How to Make a Lockback Knife

How to Make a Lockback Knife
A lockback knife is a folding knife with a blade that fits inside the handle. The lockback knife is distinctive in that the handle also has a locking mechanism that holds the blade in the fully extended position. The mechanism may be disengaged to return the blade to the closed position by pressing a lever on the back of the blade's handle.
 

Instructions

Difficulty: Challenging

Create a Template

Things You’ll Need:
  • Graph paper
  • Pencil
  • Cardboard
  • Xacto knife
  • Straight pins (sewing)
  • Sharpee marker
  • Stainless-steel metal stock for blade and spring
  • Brass metal stock for sides
  • Pins for riveting the blade together
  • Metal cutting saw
  • Metal working file
  • Metal grinder
  • Drill with bits for both metal and wood
  • Slitting disk for the drill
  • Wood, bone or horn for handles
  • Heat-treating furnace
  • Lead solder
  • Soldering gun
  • Brass bolster
  • Scale material (thin brass)
  • Epoxy
  • Emory paper
 
Step 1
Sketch out your knife design to scale on graph paper; show the blade in both opened and closed positions. The handle and open blade should form a straight line, and the length of the knife tang (the metal part that extends into the handle) should be the same as the length of the handle. Sketch a circle inside the tang and place a dot at the center of this circle. This will be the blade's pivot point. Make a dotted line across the back of the handle to show the blade's end point when closed. The handle should be longer than this end point to make room for the lockback spring.
Step 2
Draw the position of the spring inside the knife. The middle pin for the spring should be two-thirds of the distance from the tang to the end of the knife. The spring should be three millimeters deep at the tang end, and six millimeters deep at the middle pin. The end of the spring should be large enough to give the knife stability and to be anchored by the end hole.
Step 3
Trace the parts of your knife onto a piece of cardboard that is the same thickness as your metal, and carefully cut the parts with an Xacto knife. Mark the spring and pins on your templates. The parts of your knife that you will make into a template include the spring, blade with tang and the handle.
Step 4
Assemble the template, using straight pins used for sewing to hold the template together at the assembly points. Then open and close the knife blade to ensure that the knife will fit together correctly when it has been assembled.

Make the Knife

Step 1
Transfer your pattern from your template to the surface of your knife metal using a Sharpie marker. Cut out the metal parts, but leave extra space along the edges of the spring and the tang so that you can grind them down for a more accurate fit.
Step 2
Drill the holes for the pins. Place the spring and the blade against your template, and carefully file the edges for a smooth fit. Ensure that the spring fits against the back square of the tang when open, and the kick of the tang when closed.
Step 3
Heat-treat the spring in the furnace, and then check the fit against the blade to ensure that the spring did not warp in the process. Gently round the corners of the tang with the file until the blade opens and closes smoothly against the spring.
Step 4
Transfer the pattern of the sides to the brass metal stock with the marker, and then cut out the sides from the metal. Assemble the knife within the sides and test the opening and closing action. If required, take the knife apart and adjust the shape of the sides, knife and spring.
Step 5
Cut the scale material from thin brass to match the shape of the sides. This will go on the outside of the knife's sides. Assemble all of the metal parts, using pins to hold the assembly together. Solder the bolster to the exterior of the scale over the tang.
Step 6
Cut bone, horn or wood handles to the same shape as your brass sides. Epoxy these in place. Finish the knife by polishing the blade with Emory paper, sharpening it with a whetstone and lubricating the joints.
 

Tips & Warnings

 
To shorten the knife-making process, you can purchase a knife making kit with the parts of the knife already cut out and ready to be assembled.

Resources

Article Written By Tracy Morris

Tracy Morris has been a freelance writer since 2000. She has published novels and numerous online articles. Her work has appeared in national magazines and newspapers including "Ferrets," "CatFancy," "Lexington Herald Leader" and "The Tulsa World." She holds a Bachelor of Arts in journalism from the University of Arkansas.

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