Here's how I made a footswitch for my belt sander.

Awhile back I made a stand for my belt sander (see the last photo). To start the unit I had to reach around and push the trigger with one hand and push the lock button with the other hand. Not very safe since it placed my chin close to the rotating belt. Like a monkey, I thought using my feet may be safer. I needed a footswitch!

I tried eBay but decided to make something myself. I searched Instructables and found these two entries.
Dremel Foot Switch
DIY Power bar
I basically combined the two. Thanks for the ideas guys!

This is an easy Instructable. You can put this together with basic tools: screwdrivers, pliers, drill, hot glue gun, superglue, soldering iron, jaws of life. After you get all the parts, it should take about an hour to assemble. It took me longer to write this Instructable than it did to make this thing. :-)

Step 1: Parts and Coin

Plastic 2 Gang J box - OSH $4.69
1/2" End Cap - OSH $0.35
Rubber Feet - OSH $2.19
Appliance Replacement Power Cord - OSH $8.69
Wall Switch - OSH $4.19
2 Gang Wallplate - Weird Stuff $1.00
Receptacle - Weird Stuff $0.50
2 Acrylic 1" dia. solid domes - Tap Plastic $1.50

(Not Shown)
3 pieces of wire, 5.5" long 14-18 awg
Zip Tie
Electrical Tape
Flux Capacitor

Step 2: Make a Trash Strain Relief

Let me just say this, do the right thing and buy a proper Heyco strain relief. I threw this quickly together for the sake of time. While it works for now, it may become hazardous with usage.

Obligatory Warning: You may be risking injury or property loss by using this trash mod. But here's what I did:

Drill a hole in the cap the same dia. as the power cord.
Insert the power cord into the cap then mount it to the box.
Set it to the proper length inside the box giving yourself enough wire.
Pull the cap and cord back out and measure the length of the cord from the end to the bottom of the cap.
Pull more length of cord through and put a zip tie to the length you measured.
Clip off the excess zip tie and pull back the cord in the cap until the zip tie bottoms out in the cap.
Partially fill the cap with hot glue until the zip tie is fully covered.
Put the cap/cord back into the J Box tightly securing it with glue.

Step 3: Get Wired!

I decided to keep one receptacle unswitched and the other switched. I understand this is called a "half switched receptacle." I planned on using the switched receptacle for the belt sander and the unswitched for a lamp that I leave on. Here's a link to a diagram of how to wire up a half switched receptacle.
Half Switched

Per the diagram, you need to break off a tab on the brass side of the receptacle.
Grab the tab with some pliers and bend it back and forth until it breaks off.

Next find some scrap wire, 14-18 AWG. You'll need three pieces about 5.5 inches long.
Strip the ends off. There's a strip gauge on the back of the receptacle that shows you how much insulation to remove.

Solder only the tips of the multistrand wire. It will eliminate loose strands. Loose strands can cause a short. With your pliers, form a hook shape on the end of the wire.

Hook the wire into the screw terminal wrapping it in a clockwise direction around the screw. You don't want the hooked wire facing counterclockwise because it will force the wire out of the terminal as you tighten it. Thank Mr. Crowe, my High School shop teacher for that bit of advice.

Per the above diagram, finish wiring everything.

Something Mr. Crowe didn't teach me is an extra precaution I like to use. After you're through wiring all the connections, wrap electrical tape around the bodies of the switch and receptacle.
This is just an added precaution just in case a wire comes loose.

Before screwing down the receptacle and switch into the J Box, remove the small black screw retainers first. You'll need the receptacle and switch to fit flush.

Lastly, remember to wire up the green ground wire from the cord to the receptacle and switch.

Step 4: It's Banana Time!

Add the self adhesive rubber feet.

Superglue on the acrylic domes to the switch. I found these premade at Tap Plastics.
These are needed to make it easier to use the switch with your feet.

Add some P-Touch labels and you are done! Get a beer and banana.

Final Obligatory Warning: These parts are indoor rated and not intended for outdoor use.
No telling what long term affects these parts will have in a dusty or dirty environment. In addition, these parts are rated 120 volts, 15 amps. Be careful not to overload these parts especially with motor operated appliances...like a belt sander.