Switch Pads

Tools Required: Wiss metal snips, Table Saw, Utility knife, Drill, Phillips Screwdriver, Hammer

Click a picture to see a larger view.

1. Cut out all the squares necessary to build the switch pads. Layering of my pads is as follows (from the top):

Lucite (3/32" thick or .093)
Lucite (3/32" thick or .093)
1/4" hardboard
1/8" hardboard

The Lucite panels should be sized to fit, but if you used my dimensions and everything is close to square, they should be exactly 11" x 11". I cut the hardboard panels about 1/16" shy of 11" because it makes it easier to work with. At this point, dry fit all the panels into the pad, mark each and every panel so you can tell where it goes and what the orientation is. This is VERY, VERY important. Notice that I have left the protective covering on the Lucite.

Note: There is no particular reason why I am using 2 pieces of hardboard. A single piece of plywood might work better, as long as it is between 3/8" to 7/16" thick. Technically I think the hardboard is a little cheaper and I like working with it.

2. Cut a small slot (aligned with the wire channel in the base) out of each of the hardboard panels to allow for the wires. I secure them with a 3/4" wood screw in each corner. Placement is important so as to not interfere with the screw that will eventually hold the Lucite down. I drill and countersink these holes 5/8" in from each edge. Make sure you remove the tape that was used to keep the wires in place during construction.

3. After the Lucite has been cut to fit, round off the top edges of all the top pieces with a utility knife by holding it perpendicular to the edge, at a 45 degree angle. Move the knife back and forth several times to scrape the sharp edge off.
Note: I used a table saw with a 60 tooth blade to cut the Lucite. Passing it through slow and steady produces a nice edge. If you don't have a table saw, there are many other techniques listed on the various home built pad websites.

4. Drill a 1/4" hole in each corner of the Lucite panels. I position the hole 1" in from each edge. My technique is to hold the panels tightly together and perfectly aligned while I drill the first hole. Then I put a small piece of 1/4" rubber tubing through this hole while I drill the hole in the opposite corner. I then put a small piece of the tubing in the second hole and then drill the remaining 2 holes. The tubing prevents the 2 pieces of Lucite from shifting and results in perfectly aligned holes which is VERY important.

5. After you drill all 4 holes though both pieces of Lucite, you will want to widen the holes just slightly. The next higher drill bit is too much so I do it by gently wiggling the 1/4" bit inside the holes while drilling. After the holes are done, you may notice some melted Lucite that has re-hardened around the edges of each hole. Make sure you scrape this off with a utility knife, or I find that a countersink bit works well. You might even be able to scrape it off with a fingernail.

6. Line up ALL the Lucite panels back on the pad. Being careful not to move any of them throughout the process, mark the position of each hole with pencil. The down arrow is isolated but all the other panels border one another so I emphasize that you should put all the panels on the pad at the same time, position them exactly where they need to be, with a very small gap between adjacent panels, and mark the holes without moving any of them.

7. Drill a 3/32" or 7/64" pilot hole (at least 1" deep) for each screw. If you have ever drilled a perfectly straight hole in your life, this is the time. These holes will determine if the heads of the corner screws will sit flat on the top of the Lucite panels. If the pilot holes aren't straight, the screws will not go in smoothly, they won't sit flat, and the Lucite will be more susceptible to cracking during use. I drilled a hole though a small block of 3/4" oak with my drill press. I then started each pilot hole as shown in the picture, being careful to only drill about 1/8" deep. Then I used the oak as a jig to complete the hole. By exposing 1 3/4" of the drill bit outside of the chuck, I was also able to drill perfect 1" deep holes. You should also take care to make sure the holes are perfectly centered in the circles you marked in the previous step.

