Since buying my mill I have sawed out the lumber that I will need for my 32x80 machine shed. I am building the trusses myself using the green oak that I sawed. Building the trusses has involved setting up a jig made out of 3x3 angle iron bolted down to my shop floor. The trusses are coming out just beautiful. My problem is that I can't find a suitable gusset material that won't split on me when I try to nail the trusses together. I've tryed 2x4 oak, 1/2 and 3/4 inch sycamore, 2x6 oak, even 2x8 oak........it all splits. I guess I'm going to have to use plywood even though I was desparately hoping I wouldn't have to buy any lumber for this project. The trusses are built out of 2x4 oak that span 32 feet. My question is if I use 3/4 plywood, what size do I need to cut the gusset plates so as to adequately support the webbing? Any help would be appreciated.
I made some cottonwood trusses few years ago. Went dumpster diving in a new Johnson County subdivision and came home with all kinds of scrap 1/2" to 3/4" plywood. As far as size just cut it to what looked strong nuff, spread glue, and nailed em in place. The barn ain't fell down yet. :)
Might want to try this, don't know if it helps or not.
http://www.public.iastate.edu/~mwps_dis/mwps_web/tr_plans.html
Iwas splitting some green stuff so I switched gears and went to drilling and screwing- no splits.
Speed's a great thing but strength is what I want in a truss.......... ;)
The last few years, they have cheapened the plywood. Some of the plywood you now get is only 4 ply and his not as strong, the inter two plys run in the same direction. For gussets, I would look for at least 5 ply and 7 is better in 3/4 inch plywood.
Make two gussets, glue them together with gorilla glue, then pre drill.
I would use a gusset that covers at least 8 inches of the 2X. This would give the top gusset a dimension of 16 inches across X 12 inched vertical if I am following your design. I would use at least 5/8 and screw it and glue it.
I thought I heard once that gusset stock should be twice as long as the width of the piece on each side of the joint.
So if you're doing a 2x4 truss then 8" on each side of the joint = 16".
Jim Rogers
Thanks for all the replys and good suggestions. Many of you have suggested glueing the trusses. Will glue adhere to green lumber?
What I was thinking Farmer is first glue two large gussets together of dry 1x or so, or reasonable dry. I would make the gussets wider the better, but glue (completely coat) together 2 halfs of material then you've made a glue lam that won't split. Then pre-drill those.
As far as gluing those to your trusses, there prolly is a glue that you could call around and find to use with green lumber, but I don't know what type.
You can use steel, but that stuff is pretty expensive these days.
Gorilla glue gets a lot of press but there are other cheaper glues in the same family. Pro-bond comes to mind. Look at the ingredients on the gorilla at a HD and then you'll know what to look for.
The way this kind of glue works is that , when working with dry wood, You have to wet it!
The glue follows the water into the wood and gets better penetration/ adhesion so green wood has some water in it but I'd still wipe a wet sponge across the surface prior to squirting the glue. It's also advisable to spread the glue a bit to increase surface contact.
Make a trip to your local big box store. They carry a full range of construction glues. Come in caulk type tubes. One of the common uses is to glue subfloors to the joists. Read the labels closely and you will find one or more for use on wet wood.
Sorry can't remember the brand names I have used in the past but they worked well.