|Forum topic by phlepper||posted 06-14-2011 10:32 PM||1174 views||0 times favorited||6 replies|
06-14-2011 10:32 PM
I’ve been asked to build a mission style swing for a family member using plans from a 1912 Popular Mechanics article (http://howtobuildplans.com/2010/09/11/mission-style-porch-swing-plans/). The project will be made out of left over cedar from a backyard pergola (so the swing will match).
The plans call for a lap joint between the bottom rails and the front and back posts. Then they call for a single 4” lag screw through the joint and into the end of the end rail.
I would prefer to make this without the exposed hardware so I’m wondering if I could instead use a mortise and tenon to attach the end rail to the front and back posts (through the center of the lapped joint).
Would this create a sturdy joint or would the mortise in the half-lap joint cause too much structural stress and actually weaken the joint? If so, any other ideas on creating a strong joint without the exposed bolt?
For particulars, the post and rails are all 2×4 cedar planks.
Also, any advice on the size of the tenon? All things being equal, I would plan on cutting the tenon to 1” x 3” (so 1/4” all around) and 1” long (not a through tenon). Although, if it would be better structurally, I have no problem with a through tenon for a little extra detail showing through the joint. Also, I’m concerned that at 3” tall, the mortise would cut through most of the lapped rail, so maybe the tenon should be shorter (1” x 2” perhaps)?
Below is a picture from the article (the joints are at the bottom on each corner).
Any and all opinions appreciated!
Thanks for your help!
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