Steel Benchwork ConstructionAdapted from a February 2002 Layout Design Special Interest Group presentation by David Griffy.
The steel C-Channel is often generically referred to as
strut and can be thought of as a giant erector set. One supplier of such material, the brand we use at SVL, is Cooper B-Line, a company with an extensive web site and a catalog. Another supplier of this material is Tyco Electrical & Metal Products. UniStrut is their brand name.
For specific details on what products we are using, you can click HERE.
Working with steel strut requires one specialized tool— a chop saw with a diamond metal cutting blade.
Cutting strut does makes two things:
- Lots of noise
- Sharp metal shavings which can give you nasty splinters
Please be sure to wear proper protection— eyes and ears need to be protected. Since most folks will need to rent such a tool, it also really helps to plan ahead and try to pre-cut the strut to usable sizes.
Once cut to length, the steel strut is secured using standard threaded nuts, bolts, and washers. The key to making the strut a solid foundation for building upon is making sure it is well-secured to the existing layout space. When we have an existing wall, we can attach the strut directly to the structure. This gives us a strong system for adding support brackets.
When there is no existing wall we make sure to bolt all free-standing strutwork to the floor:
and wherever possible, the structure is brought all the way to the ceiling and secured there as well:
In a few areas the strut is cannot be extended all the way to the ceiling. Here we take advantage of the existing buliding structural elements and use an L-bracket to secure the strut:
Shelf Brackets and Leveling
In additional to the vertical members, we use some horizontal strut. This strut is fastened to the vertical members using L brackets and bolts. Because the vertical member is C-Channel, we can use a laser level and slide the bracket up and down within the channel to provide us with very precise leveling of the benchwork supports.
Horizontal strut attached by L bracket to vertical
Below you can see vertical strut attached directly to the concrete wall. In this instance we are using prefabricated brackets to support the benchwork. The use of the metal channel makes it very easy to precisely level the layout by adjusting the height of the brackets.
We use two kinds of brackets. The more traditional brackets show above are somewhat less expensive but not quite as sturdy as the double welded brackets. "Less sturdy" means we can only allow one member to climb on the benchwork at a time, rather than two-- this stuff is quite strong when properly installed.
On the double bracket below you can see a piece of 1" x 6" pine. We screw the pine boards to the brackets to provide support for our open-box frame construction.
In this cluttered photograph below, you can see how the whole system comes together. Vertical channels are bolted to the floor. Additional stability is obtained from horizontal channel that is bolted to the building and also to the vertical channel.
1"x6" planks are mounted either on the horizontal channel or on the L bracket. Inverted open boxes are then bolted to the the 1"x6" to provide a platform for track laying and scenery.
Here you can see the general form of the benchwork. Where possible, the benchwork is standardized on 1"x4" frames that are simply joined together with glue blocks in the corners. 3/4" plywood is cut to fit the tops of the frames and homabed is put on top of the plywood, providing a flat, sound deadening surface for track laying and scenery.
Box construction does not prevent us from going around corners. As you can see here, we customize boxes where necessary. Plywood for this section will be cut appropriately. You can also see holes routed in the support beams. These holes are for the wiring harness.
Here you can see that the lower level is deeper than the upper. Also notice that in this particular section, the plywood has been cut shorter than the box frame, revealing the cross members. This allows us to use riser construction for sections where we don't want large flat expanses while still managing to have a flat base for construction. This area will have both a main line and a branch line, with the branch line vertically separated from the main.
Skyboard and Scenery
Here you can see another feature of the C Channel, as it is possible to simply bolt the skyboard onto the channel. The view is the back of one section of upper level skyboard.
Here you can see David applying spackle to the skyboard to cover nail holes. Eventually the skyboard will be painted again.
Here's a long view of one of the aisles, showing all of the construction techniques. On the lower left, modules from the earlier layout are being incorporated into an all wood construction section of the layout which includes a yard that is barely visible on the upper left. In the far back and on the right you can see skyboard and both levels of layout. The right section uses C channel mounted to the wall, while the back section uses free standing C channel (notice that it goes to the ceiling and is attached there.)
As a hint of where we're going, here's a later picture of the section on the right, showing track and the start of scenery construction. Those aspects of our layout are covered elsewhere on this site.
Detailed Strut Information:
We are using the 1 5/8" by 1 5/8" 12 gauge galvanized slotted strut (B-Line catalog number B22SGAL). The cheapest painted green finish should do just fine. It is can be sold cut to length and absorb the waste if you are buying enough and have the time. Standard lengths are 10' and 20'.
You can buy the strut in galvanized, stainless steel, fiberglass, powder coated paint, aluminum, etc finishes but why bother. If the atmosphere that your layout is in is that hostile, you have other problems. If you are going to put more than 750 pounds on a four foot span, you might want some of the other configurations. I have supported more than 4,000 pounds on some assemblies of this stuff. It is approved when appropriately installed for seismic installations for hospitals, etc.
The small slots (7/8" by 9/16") in the strut seem to work best in almost every application. With the holes, you don't have much fudge for adjustment. With the long slots, you are always cutting in to the slot when you cut the material. And without the slots, you will end up drilling much too much.
The anchors are not a B-Line product but are made by a number of folks. The most common name (but not absolutely cheapest manufacturer) is Hilti. Red Head and Ramset (I think) are other brand names. It is a commodity product. They are referred to as a 3/8" drop in expansion anchor. You drill a hole of the size specified by the manufacturer with a hammer drill. Any masonry bit and drill will work but a hammer drill is so very much faster. Be careful to drill straight and not "wobble" the drill. I suspect that you will develop an interest in ear protection and a face mask for the dust.
We use a turkey baster to blow the dust out of the hole but be careful not to get the dust in to your eyes. Then you drop the anchor in to the hole and check to insure that the hole is not too shallow. The top of the anchor should be just level with the concrete. Then use a hammer with an anchor setting tool and you are ready to go forward. There are all kind of depths to choose from but nearly any of them will provide far more than is needed. There are all kind of diameters also but as we are pretty much standardizing on 3/8" hardware and as 3/8" gives plenty of shear and pull out strength, we are using 3/8". The anchors are also available with male studs instead of female threads to accept bolts. For almost all purposes, the males are far less desirable. I have had nothing but bad luck with the self-drilling type.
Do not buy the channel nuts without either the springs or the plastic cups as they are not easy to use. Reference catalog numbers N228 (Spring Nut) and TN228 (Twirl Nut). I strongly prefer the twirl nut.
You will end up wanting to use three types of washers: Flat washers (Pretty much your standard every day washer); Fender washers (Similar to a flat washer but with a larger diameter; And no twist square washers (B201D).
You will want a variety of bolt lengths. Most of what we use is 3/4", 1", and 1 1/4" but we also have used 2" and 3" units. Washers cover up for a lot of slop in the length of the bolt. Don't get suckered in to using square headed bolts. We have chucked up a socket in to a battery operated drill when we are doing a lot.
We are using the B279 post bases but any of them will work.
For brackets, take a look at B191-18, B192, B494-30, etc. If we were going farther than 30", I would use a pair of B327's with a short piece of strut. We use a 1/4-20 flat head phillips screw with washers and nuts to secure a 1" by 6" piece of lumber to the bracket and we attached the bench work to the 1" by 6" with plain old dry wall screws.
You will eventually want some B101 and B230 two hole corner angles. The advantage of one over the other is that you are limited to an open ended wrench with one (and can have problems with the direction of the bolt) and the other is much more user friendly (B230).
I also find that we occasionally need some of the flat splice plates similar to a B141 and B341. Take a look at the B133 and B140 angles as well.Back to the top of this page
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