The integral bolster design that is sometimes seen on knives is the thick area at the transition point between the blade and handle. Part of the handle itself, it tapers from the blade thickness seamlessly to the handle thickness. This protects the handle material from wear, reduces seams and connection points and leads to a much sturdier blade. Most handmade knives do not have integral bolsters because they must be forged to shape and it is an advanced technique which is difficult and time consuming. Admittedly it is more efficient to cut a blade out of thin steel and add a handle with no bolster which I do often. The blade works just as well but there is something about the flow of an integral bolster knife that keeps me forging them.
Factory production chef knives are much more likely to have that integral bolster. The blades are stamped by computer controlled machines with perfect precision and there is no human hand work involved in the process. This does not mean production knives can’t be great knives, it is just a different thing. When I make an integral blade, I start with steel in round form between 1” and 1.5” or make a billet of damascus first, then forge the blade. Conceptually it is simple. I need to forge the blade and tang while keeping the bolster area thick. This does not happen easily. It is very common for the blade to take on a different shape than one intends when forging a knife like this. It also requires moving much more steel than a typical knife and the spine and heel are difficult to properly position.
Forging steel is like working with a tube of toothpaste - once it goes out the end, it won’t go back in. If too much of the steel elongates, there is no way to shorten it. Thick pieces of steel can be shortened by a process called “upsetting” but this cannot be done with steel at the thickness of a knife. I must use my previous experience to preform the workpiece so that the right amount of steel is loaded where it needs to be. The two most critical points on these knives are the heel position and the angle of the bolster and tang relative to the cutting edge angle. There is a delicate balance on each knife that has to be carefully adjusted by hand. The important point about the blade to bolster transition area is that the heel of the knife should drop away from the handle immediately without a wide area of steel that is neither handle nor blade. The tang and bolster angle should flow well with the blade design but most importantly on a chef knife, the handle should be high enough to give the knuckles of the user clearance above the cutting surface.
Damascus steel is especially nice on an integral bolster because the pattern flows from the blade into the handle seamlessly, showing the work of the forging process. The distortion that occurs from stretching the steel in the transition area is what creates that unique flow. An added bolster or guard is a difficult technique as well but the integral has a very unique beauty. For more information, check out BLADE’S Guide to Buying Knives by Jason Fry which features one of my integral chef knives in the color photo section.