What advantage does L girder have over a box frame? I have a construction background and for the life of me I can’t figure an advantage.
Four advantages (in some situations) I know of, probably lots more.
- for those without a construction background, it requires less precision in construction.
- Much easier to adjust a joist location in an under-construction or partially completed L-girder environment than to try to move the “spar” in a box if you find it interferes later with something important (switch machines, underpass, etc.)
- L-Grider leads to the building of benchwork as “bridges” rather than “tables” and thus (hopefully) less overbuilding. Same can be true of grid, but L-Girder is a bridge by its nature
- Slightly easier to accommodate scenery that dips below the “baseline” level
All that said, the style of benchwork to be used is generally the least critical decison one has to make in building a layout. Most layouts I’ve seen or planned would be best served by a mix of benchwork styles for different areas: shelf brackets in some, grid in flat areas, L-grider in areas of varied topography.
This will no doubt de-evolve into another philosophical war. But the fact remains that nearly any style of layout can be built on nearly any style of benchwork. Getting it planned and built is a lot more important than ruminating over how to support it.
Linn Westcott originally intended L-Grider to make it easier for less-skilled woodworkers to build a light, strong framework quickly with minimal power tools.
Regards,
Byron
I think another advantage is that the L-girder is half an I beam, hence is more rigid with less wood.
The basic advantage is that the benchwork can be more free-form and curving at the edges. This allows the benchwork to follow the track better than straight box construction. It give you a lot of flexibility on your support and riser placement. It is also, due to the inherent strength of that L-girder, a little stronger than standard box construction.
By attaching the legs to the L-girders they stay back from the aisle, so they don’t get bumped or kicked and are out of the way of feet during operation.
Later in construction, that curved front edge helps when you add the upper lighting valance and lower fascia. These curves make it nice for the aisles, especially with a walkaround type of operation.
The picture below shows a little of this curve at the bottom left, this curve flows around with various radii as it follows the main around about 220 degrees of curvature, passing through a view block part way around. Under this area are two levels of 4 track hidden loops. The benchwork in this area is standard L-girder with 1x4,s radiating out in a circular pattern to allow us to space the risers for the best support.
If you aren’t building a curving, walkaround plan, box construction might work just fine.
There have been many articles over the years on the subject, and I’m sure many debates on this and other forums on the subject. It all comes down to what you like in the end.
I can tell you that it is strong, we have been up on the railroad a number of times with no problems and neither of us are little guys, I’m 6’ and Ray is 6’6", and we haven’t been skinny for a looong time.
D’oh! I can’t believe I didn’t mention this one. Certainly true.
One can also build curving fascia with box grid, of course, but it requires a bit of extra work and it comes more naturally with L-Grider.
Regards,
Byron
I just built two sections of my benchwork with L-Girders made with 1X3’s with 1X2 flanges. I find that after the two pieces are screwed together to form the L-Girder it is solid, it will not bend or break, and is quite sturdy! These are placed on the wall mounted side of wall brackets and screwed into the wall for extra stability. I am a big proponent of the L-Girder system. Photos will be forthcoming later this week on my layout website (see googlepages link below).
The L-girder has resistance in two axes (or axises, if you prefer…[xx(]). The vertical member has its inherent strength resisting sag, while the less wide piece glued at right angles to it resists the vertical sag that much more, AND provides lateral resistance…to sway.
Believe me, they work.
Well I do know carpentry and I still prefer L girder for floor layouts [as opposed to coffeetable, hanging, shelf, etc]. It uses a LOT less wood and is FAST and has many benefits over a sheet of plywood on legs in my opinion anyhow.
Also I can use risers and adjust them sooo much more easily with Lgirder than I can any other way.
Having said that, the sheet of plywood method has its merits as well. More stability for one thing. Can in some cases be easier than fiddling with individual pieces of wood. Also accomodates the cookie cutter method [both do actually].
So lots of ways with each having benefits.
SpaceMouse I hope that helps somewaht.
a feature I like with L girder is that cleats and risers necessary to raise and lower track road bed are a lot easier to install on the crossbeams of L girder than they are for box grid construction…
While there are a great many positive facets to employing L-girders, most of which have already been pointed out, I believe LW thought the greatest of these was rigidity relative to the use of regular lumber. Remember, LW created the L-girder design in a time long before foam scenery was a reality and guys were using huge amounts of heavy plaster scenery.
