You can build a standard 4-by-4 foot platform to be used for theatrical productions, including legs and/or casters for added height and moveability. This platform works best for a modular setup where there is a need to platform a large stage area. The sections may be connected together to fit most configurations. If you decide you would like to create a different size frame, such as a 4 by 8, the basic construction method and steps are the same. You would simply use the appropriate-sized lumber.
Instructions
Building the Frame
1. Cut the lumber. Take your 8-foot 1-by-6 pieces and use your circular saw to cut them in half so you have six 4-foot rails. Put one rail aside. Trim three of the rails to 3 feet, 10 1/2 inches. Make sure to cut squarely, as you need the ends to be flush for proper joints. If air exists within joints, this may cause the platform to creak during performances as people walk across them. Unless you have the 3/4-inch plywood sheet cut down at the lumber yard or home center, you will need to trim to 4 by 4 feet. Remember, in plywood tops, it's better to under cut or be slightly less than 4 feet. This will help when attaching multiple platforms together, if needed.
2. Lay out the frame. Take your five rails and lay them out as shown in Figure 1, which shows the frame from above. In this configuration, the screws will not all be drilled in the same direction, allowing for more stability. The frame consists of two 4-foot rails horizontally, top and bottom, with two 3-foot, 10-1/2 inch rails vertically. Don't get too worried if the frame isn't exactily square because the top can cover up little mistakes. The odd rail should be centered inside the frame. It is best to mark and drill pilot holes where you will attach the rails together. Drill pilot holes through both pieces of wood and countersink them. This is an important step, as it can help prevent joints from loosening if a split occurs. Draw a line (in your head if you have a good eye) about 3/8 inch from the end of the long rail and position the holes close to the line. Make sure you drill pilot holes straight into both pieces of lumber. Try to keep the tops of the frame flush to each other when you drill.
3. Glue/drill the rails. Now that your rails have pilot holes, you're ready to drill your first joint. First, apply a thin coat of wood glue (white glue is OK) to the end of the short rail. The reason for using both glue and screws is that the glue can help curtail creaking noises by filling up any air pockets that may occur due to an uneven cut or slightly warped wood. This is crucial because you don't want the platforms to be louder than the actors. The glue also provides great strength. Reassemble the joint, square it up and drive the three screws. Make sure the two pieces of wood are in solid contact with each other. Wipe off any excess glue and then continue with the other joints. If you notice slight uneveness with the frame as you go, make a mark to show which way is up. Any discrepancies should go to the bottom of the platform. Remember, once you screw down a glued joint, you only have about 10 minutes to pull it apart and fix it if you make a mistake. You should have drilled/glued six joints when finished. To help in keeping a joint square when using glue, a pipe clamp can come in handy. Just clamp between two joints as you drive the screws to prevent slippage.
Attaching the Top
4. Lay the plywood on the top side of the frame. Make sure the frame side you marked as the top is up. Look at your plywood and put the "good side" so it is facing up. Most plywood has one side better than the other, usually marked by a price or UPC sticker. You don't want an actress' high heel to get caught in a nasty knot. Figure 3 shows the three ways the plywood can fit on the frame. The first way shows that a lip is created or the top is "proud" of the frame. Don't ever lay the top in this manner, as it will prove difficult when trying to attach different platforms together. The second drawing shows the pieces "flush" with each other. This is great, but it can take a lot of time and energy trying to keep a "flush" edge on all sides so it's not worth trying. The third way is the best fit, with the plywood just "shy" of the frame. But remember it should only be slightly "shy", such as an 1/8 inch, or a gap will be created that can cause problems when units are joined together. This method allows for some wiggle room so you don't have to be so concerned about making sure the top is cut perfectly.
5. Draw a line (in your head if you're that good) 3/8 inch from the edge of the frame all the way around the top. Space about four screw holes along this line, plus three or four on the central rail. Drill the pilot holes and countersink.
6. Apply a little glue to the top of the frame, lay the top and drive the screws. It is important to have the screws be flush with the plywood because if they stick up, they may hurt someone. Prevent any air pockets from occuring to prevent the crreaking noise when the unit is used during a production.
Adding Legs, Casters and Paint
7. Add legs. This basic platform is about 6 inches high, but a production may require a greater height. To add height to your platform, you need to add legs. There are two basic leg types. The first is the two-by leg. It is a simple design that holds up for most uses. You simply cut a piece of 2-by-4 lumber to support every corner of the platform and stick them underneath. Figure 4 shows the 2-by leg from a perspecitve underneath the frame. Place the leg (at whatever length you've determined you need) flush with the plywood top so it bears the weight. Attach the legs with 2-inch drywall screws driven in from the outside of the frame. Drill the screws in a circle or triangle, not a staight line, and throw in one or two near the edge for safety. For stability, make sure the legs walk around the unit with the narrow end of one leg perpendicular with the face of the next leg.
8. Consider building a compression or Lofton Leg. If you're in need of a tall platform or if the platform will hold a heavy load, such as with dancing performances, you may consider constructing a compression leg, as seen in Figure 5. The compression or Lofton Leg allows for more stability without the need for a brace. The compression leg has an L-shape and the frame bears the weight, not the top. You start by cutting 1-by-6 pieces to proper length and gluing and screwing them together to form the L-shape. Make sure the joints are flush. You attach the legs to the frame using scrap wood as braces, cut to order as seen in Figure 5. Glue and screw the braces using four or five screws. Test the platform to ensure the legs are attached securely.
9. Attach casters. This will give your platform mobility when set changes are required. It should be noted that platforms with casters should be used individually and not attached to each other, as it can reduce stability due to the caster base protruding out the frame. To attach rubber casters to the bottom of your platform, you will need four No. 10 general-duty rubber casters and four 10-inch square cut pieces of plywood. It is highly recommended to use casters with a side lock brake in order to keep the platform from moving during a performance. Turn the platform upside down, exposing the frame. Align the plywood square base centered on one of the frame joints or corners. Either use a pencil or your imagination to mark a line from the rail on each side of the plywood to the centered point of the joint. Space out and drill four pilot holes along both rails for a total of eight on each base. Make sure you don't place a pilot hole right at the joint, or you will compromise the strength of the joint. Place a coat of wood glue on the surface of the rails and then place the base back down. Using drywall screws, drill the caster base down. Let it dry. Attach the casters using the screws that come with the casters or those appropriate to the exact caster you use.
10. Paint the platform after the glue is dry. This not only keeps it neutral on stage, it prevents the flow of air to the wood if an open flame comes in contact with it such as a cigarette or lighter used during a performance. It is best to paint both the top and bottom. Any color will do, but black seems to be the most useful. Don't forget the edges.
