A bolster on a knife is the area that connects the knife blade to the handle. On a forged knife, the bolster adds weight to the handle end of the knife and acts as a counter weight to the heavy bladed end. The bolster can also act as a grip guard on a knife, protecting the cutting hand. Adding a bolster to a knife handle can give the knife a better balance and make it easier to use. Adding a bolster requires two pieces of steel, to be attached to each side of the blade.
Plan the knife handle design around the bolster. While many high-quality knives are forged with the blade, bolster, and tang as one piece, many knifes include a bolster riveted to the blade and tang. These bolster are riveted to the tang to increase balance and sturdiness.
Cut the bolster material, usually stainless steel, into sheets slightly larger than the design calls for. Clamp the blade flat to a table, and drill two parallel rivet holes in the centre area of the bolster using 11/64 size or similar drill bit. Superglue one side of the bolster to the knife blade and clamp it tightly until it is dried.
Turn the knife blade over and using the parallel rivet holes as a guide drill through the superglued bolster, creating rivet holes through the bolster. Remove any burrs and metal shavings from the knife.
Superglue the second bolster to the knife handle and clamp until it is dry. Turn the knife over, and drill rivet holes through the first bolster into the newly applied bolster. Remove any burrs and shavings from the knife and clamp it so that you have access to the bolster pieces. Use a pin punch to remove the glued bolsters from the blade.
Mark the excess areas of the bolster, and mill the bolster pieces into the proper shape. Mill any extra height off the bolster and sand any remaining glue and burrs from the pieces. Reapply the pieces to the tang and rivet. Attach any other handle pieces to the tang to complete the knife.
Use caution when using powertools and sharp knives.