"I'm thinking that's better

  Ripping 2 by 4's the wide way is not fun, 3 1/2 inch depth is a pretty thick cut for many table saws. I might consider ripping each of the  2 by 4's into L section with a 2 1/2 cut the tall direction and a 3/4 " cut the narrow way. .....DaveB

2x2's,

it's easier to rip and they worked fine for my bench work. I use scrap lumber all the time. I am using them in my sectional style 2x8 foam topped layout. I drill and use 1/4" lags in the bottom to level any uneven areas of basement floor.

Another 2x2 Job

I also ripped mine to make 2x2s.  Was easy to do and they have worked very well.  I'm using mine to support traditional L-girder benchwork.

2x2

I have also used 2x2 and they work fine.  The 2" thickness is also better if you plan to put a T-nut into the bottom for a leveling screw.

The 1x4 L leg can be made more "furniture" by putting a slight taper into the legs.

Of course if you do that you'll have to model the upper midwest to fit in with the "Danish Modern" benchwork. 

2 x 4 L girders

I'm with DaveB above that since you have a table saw making L girders out of the 2 x 4's using two cuts is the best use.

If you read the classic old model railroad magazines people were always using used lumber for layout building. When was the last time you saw a house torn down piece by piece?  Now it's claw on a backhoe and everything goes to a landfill.

Robert

Free standing?

or partially supported by ledge on wall. There are layouts so massive that heavy legs are required...especially if you will need to walk/crawl across the surface. Most layouts are fine with 2x2 braced legs. If the layout is supported with a ledge just about anything will work. I agree with others that ripping to obtain a 1x3 is not the best choice.

My layout is a ledge/2x2 leg job and solid as a ....well, you know.

BTW. A couple of buddies and I tore down a house piece by piece to get the materials. It was a long time ago and we were young, strong and broke. It was one hellacious experience. Here’s a tip. If the structure is stucco coated run as fast and far as you can before even considering the “free” lumber. 

I could be wrong

Oh, I should read comments before responding to them.

Used lumber

On of the saddest things I saw was a derailment of a plain flat car carrying bundels of 2x4's.  The derailment broke the straps on the bundles and scattered them, then the clean up process fractured most of them, front end loaders and side booms splinter 2x4's when they run over them.  70 tons of brand new 2x4's.  Bummer.

That is heartbreaking, Dave.

Overkill?

If it were me, I'd rip into 2X2's and forego making L-girders for the legs.  A 2X2 can support a substantial weight.  2X4's can hold up a house... 2X2's can hold up a layout.  

You're not really gaining the

You're not really gaining the advantages of L-girder benchwork by cutting a chunk out of a 2 x 4 as some suggested. The strength of the L girder comes, in part, from the 90 degree rotation of the grain in the two parts. Each if resistant to warping in a different direction, and the two glued and screwed together lend each other strength. By just cutting a chunk ouf of a 2 x 4, you're actually creating a stress concentration point at the inside corner and making it weaker.

You'd probably be better off making 1 x 2s out of them (ripping them lengthwise through the wide face, parallel to the short face) and making two real L girders out of the 4 parts.

Remember... glued and screwed!

Rip them into 1x4's

I make my legs from 4ft long 1x4's screwed together into an L shape.

Rip your 2x4's into 1x4's and then glue and nail them.  Or screw them togerther.  Or screw and glue them together.  I have done all three and all work fine, just don't skimp on the screws if you are not glueing them.

Back when stud grade 2x4's were pine I ripped them into 1x4's all the time on my radial arm saw.

One of the nice things about 1x4 L shaped legs is that they are 3 1/2 x 4 1/4 actual.  They make very sturdy legs and require minimal bracing.  In fact I usually don't brace them at all unless I am putting wheels on the bottom..  Anything smaller will require bracing.

Good luck

Paul

Thanks all, for the comments

I used 1x6s for my compressor enclosure

Taper

I am tapering my 2x4 legs down to a 1 1/2" square starting about 6" from the top. Loading is not an issue.

A vote for 2x2 legs

Several clubs I belonged used 2x2 legs for their modular layouts, including a G scale set-up with 36"x48" modules. Two legs per module, and modules bolted together makes a very strong set up. Additionally, a center-drilled 2x2 with a T-nut and a carriage bolt makes a dandy leveler. If you are really worried about stability, add a 1x2 diagonal brace about 1/3 of the way from the top end of each leg to 1/3 of the way from the bottom of the opposite leg.

Using 1x2, 1x3, 2x2 as benchwork

Jay offered the method I used... A 'T' nut in the illustrated 2x2, with a 1/4-20 bolt (or Connector Bolts - see cabinetry hardware).

Using only 3 sizes (plus desired fascia), my benchwork has 2 general assembled sections:

BTW: cutting the 2x4s to make these sizes is (inn my opinion) too much extra work.. most of the strength is inherent in the total cross section and the stiffness is inherent in the web (the vertical extreme)... the girder above is (nominally) 4 square inches with a 3 inch 'web' .  A 2x4 is 8 sq inches, with a 4 inch web... but has  twice the weight.    Perhaps ripping into 2x2's with a 1x2 added vertically below would reduce the labor and deliver far more strength than the 1x2 sections I used.

As long as your wood is straight (or can be assembled straight)  and dry, you'll be satisfied!

My layout is slightly lower

My layout is slightly lower than most (45 inches) but I was able to get 42" long deck railing spindles and use them with screw in leveling feet. Works create for my 2x4" modules. These pressure treated spindles were 92cents each at Lowes and only need 6 per module and then 1 set of level glides which makes it $10 a module in total.