Monday, April 20, 2009

Notes for Bob Q

Hello Bob:

Thanks for your kind comments regarding Dowelmax. I am still quite annoyed about the tests undertaken by FWW, for various reasons, but primarily because the testing was undoubtedly flawed.

My son and I did a destructive test yesterday (Sunday) and we video taped the procedure. Five dowels on a 1 inch x 4 inch (oak), the first test with 1 inch penetration, the second test with 2 inch dowel penetration. In the first test with the 1 inch penetration, the joint did not fail, the wood failed at 750 lbs. per square inch. In the second test with the 2 inch penetration dowels, the joint failed at just over 1,000 lbs. per square inch.

My point is Robert, these pressures, in my opinion, are absolute overkill, and I would estimate (without testing) that 400 to 500 lbs. per square inch would be adequate in 99% of situations.

The test undertaken by FWW was different from our tests, but of course that makes no difference so long as all other aspects are equal. In every single one of our tests the multiple dowel joint has been as strong if not stronger than a comparable mortise and tenon.

Having said all that, we appreciate your comments, your support and the time you took to try to resolve the perception. I think my son intends to include the video we made on our web site and our old destructive comparable testing is already on our web site if you would like to view it.

Once again, thanks and regards
Jim