Help with L-Girder Benchwork

I like your design.  I would add another diagonal (red) to each of the 2 legs that don't have them.  This would greatly strengthen the legs in that direction.

You are correct.......you did miss my comment in the second paragraph that I only show the rear supports but will have them in the front as well.

You may want to consider placing gussets at the bottom of the side braces where it joins the leg.

Another variation is to use smaller L-girders for the joists and screw the deck to the L portion from the top or the bottom. Easier to hit quickly with a screw as it's wider.

Make the holes in the joist for wiring runs before installation.

Are you planning elevations?

Looks good.

What a good start

If I may suggest…. I would add diagonal braces to the L girders also. Will keep your frame square. Also I would make the L girders out of all 1x4s. That will stiffen and make the L girders straighter.

clem

Use long screws to attach the casters.  Screws don't grip well when screwed into end grain.  Additionally, I'd try to find casters that lock caster  rotation as well as wheel rotation.  They provide MUCH greater stability and have proven to be well worth the additional cost whenever I've used them.

I wish I could recall but there was a guy on here less than one month ago that did this and whatever he did worked well.  Great idea to understand that you need access...good planning.

GES, 

I agree with the comments regarding additional bracing, and Pat's suggestion about the casters. I'd also suggest that if at any point you'll be cutting parts from wider pieces of lumber, that you batch cut them. In other words, cut all of your pieces of a given size all at once before moving on to another size. This will provide you with consistent results for the same size pieces. Best of luck...

Andy

I do like the idea of adding the gussets and I am glad you referenced adding the holes for wiring before install.  With regard to using small L- girders for the joists, I understand your logic of "easier to hit quickly", but it would seem to me that it would make it stronger to run the screw up into the 1 x 4 directly.  By doing that it seems it would also eliminate the need to make the joists like an L-girder.  Am I missing something in my logic?

Clem,

You stated I should add diagonal braces to the L-girders.  Is that not what I show on the drawings in red.  I only show the rear braces, but would add them to the front as well.  If that is not what you meant, can you explain further.  I show 1 x 2 lumber on the top of the L-girder because the book I read indicated 1 x 2 lumber was good up to 20 feet.  I will consider increasing the top to a 1 x 4 as well.  Thanks.

Pat,

The screws I bought are 1 5/8" long.  Is that long enough?  I have already purchased the casters.  I got two with brakes as in the picture I included and two without brake.  I did look on the internet and found a caster as you suggested.  With the weight of the table and scenery and trains and with the two locking casters locked, would I really get any movement?  Can you tell me what the casters you referenced would improve upon over what I already purchased.  Thanks

You use cross bracing on your legs to keep them square and stable, do the same for the deck to keep it square. They don't have to be as long as the deck. Just because the the L girders are parallel doesn't make the deck square. A rectangle as four parallel lines and each corner is square. a parallelagram has the same lines but corners are not square(90 degrees). A two foot piece of plywood decking on each end, would also work to keep it square and stable. if you are covering the whole thing with plywood than cross bracing is not needed.

When I responded earlier, I did not address your question of elevation.  My plan calls for three levels.  The first level will be at 36" from the floor and levels two and three will 46" and 56" respectively.  I do not plan any changes in elevation on each of the levels other than the stated heights above the floor as list above.

No, you are not missing anything. It's only longer holes to drill and longer screws. Just a variation that I've seen.

Cutting all like dimensions at the same time is a great idea.  Thanks

Your comparison to rectangle vs parallelogram is the perfect explanation.  Sure makes sense to me now.  Thanks.

GES1413,

Your description and drawing are correct. 

Gussets are recommended.

Well done!

Thanks for the kind words.  Ironically, just before your response arrived, I realized I do have an error in my description.  I said the legs are 2 x 3.......they are in fact 1.5 x 3.  Just for the record, my drawings were correct, the written part was in error.  I did get quite a few responses and some good ideas to make a few improvements.  Thanks to all.

George

Ges:

Yes, you will get movement as long as the casters can swivel. Not much, but enough that it might be annoying.  It might not bother you, but you can always change the casters later if it's a problem.

Your 1-5/8 screws might be OK.  I'd be more comfortable with longer, but as long as you have deep threads, you'll be OK.  And whatever you do, DO NOT use drywall screws.  They're not very strong and will snap if your casters ever meet any resistance.

Your design looks great, but I also agree with the folks that advised gussets where the diagonal braces attach to the legs.  1/4 plywood would be adequate for these and will add a tremendous amount of rigidity to the whole structure.

Pat,

Before I decided to use L-girder, I was thinking of an open frame with 6 legs.  Thus I bought six casters like the picture.  After reading your last reply and doing some research, I agree with your comments and will replace them with the ones that do not swivel when engaged.  I can and will get a longer screw as well.  Better to be safe than sorry.  There were other good suggestions offered after my initial inquiry.  I discovered this forum a few months ago.  The responses from people that want to help have been great.  Thanks.

Your local Home Depot or Lowes should carry 2x3s so you won't have to cut down 2x4s.  Just to save some time and effort.

As far as those caster screws go I would get at least 2" screws.  And as Pat suggested do not use drywall screws.  Number 8 or number 10 phillips head.

Rick

RICKC and John C.

2" screws it is. 

As for cutting the 2 x 4's, I have enough of them left from a construction project that I have no other use for.  They are top quality and perfectly straight.  My original intent to build the benchwork was to use select pine.  My local building supply also sells poplar.  Each piece is only a few pennies more than select pine.  Each piece comes individually wrapped and all are perfectly cut at the ends with no knots, bows, etc. and I understand they take paint better than pine. 

