Following the comments in Linn Westcott’s book on L Girder constuction, if I read correctly, 2x2 legs are 1)attached to joists not L girders and 2)using #8 x 11/4 wood screws. The following are questions to someone with experience: Am I reading accurately? If I put my legs on casters so the (4ft x 11ft) table can move, will the joints withstand the force delivered through the to the leg in order to make the table roll a foot or so? Further, it seems to me you have to select one or the other direction in order to install a really good 45deg brace; if you space it by the thickness of 1 piece of 1 x 3 away from the Girder toward the inside, your angle brace will be very firm in the direction of the Girder, but the brace going inwards parrallel to the joist and coming up and attaching to the joist will inevitably be slightly out of parrallel to the joist. Is all of that correct, or am I missing something(s)?
Further to above, are those screws really up to the job at all (maybe that’s the first question, in reality)?
Stuart…Check our my website noted below. You will see L-Girder construction photos. You will see gussets and x braces too. My first table was all L-Girder and it had casters to move. Worked perfect. My table was 5’ x 16’. Plans are on the website.
Instead of screws for mounting the legs I’d use 1/4" or 3/16" carrage bolts through the leg and girder.
The legs are attached to the L-girders. Temporary keeper joists are attached to the legs to stabilize the table when initially setting it up. These can be removed after the installation of the table joists.
Roger…He’s building a train table and not a jungle gym for his kids in his back yard. [swg] If you plan to walk on it, yes it needs to beefed up. The L girder, truss leg combo is a very strong system. My 16’ L girders do not sag. One thing that is intersting is the cheapness of the table because so much of it is built with 1x2. I could have used 2 - 1x2 glued together for the legs.
So far things are working out OK, but I never thought of the pairs of 1x2’s as a replacement for 2 x 2 which can be hard to find. I have installed 4- 2 x 2’s, and plan to add 2 2x3’sif I can’t find a little more 2 x 2 lumber. But to the point of the last post, I may drive in some 1/4" carriage bolts, now that the suggestion was made. I’ll feel better.
The next time I teach a structural engineering class in Strength of Materials, Stuart and Roger I want you guys to sit in the front row so when I give the quiz you will know the difference in moment resisting connections and pinned connections. [banghead] Just trying to save you some $$$$$. Of course you will need to sit in the class for about eight weeks and learn about Moment of Inertia, Shear Strength, Compression and Tension, Mohr’s Circle, Deflection, Bending Moment before we discuss connections, but it will make you a better man. [:D] Next semester we will get you educated in indeterminate structures, like five span continuous beams with moving railroad loads.
Buckey, you’re forgetting lessons on sizing mat foundations and anchor bolts to support our benchwork.
Buckeye - I used the carriage bolts to allow easy leg removal if/when it is necessary to breakdown the layout. I also made my bench work using L-girts for individual tables that are bolted together. Only problem after scenicing I’ll need a Sawsall to separate things. Being retired never know when we’ll decide to down size and I doubt I’d find a buyer interesed in paying additional for a train layout.
Roger…then you should be using wing nuts to make knock down faster for loading into the moving truck taking you north to the snow and ice. [(-D]