8. I use spray adhesive to attach the bottom piece of sheet metal to the hardboard. I use 26 gauge galvanized sheet metal, cut to 10" x 10" squares. To keep the perfect alignment I have been striving towards in the past few steps, I keep the hardboard secured to the pad and glue the metal in place. The pic shows the pad prepared for this process which can get quite messy with the spray adhesive. You could detach the hardboard panels, and spray them away from the pad, and avoid this taping process but there is always a chance that they will not go back on in exactly the same position. You could also glue the sheet metal before you mount the hardboard to the base but if I did this, the drill jig I used in Step 7 would not sit flat against the hardboard. After I took this picture, I also taped up the wires to avoid getting the adhesive on them as well.

9. Notice I have trimmed the corners of the sheet metal to avoid contact with the screws. I have also drilled a hole in the center of each metal sheet (prior to mounting) to allow me to secure the center of the hardboard to the base. Not sure if this is absolutely necessary but I was paranoid that the centers might ride up a tiny bit after some use. The hole in the sheet metal is just big enough to let the head of the wood screw pass through. As with the corner wood screws, you will need to countersink the hole.

10. Solder the common to each of the bottom pieces of sheet metal. I buff up all the exposed surface of the sheet metal with steel wool to ensure a nice clean contact.

11. A completed bottom half of a switch is shown. Strips of duct tape are placed along the edges of the sheet metal. Then 3/16" thick by 3/8" wide weather-stripping is placed around the edges, on top of the tape. In each corner is a 1 1/2" x 3/4" piece of mouse pad (Fellowes Mouse pad, 3/16" thick, found at Target for $3). I used a hole punch to put a hole in the center of each piece to allow for the screw and tubing used to secure the Lucite.

Update (12/15/2005): The Fellowes mouse pad that Target sells is much thinner now. I found one at Staples for $4.00 that was the right thickness.

12. Here is the top half of the down arrow switch, placed upside down on the center static panel. The wire has been soldered in the corner and duct tape applied. The top half is a 10" x 10" piece of sheet metal with the corners snipped, attached to the underside of the bottom piece of Lucite with spray adhesive. Protective coating was removed from the underside of the Lucite prior to gluing. At this point, you flip this assembly on top of the bottom assembly, making sure the wire is routed to the side of the corner padding (mouse pad). Repeat these steps for each of the remaining 5 switches.

