A few nights ago I was in the middle of constructing an architecture model. I was in the process of gluing the internal walls when, rather frustratingly I glued my thumb and forefinger together with my rather strong super glue. For those of you that make models you will be aware of this nuisance (either that or I have no elegance when making models!). So as I battled trying to free myself while cursing my extra strength glue my thoughts made a natural turn to our timber and how this is adhered.
Traditionally, the way to create a glue edge had been to use a feed through moulder, where the left and right vertical spindles are set with straight knives to produce a flat edge. The problem with this however is that the knife spins around on the block, usually at 6000 rpm. As a result of this the knife hits the timber at about 26ยฐ and scoops out a groove. These grooves can vary widely and at a high feed speed these scoops can be quite wide and often clearly visible.
The second issue raised with traditional methods is that of compression. During the cutting stroke, as the angle changes from 26ยฐ to zero, the compression factor increases through this rotation. This means that the top layer of cells just underneath the knife cut are compressed together resulting in the surface becoming much less porous which means that the glue will not penetrate as well and therefore the strength of the glue line will be compromised.
The way to achieve the perfect glue edge is to use a special saw blade combined with pre-moulding. To do this, there are a number of requisites without which the search for the ultimate glue line will be fruitless. Firstly, the moulder needs to have six heads – two top spindles, two bottom spindles and two sides. The next requisite is that the input material should be accurately finger jointed. Finally, we must assume that all tooling is of very high quality, sharp, and for hardwoods like oak and walnut, carbide tipped at the least, preferably solid carbide.
Set up the first bottom to take off enough material to ensure that after passing this first head it is perfectly flat to the bed, as this creates the first reference point, or datum. Next, the right vertical spindle should be set to remove enough material. The left vertical spindle needs to take enough off the left edge to provide a clean and consistent edge, the same being true of both the top heads, which are there just to clean the timber up and calibrate it, so it requires the least amount of sanding once glued. That takes us to the last bottom, where the real action takes place. The tool here is effectively a saw arbour with two blades, both hogging blades. A special side pressure fence needs to be set up exactly right to hold the timber perfectly still as it guides it in to the special high quality tool. Without this setting at absolutely 90ยฐ, then Staves will not glue together in a flat panel. When working with materials such as oak and walnut, not only must the tooling set up be spot on, but the machine itself should be in perfect condition. Yet even with all this, you still need the skill to set the machine up and operate it.
With worktop demand increasing and customer budgets in mind, getting it right has never been more important. Thankfully for us, we have worked hard to ensure we have all the above. Utilised equipment and manpower means that you get the highest quality product that you deserve.
Curiosity is what gains you knowledge,
what will you learn next?
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