I must have missed this thread. I bought a pack of these recently and tested them yesterday.
At present they cost twice as much as Festool 6mm beech Dominos.
As noted above they do not draw parts together but they do have more withdrawal resistance than the standard beech tenons. I estimate they resist withdrawal about 1-1/2 to 4 times as much as the wood tenons. This depends on the species and grain direction of the stock. Soft wood will let the plastic barbs dig in some while hardwood won’t. Plywood gripped best.
Taking test assemblies apart was easier if the parts were levered rather than pulled directly apart because the plastic barbs can compress. That ability to compress also allows a little realignment of the joined parts. Remember, for these things to be any benefit at all every mortise has to be made at the tight setting. That realignment ability diminishes with every additional tenon.
Standard pva woodworking glue does not stick to the plastic. There are grooves that might increase withdrawal resistance in very stiff wood but the small dimension relatively soft wood I was testing seemed to simply flex enough to allow the tenon to escape. Withdrawal was only a little more difficult than without glue. In fact, once the tenon started moving it became easy to remove.
I bought these things as a possible alternative to Lamello Tenso fasteners for installing face frames. The FASTenons are obviously inferior but cost about 1/3 as much as the Tenso’s without the pre-load clips.
Since FASTenons are 38mm long I have to use the 15mm depth setting on the DF 500 for the 19mm frame stock and 25mm for the carcass. Driving the tenon into the carcass first leaves only 13mm to engage with the frame. Given the spacing of the plastic barb’s loosing 2mm doesn’t make any difference. They hold well enough for a pliable frame that doesn’t need much persuasion to fit. Tightening the fit with a hammer blow closes the gap but the vibration could loosen other tenons along the frame, so I’ll probably stick with the Tenso’s.
An alternative to the FASTenon is the
Lamello Bisco P-14, if you can conveniently make the right cut.
Scratch that. The Bisco is only good for surface registration. It’s withdrawal resistance is weak and even more affected by grain direction. One Bisco costs about four times as much as a 6mm Domino. And almost twice as much as a FASTenon.
If you Don have a Zeto the Tenso can’t be used so in that case the FASTenon could be helpful.
