There are production planes with laminated bent spars made of a lot of thin laminations. I am sure that a lot of them have bolts through the glue joints. My main reason for stating that you should not drill throught the glue joint was because it is very hard to keep a drill bit going straight through the softer wood and the harder glue. You will need to be very carefull and use a good drilling jig to make sure the bit comes out where it is supposed to.
Brian Kraut Engineering Alternatives, Inc. www.engalt.com -----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On Behalf Of Mark Langford Sent: Thursday, June 10, 2004 7:20 AM To: KRnet Subject: Re: KR>Spar lamination direction - Oops Steve Jacobs wrote: > My second reaction was to re-read all my material on glue joints. Every > indication is that a properly done glue joint is as at least as strong > as the host material. A scarf joint is allowed in a wing spar (cap) > according to AC43 - at an angle similar to the minimum spec on grain > run-out within wood, suggesting that a glue line is at least as strong > as nature's own laminations (wood-grain) - is this not the very reason > that a laminated beam is seen to be stronger than a single piece of > lumber (of the same size and wood)? Personally, I agree 100%. I'd still do it the way you are doing it, and have no reservations at all. If I build another one, it'll be just like you built yours. I'm not sure it's necessarily the glue that makes a laminated beam stronger (although is probably a contributor), but the fact that if there is a hidden knot inside a large monolithic beam it goes undetected, whereas in a lamination it would be culled out and replaced with good wood. Also, the wood grain isn't perfectly aligned between laminations, so there's a certain amount of "crack-checking" that goes on, like in plywood, which I would consider to be a good thing. Mark Langford, Huntsville, AL N56ML at hiwaay.net see KR2S project N56ML at http://home.hiwaay.net/~langford _______________________________________ to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
