Benchwork legs?

No ideas off the top of my head ... but, if I were you, I would consider Mianne benchwork.  Everything is included - and you can move it very, very easily.   

I would think you could use your 1 x 4 and make an L shape. Attach them to your table top using carriage bolts so you can take it apart if needed!

If you are talking table top sort of tables, just use 2x3s or 2x4s cut to length for legs and screw them into the corners from the sides of the 1x4s. 

Depending on how big you make the tables, you might want to use more on cross-pieces as well.  (example, if you use a 4x8 board as a table top, use a leg in each corner, and probably at least one cross piece (mid-point) and put a leg on each side there too (total of 6 legs)

You might need to describe a bit more thoroughly what you are trying to do to know what is compatible.  If you meant L-girder, then what I wrote above probably is meaningless.

Mike's idea of carriage bolts for attachment is a decent idea, but can become a problem if you want to put 2 tables right up against one another, as the bolts will cause a gap in between the tables.  (there is not a lot of heft to be able to countersink on a 1x4 - I'm thinking you start to affect the strength very easily if you try to countersink for a bolt head)

P.S.  I am glad to hear you like CO.  I know you were stressing when you were in the process of moving.

-Dave

Module builders have a variety of methods to attach/remove legs quickly, but I suspect that is more effort than you want for a set of tables that will be taken down once in a great while.  I have several  modules with quick setup pockets for 2x2 legs, plus additional modules, used once a year for a holiday show, without pockets where the legs get screwed in.  For a 24" x 48" up to a 48" x 48" table, a 2x2 in each corner works well.  (the 1-3/8" square pressure treated balustrades commonly available in builder stores are fine).  Attach the leg with a flathead screw from each side to lock it  into the corner.   Carriage bolts are overkill and the countersinking of the heads so tables can be flush is extra work.  A single table may feel wobbly but several tables connected together become stable.  Add diagonal braces if you want to stiffen up the tables.

I also have a set of 4 x 8 ft. tables with 1/2 ply decking on 2x4 frames that support walking on top.  These tables are supported by by a 2x4 in each corner, and a leg in the middle of the long side if flexing is an issue.  (These heavy tables are being converted to 4 x 4 ft tables for ease of transport and storage - if you are planning to eventually move layout tables, consider weight and size when building).   Again, I attach the legs using 2-1/2" flathead decking screws, this time using two screws on the 4" side and one screw on the 2" side.  I use Torx head screws as Phillips head tend to get stripped when backing the screws out during assembly and disassembly.

When assembling the tables, I use clamps to hold the leg tight in the corner when driving the screws.  A tight fit improves rigidity. 

Like Mike G. said.  Two 1x4s made into an L would be your strongest and least expensive way to go.  

The Fort Pitt High Railer modular layout used  legs made with 1 1/2" X 1 1/2" lumber that uses a clamp board.  There are two sets of legs/two clamp boards per module.  Legs also have height adjustment.

One of the larger modules, up on the saw horses, for extensive wiring.  Note the leg assemblies clamped in place.

Wing nut spring assembly on the move-able clamp board.  Most still are 5/16" carriage bolts and wing nuts, newer modules we increased the size to 3/8", more old finger friendly.

Legs and modules stored.

Leveling assembly.

5/16" X 5" eyebolt with star assembly.

There are braces on the turntable/roundhouse modules.   1/2" EMT conduit. with 1/4" wing nuts and bolts.

Quickest, simplest & very strong . Use 2x2 (fir / poplar) for legs (actual size 1 1/2).

Use 4 x4 and cut out 1 1/2  out of one corner.  Out of 8' piece, you now have 2 extra legs.

use eye bolt with thread inserts 1/4 or 5/16 " sufficient, to hold legs. 

Use threat inserts and elevator bolts for leveling legs.

attach modules together with c clamps or permanently  with oversized holes & washers for alignment. 3/8" or 1/2" bolts would be all you need.

we tend to over engineer things.

K.I.S.S. (keep it simple stupid) is my Motto anytime I start to get carried away with grand ideas.

pm email kevopelli@gmail.com for any pictures.

KevO