In part 2 of this series we looked at the baseboard design. Covering the the issues I’d found and the solutions I’d come up with to work around them using a Hollow-Core Door (HCD) as a baseboard. This time we’ll look at building a set of trestle legs for the layout to rest on.
What is a trestle?
The dictionary definition runs something like this: A trestle support (a.k.a. trestle legs) consists of a horizontal piece of wood fitted with four divergent legs that serve, together with at least one other of the same type, to hold a board at a working height.
They can be classified mainly in two families:
- Fixed trestle legs
- Folding trestle legs
We’ll be looking at the latter of these two in this article. Click the image (left) to view the trestles in use on the layout, along with the names of the parts and the orientation of the dimensions used in this article.
Why trestles instead of legs?
For other projects I’ve used legs as I was more comfortable in their construction than I was with trestles (they are somewhat simpler). Having completed the set for the Evans Hollow Industrial layout (formerly the Hollow Core Door/New Layout/Layout without a name layout) I’m a lot more comfortable with the design and build process, and surprised how well made and sturdy my creations are. So again, why trestles instead of legs? Well, there are two main reasons:
- Storage, and
- Simplicity of attachment
Storage and it’s advantages
There are two parts to the storage:
- Storage of the trestles when not in use, and
- Storage on the trestles when they are in use
For item 1: when not in use it is easy to store the trestle legs of the layout. They are remarkably small when folded; so that’s a big plus.
For item 2: when in use it is great to have storage available. Trestles when in use with a layout have most of the weight above the top of the trestle. This significantly raises the centre of mass well above floor level, which if incorrectly designed, leads to instability, especially where the trestle is of narrower width. You can mitigate the instability by using a wider span to offset the high centre of mass. However, adding storage across the lower stretchers (using a shelf for example) and adding weight lowers the centre of mass on the trestle much closer to the floor. Regardless of the given width the lower the centre of mass the more stable the trestle is.
There is one final benefit to having trestles about the house: they can be used for more than just the layout. Need a quick table for a party or get together? Whip out your trestle legs, a couple of 2x4s, and a board made from ply and you have a perfectly serviceable table.
Simplicity of attachment
For this layout you simply stick the trestle legs underneath the baseboard. Job done. I do have some further modifications to the baseboard to be completed to ensure the legs stay where they are put.
In open frame benchwork they can be located inside the framework. Job done there!
What I discovered during the build
Using a framing square is crucial to the successful completion of a set of trestles. When building trestles we are not using a framing square as intended (to build roof trusses) but as a long wood square to make the legs and cross braces square and true.
There are a bunch of videos on YouTube that will tell you everything you’ll ever want or need to know about the tool. For railway modellers building trestles all you need to know are that it’s a big metal square, with a a fat and a thin part. I used the fat part (called the blade) for locating the cross pieces with the longer skinny part (called the tongue) held down the side of the legs of the trestle.
This makes getting everything square and true a snap, so long as your boards are squared and you can buy your lumber this way from the big box store, which makes the whole thing easy-peasy.
Tools and methods
Tools you need
- A saw (hand or a powered circular/mitre model)
- A Framing Square, or if you don’t have access to one, get as large a sqaure as you can manage. In this case, size does matter, as it limits the errors that can creep in during assembly
- A drill (either powered of hand)
- A screwdriver (either powered or hand)
- Screws (no longer than 3/4 the thickness of your leg and cross braces combined)
- Glue (regular PVA or Carpenters glue if you have that on hand)
- Clamps (to hold the cross pieces while drilling and gluing/screwing together)
- DAR (dressed all round) Pine or other similar wood (I used Australian 4×1″ pine really 19mm x 90mm)
- 4 butt hinges 3 inches (75mm) wide
- Rope or chain for the trestle stop – I wanted my trestles spread 21 1/2″ (546mm) measured from the outsides of the lower stretcher, so you’ll need at least that length and about 20 percent more to tie knots if using rope
There are a couple of critical measurements here that I suggest you layout on your legs before beginning the build:
- Top stretcher – I chose to be about 1/2″ (12mm) below the top of the leg – but really anything between nothing and 1/4″-1″ (6-25mm) works – the closer to the top of the leg the upper stretcher is the better
- Bottom stretcher – 8-10″ (200-250mm) above the bottom of the leg – I chose 8″ (200mm) as this looked to me to be about right
NOTE: The Evans Hollow Industrial sits at 49 1/4″ (1250 mm) above the floor to the top of the baseboard (my diaphragm sits at this height which puts it slightly below my outstretched arm) which is perfect for me, allowing standing and operating without bending. Additionally the layout is at eye height for me sitting in an office chair – which is great for photography, and for when I just want to operate sitting down. It’s not too high for the younger members, not to low for taller members of the operating team; a good compromise height.
- The first step in making trestles is to determine the best layout height for you. I like something in the 48-54 inch (1220 – 1370mm) height range. Whatever the height you want cut your legs to that length. Sure you’ll lose a little because of the spread of the legs, but only an inch or two (In my case all the legs were cut to 48 inches (1176mm) on the mitre saw)
- Measure the width of your leg space (in my case the width of the door), and cut four stretchers to that width
- On your workbench or surface (I used a kitchen table btw) set out a single leg with a single stretcher at right angle to the leg and at a height that works for you below what will become the top of the trestle, then clamp the two together ensuring space to allow for the screw holes to be drilled
- Drill four screw holes in a square pattern on the stretcher, ensuring that they go into the leg (measuring with the twist drill in the chuck of the drill) to make sure that you have enough of the screw going into the leg piece
- Undo the clamp, and place glue on the leg face underneath the stretcher around the four screw holes you’ve just drilled – use the framing square to check for squareness
- Screw your four screws into the stretcher so that the screw thread is clearing the face of the stretcher by 1/16th to 1/8th of an inch (1.5-3mm) and locate the board to the leg again aligning the board with screws into their respective holes, then clamp again
- Tighten the four screws all the way into the stretcher and the leg, leave clamped
- Repeat steps 3-7 for the lower stretcher
- Remove the clamps from the first leg and prepare your second leg, using the framing square and clamps, then follow steps 3-7 again to mount the second leg. Once complete repeat for the second trestle
- Once both trestles are complete you’ll need to add the hinges. The Mitre 10 video show how to this so I’m not going to into that too deeply – keep in mind that if your top stretcher is at the very top of the leg, you can do as the video shows when mounting the hinge, if you’ve mounted them lower as I did you’ll need to modify that to as shown below in image 2 (click the image for the larger version)
- Finally you’ll need to drill a hole in the exact middle of the bottom stretcher on each leg of the trestle for the trestle rope – measure from both width and height and then drill a pilot hole, and a clearance hole for the rope
- Knot one end of your rope and per the video string it through the first leg, then the second, measuring for the width between the stretchers, then tie the second knot and re-check the measurement, you may need to adjust a couple of times here before getting it right (I did) – then repeat for the other side
And that is the whole process start to finish. Please do watch the video, and consult the plan. You do not need to make these exactly as I have. Make them the height and width that fits your situation.
Finally a note on safety: When you are using any tool, especially those that cut or punch make sure you are wearing eye protection at all times. Small parts can and will fly into your eyes if you are not very careful. I’m not responsible for any damage to you or others from using the information presented here.
- Plans (PDF format) and a video showing how to build trestles (Mitre10 NZ video)
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