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	1. Cut out all the squares necessary to build the switch pads. Layering of my pads is as follows (from the top): Lucite (3/32" thick or .093) Lucite (3/32" thick or .093) 1/4" hardboard 1/8" hardboard The Lucite panels should be sized to fit, but if you used my dimensions and everything is close to square, they should be exactly 11" x 11". I cut the hardboard panels about 1/16" shy of 11" because it makes it easier to work with. At this point, dry fit all the panels into the pad, mark each and every panel so you can tell where it goes and what the orientation is. This is VERY, VERY important. Notice that I have left the protective covering on the Lucite. Note: There is no particular reason why I am using 2 pieces of hardboard. A single piece of plywood might work better, as long as it is between 3/8" to 7/16" thick. Technically I think the hardboard is a little cheaper and I like working with it.
	2. Cut a small slot (aligned with the wire channel in the base) out of each of the hardboard panels to allow for the wires. I secure them with a 3/4" wood screw in each corner. Placement is important so as to not interfere with the screw that will eventually hold the Lucite down. I drill and countersink these holes 5/8" in from each edge. Make sure you remove the tape that was used to keep the wires in place during construction.
	3. After the Lucite has been cut to fit, round off the top edges of all the top pieces with a utility knife by holding it perpendicular to the edge, at a 45 degree angle. Move the knife back and forth several times to scrape the sharp edge off. Note: I used a table saw with a 60 tooth blade to cut the Lucite. Passing it through slow and steady produces a nice edge. If you don't have a table saw, there are many other techniques listed on the various home built pad websites.
	4. Drill a 1/4" hole in each corner of the Lucite panels. I position the hole 1" in from each edge. My technique is to hold the panels tightly together and perfectly aligned while I drill the first hole. Then I put a small piece of 1/4" rubber tubing through this hole while I drill the hole in the opposite corner. I then put a small piece of the tubing in the second hole and then drill the remaining 2 holes. The tubing prevents the 2 pieces of Lucite from shifting and results in perfectly aligned holes which is VERY important.
	5. After you drill all 4 holes though both pieces of Lucite, you will want to widen the holes just slightly. The next higher drill bit is too much so I do it by gently wiggling the 1/4" bit inside the holes while drilling. After the holes are done, you may notice some melted Lucite that has re-hardened around the edges of each hole. Make sure you scrape this off with a utility knife, or I find that a countersink bit works well. You might even be able to scrape it off with a fingernail.
	6. Line up ALL the Lucite panels back on the pad. Being careful not to move any of them throughout the process, mark the position of each hole with pencil. The down arrow is isolated but all the other panels border one another so I emphasize that you should put all the panels on the pad at the same time, position them exactly where they need to be, with a very small gap between adjacent panels, and mark the holes without moving any of them.
	7. Drill a 3/32" or 7/64" pilot hole (at least 1" deep) for each screw. If you have ever drilled a perfectly straight hole in your life, this is the time. These holes will determine if the heads of the corner screws will sit flat on the top of the Lucite panels. If the pilot holes aren't straight, the screws will not go in smoothly, they won't sit flat, and the Lucite will be more susceptible to cracking during use. I drilled a hole though a small block of 3/4" oak with my drill press. I then started each pilot hole as shown in the picture, being careful to only drill about 1/8" deep. Then I used the oak as a jig to complete the hole. By exposing 1 3/4" of the drill bit outside of the chuck, I was also able to drill perfect 1" deep holes. You should also take care to make sure the holes are perfectly centered in the circles you marked in the previous step.
	8. I use spray adhesive to attach the bottom piece of sheet metal to the hardboard. I use 26 gauge galvanized sheet metal, cut to 10" x 10" squares. To keep the perfect alignment I have been striving towards in the past few steps, I keep the hardboard secured to the pad and glue the metal in place. The pic shows the pad prepared for this process which can get quite messy with the spray adhesive. You could detach the hardboard panels, and spray them away from the pad, and avoid this taping process but there is always a chance that they will not go back on in exactly the same position. You could also glue the sheet metal before you mount the hardboard to the base but if I did this, the drill jig I used in Step 7 would not sit flat against the hardboard. After I took this picture, I also taped up the wires to avoid getting the adhesive on them as well.
	9. Notice I have trimmed the corners of the sheet metal to avoid contact with the screws. I have also drilled a hole in the center of each metal sheet (prior to mounting) to allow me to secure the center of the hardboard to the base. Not sure if this is absolutely necessary but I was paranoid that the centers might ride up a tiny bit after some use. The hole in the sheet metal is just big enough to let the head of the wood screw pass through. As with the corner wood screws, you will need to countersink the hole.
	10. Solder the common to each of the bottom pieces of sheet metal. I buff up all the exposed surface of the sheet metal with steel wool to ensure a nice clean contact.
	11. A completed bottom half of a switch is shown. Strips of duct tape are placed along the edges of the sheet metal. Then 3/16" thick by 3/8" wide weather-stripping is placed around the edges, on top of the tape. In each corner is a 1 1/2" x 3/4" piece of mouse pad (Fellowes Mouse pad, 3/16" thick, found at Target for $3). I used a hole punch to put a hole in the center of each piece to allow for the screw and tubing used to secure the Lucite. Update (12/15/2005): The Fellowes mouse pad that Target sells is much thinner now. I found one at Staples for $4.00 that was the right thickness.
	12. Here is the top half of the down arrow switch, placed upside down on the center static panel. The wire has been soldered in the corner and duct tape applied. The top half is a 10" x 10" piece of sheet metal with the corners snipped, attached to the underside of the bottom piece of Lucite with spray adhesive. Protective coating was removed from the underside of the Lucite prior to gluing. At this point, you flip this assembly on top of the bottom assembly, making sure the wire is routed to the side of the corner padding (mouse pad). Repeat these steps for each of the remaining 5 switches.