L-girders are at least twice, perhaps three times, as strong and resistant to distortion under load as conventional lumber of the same dimensions. Basically, they are 2/3’s of an I-beam design. As someone mentioned upstream, a man can walk atop an L-girder layout (I’ve crawled around on the top of mine once or twice)…something I surely wouldn’t attempt on any simple open-grid design made of 1x4’s!
CNJ831
Hey Chip, I will also chime in to say I agree with everything posted so far. While many different types of support will work, I find the L girder construction to be extremely strong and easy to use.
In this photo, notice that the table top is supported by two L-girders. Only 4 legs that are well inside under the table. This allowed me to put the angles easily on them, have a strong and sturdy table with a minimum amount of work and lumber. Notice the L-girder along the back wall. It is tied to the L-girders on the side benchwork and has no leg under it on the right end. It is very strong and will not move. I have already climbed up on it without a problem and I weigh 280 lbs.
Notice the open area that is available for under table access to the staging area if needed. Plenty of room for even a “heavyweight” like me to fit in there.
So what I’m getting here is that the reason of the L-girder is a matter of torsional load, which I’m not sure there’s a lot of on benchwork. I’ve seen pictures of Chuck’s benchwork and you could drive a truck on his roadbed. But I’m not sure that an L-girder has any particular advantage there over an open box frame. Certainly the “L-girder” aspect has little to do with framing a curved facia, you merely cantilever your framing to match your design.
Still, I’m willing to be wrong here. What am I missing? Is there the implication that plywood is involved in box construction? Jeffers, you out there?
L-girder certainly does give you the best strength for the amount of wood, but with a plywood-free foam-based layout, I looked at the options and decided that L-girder was unnecessarily complicated. I just don’t need that much strength, and I preferred simplicity of construction (I’m not carpenter, either), light weight and rigidity. My layout is on casters, so I really want the legs at the edge of the table for stability.
With foam, you can’t climb on your layout anyway, and I really don’t need to drive a truck on it. That led me to use a simple box frame which encloses the foam, rather than simply supporting it. If I had used plywood, I would have needed a much more substantial sub-structure, though, so maybe that’s the difference?
Chip, there can be plenty of sagging and torsional distortion in simple box construction benchwork unless you employ an overabundance of supporting legs, both at the edges and in the middle. I’ve seen it many times myself, both in layouts built years ago and some constructed today. The concept of L-girder support was revolutionary when LW’s article appearred, solving an age-old problem in the construction aspect of the hobby. One need only look at old MR articles to see the “timber” often used to construct early layouts so as to avoid warping of the pike in one direction or another. How you can miss this point is beyond me.
CNJ831
CNJ,
If I built a box frame the one thing it will not do is warp. Any support you give to an L-girder system you can give to a box frame.
Chip. one other nicety of L-girder construction is the ease of screwing the cross supports to it. The 1 x 4s used above the L-girders is screwed in place with 1 5/8" drywall screws from underneath. Depending on the materials used and the placement of the layout, etc. box frame construction may work out very well for you. This is again one of those personal prefence things that can be done several ways.
Maybe if you are related to Norm Abrams and have his workshop you can but the average hobbyist I’ve encountered can never say that and I’ve seen a lot of unstable layouts in my time built using box frame construction.
CNJ831
Several other reasons were listed, Chip. Did you not see any of those? [:)]
We get it that you were in construction and can build things well. It’s not true for everybody and L-girder offers we mere mortals an excellent shot at getting it right the first time – often with less time, money., and aggravation invested. Some of the “table” benchwork displayed on-line is so over-built it could support live steam instead of HO.
If it’s not right for you, then don’t use L-Girder, for Pete’s sake.
Again the main point – most any type of benchwork will work for most any style of layout and most larger layouts will benefit from a mix of benchwork types. I have known a lot of people who noodled, cogitated, quarreled, and queried on benchwork type for so long that they could have built it in half the time it took to make the decision – and sadly, that’s not an exaggeration.
Regards,
Byron
Two things not yet mentioned:
L girders don’t HAVE to be wood. I helped to build a club layout where the L-girders were dexion, really heavy pierced angle iron. My own “L more like C” girders are 16-gauge steel studs.
With L girder construction and the roadbed carried on risers, the cross-joists don’t have to be made from dimension-specific lumber. ANYTHING can be used, including odd pieces of crate wood, steel studs, chunks of 2x4 from the scrap wood pile or whatever.
I agree that L girder construction should not be a universal standard, but it is very useful for all of the reasons already mentioned in this thread. While some of my layout is mounted on shelf brackets, all of the freestanding tables are framed with L-girders.
Chuck