shake a stick at.

I believe Rob's company sells a bench top made from lengths of finger jointed stock, testimony to the strength of the joint...

 

[seaco]

Alan.. I believe what you're looking for is a finger joint; ...

I would second that? also known as a box joint... :wink:

 

[Anonymous]

Thanks for all the replies. I notice that so far nobody has suggested biscuit jointing?

 

[SketchUp Guru]

Alan, biscuits won't make for a good joint in and end grain to end grain situation. The only strength would be from the sides of the biscuit slots and the faces of the biscuits. I don't think you could get enough biscuit slots in there to make the strength.

SEACO, I believe the finger joint being referred to is not a box joint, rather it is like a stack of short scarf joints. It would be cut with a bit like this.

 

[seaco]

Alan, biscuits won't make for a good joint in and end grain to end grain situation. The only strength would be from the sides of the biscuit slots and the faces of the biscuits. I don't think you could get enough biscuit slots in there to make the strength.

SEACO, I believe the finger joint being referred to is not a box joint, rather it is like a stack of short scarf joints. It would be cut with a bit like this.

Sorry my mistake but a box joint would work also...

 

[simuk]

Sometimes use a hooked scarf and wedge joint, to edge joint facia board

Simuk

 

[Derek Cohen (Perth Oz)]

.. and if you do not have a router with relevant bit to make a finger joint, try using a lap joint. This can be dialled in for the strength you require (just make it longer for added strength), and it has the greatest glue area on faces.

Regards from Perth

Derek

 

[Anonymous]

I have aWoodrat so will probably use either finger joints or dovetails.
I can't see any strength advantages in using dovetails in this situation?
Thanks again.

 

[Chris Knight]

Alan, if you are going to use a 'rat to do this, it makes little odds whether you choose to use a straight bit or a dovetail bit, the operation is identical. I guess on balance I would use a straight bit and therefore choose a box joint since any imperfections are less likely to be noticed.