Blade

• 1). Choose the steel to use for your blade. Use the blade from an old knife in your house or buy one at a thrift shop, junk shop or market. Often, an affordable option still needs some grinding, shaping and polishing. In such cases, make a guide by drawing a full-size knife pattern on paper. Grip it as if it were steel so you can get the initial feel and determine if your pattern is too wide or narrow, depending on how you hold the paper pattern. For symmetrical designs, fold the paper lengthwise and outline half of the design on paper.
  
  
• 2). Cut and unfold the paper pattern; then temporarily adhere it to each blade you plan to shape and polish, using masking tape or a similar adhesive.
  
  
• 3). Make two identical blades to attach together using a rivet, and one of them to connect to the handle, which will allow you to fold your homemade knife accordingly. Cut the steel using a cutting band saw. Alternatively, use a hacksaw, but this can take a little more time.
  
  
• 4). Use a grinder to better outline the shape of each blade, following the paper pattern you made. For minimal shaping, polishing and rust removal, use sandpaper and a file. Clean up all scales and scratches with the sandpaper. Although it's slower to work with sandpaper and file than using a grinder, the slower work provides better accuracy and fit. Cut, clean and shape each blade until you have completely shiny surfaces. Remove the paper pattern from each blade.
  
  
• 5). Drill two holes into the top and bottom of the blade for the handle area; the 1/2-inch rivets will hold together the blade and handle. Ideally, place the hole pieces somewhere in the middle of the vertical blade on each end, about 3/8 inch from the end. Prior to drilling, anneal the steel's drill points for about 10 to 15 minutes using a small propane torch to help soften the steel for drilling.
  
  
• 6). Join the two blades together using a male-female type pivot screw.
  
  

Handle, Back Spacer and Lock

• 1). Prepare the wooden handle and the hinge to make the blade fold. Make your handle according to the shape you want for a good grip. Alternatively, model it using another knife's grip or by testing a cardboard or paper for the right grip to suit you. As a folding knife, the shape of the handle must correspond with the shape of the folded blade.
  
  
• 2). Drill two matching holes into the top and bottom of the handle area.
  
  
• 3). Make a back spacer, ground in a shape that conforms to the blade edge when the knife is in a closed position, by drilling a back spacer and countersinking the holes on one side of its frame, then tapping on the other. Drill the holes at about 0.75- to 1-inch away from each end. Since the back spacer must attach itself into both the handle and the part of the blade meant for attachment to the handle, make exact drills for your pass holes.
  
  
• 4). Fit the blade, handle and back spacer together to check if any parts don't work well. Ensure that all placements conform with the shape of the blade and the location of the drilled holes. The blade must work freely, so have a pivot nut that is slowly ground down to the assembly, then tighten down the pivot screw.
  
  
• 5). Cut a lock notch for a lockbar, the part of the lock within the handle area to rest against the notch on the blade to hold it securely. The shape and size of the lockbar depend on the size of your blade. Ideally, cut about 1/2 inch at one side end of the blade to place on the assembly of the blade, handle and back spacer.
  
  

Final Fitting and Assembly

• 1). Assemble the blade, handle and back spacer together using screws placed on the drilled holes for testing. The entire assembly must secure and lock the blade, whether in use or in a folded position for safety.
  
  
• 2). Disassemble to attach a pocket clip to rest on the lockbar to serve as extra support for the lock.
  
  
• 3). Drill another hole into the lockbar to hold the knife blade shut when not in use. Drill a matching hole into the part of the blade opposite the one for attachment to the handle (the actual blade of the homemade folding knife).
  
  
• 4). Attach the thumbstud into the hole using a shortened threaded shaft screwed into both the thumbstud and blade.
  
  
• 5). Assemble the final piece.