<Spock>Fascinating</Spock>
<McCoy>It's a joint, Jim, but not as we know it</McCoy>
Hoping Peter Millard joins this discussion soon, as I know he has tried various KD systems, including the Festool one for Domino slots and, IIRC, the Lamello Zeta ones too.
I haven't yet used either. There's one issue that would concern me: the keyhole approach.
I'd use KD fittings if I needed to assemble
in situ but wanted to do everything but that somewhere else. They make a lot of sense. The Lamello and Festool systems grip and pull up the joint face-to-face (the force is perpendicular to he mating surfaces), and it's the connectors that provide all the strength.
With this one however, you slide the two mating surfaces, and to some extent rely on friction to keep everything in place.
- If your finish makes the surfaces slippery, or you are using MFC or MF MDF, or MF ply, that might be a problem.
- If you have a paint finish, banging on the edge, even with a block, might damage your finish.
Whatever the sales "puff" says, the joint strength can only be a fraction of the unmolested material (ply in the videos). I couldn't say whether other systems might be stronger, but the carcases evidently need to be in 18mm in order for the fixings to have sufficient strength. So you might end up with construction that is mostly a lot heavier than needs be otherwise.
You also need both the router plunge depth and the drill depth for the end of the mushroom to be spot on or the joint either won't go together or it will be loose. And it's only "adjustable" once it's apart.
Both the other two systems, to an extent, give you adjustable tightness of the joint. This works the other way - the initial fit will be snug, because you are compressing the wood fibres. Any movement might loosen it, but you most probably won't be able to tighten it easily, or knock the joint back apart again without damage, because you have compressed the wood fibres and the head of the mushroom is sitting in an indent inside the second piece of the joint.
It's a neat idea, but even if cost were no object, I'd struggle to find an application, given I have a Domino.
The Domino KD fittings are expensive, but you can get the starter kit for 85 quid less than the Peanut system: the KV-SYS D8, for the DF500 is 315 quid at Axminster presently. The kit to do about 64 DF700 joints, SV-SYS D14, is roughly 416, but it's not an exact equivalent to the DF500 kit, as it seems not to have the extra tooling for drilling and adjusting the fittings.
E.
PS: With 18mm ply (even 12mm) you could even sink carefully-piloted wood screws into the edge, with low expectation of splitting. Might be
slightly cheaper too ;-).
£400 for a jig!” comments and brings the price of entry way, way down, which should make it much more interesting to occasional users.
♂ Also, speaking as a fellow Domino and Zeta owner, if you can’t see the benefits of this system vs the shortcomings of what you already have - and as fine as they are, all tools have shortcomings - then I don’t think you’re really being open-minded.