When I say I want to cut the 2 x 4's all I plan to do is cut them to correct leg length and run them through the table saw just to square the edges like the poplar....I think that is the accountant in me!

George

Well, if you have a table saw that's great.  Cut away!!!

I was looking at your caster.  On second thought you may need to use a number 10 or number 12 screw rather than a number 8.  Number 8 might be a little thin for the caster hole.

Rick

I will inquire at the hardware show what size screw makes sense and I know I will also need to ask what size drill to use as I assume I should have a starter hole so I do not split the leg.  Something else I did not mention regarding getting a 2 x 3 or cutting a 2 x 4.  I wanted a wider leg and by cutting the rounded sides from a 2 x 4 I get a width of 3 to 3.25 inches.  A 2 x 3 will limit that width to 2.5 inches.  The center to center on the holes of the caster shown is 2.375 inches.  I will put the leg issue on hold until I search out whether I want change the caster to a dual locking wheel.  That may change the bottom leg dimensions depending on the plate size of the caster.

I am curious as to why you use 1x4 vs 2x4 for your joists, especially if you already have good 2x4s available. As for as your other construction methods and the suggestions offered, they match up closely with Model Railroad Benchwork book. I was thinking of building my benchwork similar to yours but using the 2x4 joists because they are less expensive and would seem to be easier to attach on edge (1.5 in vs 3/4 in). Maybe there are reasons not to use those that someone here may describe.

are you building a house or train layout? If a house, please use 2 x 4's!

After you build the 2 x 4 table, you will need to do scenery. Somewhere along the line

you will need to get between the joists..............2 bys will get in the way!

somewhere along the line, you will need to relocate a joist(s)

somewhere along the line, you will bump into or run into your layout, if you use 1 bys,screws and glue, as you bounce off the table, you will note that is stronger than you are! Maybe then you will realize that 2 bys was over kill!

oh, I speak from experience! if you have 2 bys and a table saw, you can make 1 bys quite easily!

I never cease to be amazed at folks that build with 2 bys & plywood, then wonder why

they have a problem with noise. What they built was a drum!

My reference to using 2 x 4s was only for the legs.  I do have enough to complete the legs only.  I am comfortable using 1 x 4s for the joists.

GES1413,

I'm am no expert to this L-Girder stuff, not by any means, but you will definitely hear "overkill" probably too much.  While I understand the concept, with legs, there should be no problem with using the 2 bys.  I planned, and my initial design used 2x4s for all of the benchwork.  Depending on cost, I may stick to it, maybe I won't, who knows.  Overkill?  Kind of an exaggerated work if you ask me.  

Mike

Just discovered your post and have a few things to add.

1)  This may have been mentioned and I may have missed it but you should also add diagonals to the outside of each leg for added rigidity and support for the 32 inch overhang at each end of the table.  Each leg would have three diagonals attached to it).

2)  Having worked under layouts and bumped my head a lot, I have found that cutting a 1 1/2 inch 45 degree triangle off the end of each board and girder will eliminate those sharp corners right where you will be trying to get up.  If you own or have access to a miter saw, this is easy to accomplish.

3)  Although many prefer to drill holes to accommodate routing of wires, I really prefer using plastic conduit straps.  By only screwing down one side, wires can be laid out under the table and just laid in the strap by flexing the side without the screw.  They come in sizes for 1/2 inch to 2 inch.  I have been using these for over 25 years on many layouts and have only broken one.

4)  I would use small lag bolts to hold the casters on for several reasons.  If they become loose, a wrench can be used to tighten with out jacking the whole table up to use a screw driver.  Also, should one become loose and not be able to grab, it would be easy to take it out and replace it with a longer one.

5)  Since your table is only six feet wide, I would place the girders only 4 to 6 inches from the end of the joists.  That way, should you ever want to make the table wider, an extension can be cut about 12 inches longer than the extension and scabbed to the existing joist with screws and glue.  Because the extension is resting on the girder, this configuration will give you incredible strength.

Good luck on your project and happy railroading,

Don

I will definitely add diagonals to the outside of the legs, I redrew the plan to show 45 degree angles on the joist and girders and I also purchased lag bolts to attach the casters.  I plan to evaluate how I will attach the wiring.  As for expanding the table size, that will not happen, so I will build the benchwork as per my original plans.  Thanks for your suggestions.

Final results.................

I want to again thank everyone who responded to me query.  I considered all the suggestions and went with just about all of them.  I am including three pictures of the benchwork final design.  For clarity I am only showing supports for one leg, but of course the same design would be applied to the other legs. 

The changes made were as follows:

1.  Added diagonals to the outside of each leg.

2.  All casters will be dual locking and attached with 2" #12 lag bolts

3.  Gussets were added to the leg supports

4.  I reduced the number of joists to allow enough room to pop up from the bottom.  Of course I will place where needed regardless of this drawing.

5.  I added a 1 x 4 attached to the end joists to allow me to square up the girders.

6.  The joists and girders will be notched at each end to eliminate bad head bumps.

7.  I will support the wires with conduit straps instead of drilling holes through the joists.

The table will be 6' x 14' and the layout will be three levels.  The joists are 6' 1 x 4's, the girders are 1 x 4 and 1 x 2 and the legs are 2 x 4's trimmed to 1.5 x 3.0 which results in a 3" square at the bottom of the leg with the added piece to support the plates on the casters.

This forum is great and I really appreciate the response.  Happy Railroading to all.

George

Not sure why the pictures doubled up.....sorry about that.