Author Topic: Domino Jointing system - what are "Extremely high pull-out and load forces"?  (Read 3371 times)

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Offline sdes

  • Posts: 21
Whatever figures you find for strength of fasteners in wood have to be carefully considered.

For example the EZ-Lok insert pull-out figures are for installation in the side of boards not end grain in which case they have very low pull-out resistance due to the fact that the knife edge external threads neatly slice through the end grain severing it so the fastener pulls right out.

For end grain inserts the more common blunt thread style holds better but not well enough for a cantilevered load.

Very true, I imagine the extremely high pull-out force might drop to just very high or worse on the end grain.

Thanks for the input.


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Offline Cheese

  • Posts: 5150
Having said that, as a side note, the very old Larch timbers that the house is made of is extraordinarily hard. It is also highly resinous, which means it has an inbuilt "hotmelt".  Drive in a large screw with an impact driver and you have about 10 seconds to change your mind, once the heat generated from driving it in has dissipated and the resin re-set, trying to unscrew it will just rip the head off the screw.

The 28' tall larch newell that we have put in for the spiral stair is new (about 6 year old) larch though, so quite a bit softer owing to the faster way the trees are grown in modern French forrestry, and should be significantly softer than whatever fasteners we eventually choose.
(Attachment Link)

Interesting photo...the renovating process will be even more interesting. We’re eager... [smile]

As a rule of thumb, the pullout value in endgrain is about 25%-30% less than sidegrain.