The REAL Demo Knife

by Ken Cook

During my research on the background of the knife I fondly remembered as the “Demo Knife” I learned from Tom Williams, Camillus Knives Company Historian that there was at one time a project to create a “real” Demolitions Knife.



Although I was unable to find a better picture or drawing, I offer these highly detailed and descriptive excerpts from the original documents transcribed as they were originally presented in the document titled below. Although the stiff and formal prose typical of all military documents makes for some very dry reading, I believe the reader will find these excerpts as fascinating as I did.



Technical Report # 68-15

 Knife, Demolition

 Final Report


U.S. Army

Limited War Laboratory

Aberdeen Proving Grounds

Oct 1968


by Frederick M. Drake

Environment and Survival Branch





A compact, lightweight demolition knife was developed to fulfill a need for a composite demolition tool which would retain the functional capability of the items it would replace. The components of this knife include a cutting blade, two screwdrivers, a centimeter scale for measuring fuse, and charges, demolition cap crimper, wire and fuse cutter, demolition cap setter, sewing awl, and wire stripper.


CONUS tests of the demolition knife were conducted by Special Forces Engineers and E.O.D. units. Results of the tests indicated a material weakness in the knife blade and cap setter, however test personnel recommended the demolition knife be sent to RVN for field evaluation.






The original knife development was intended to provide an all-purpose knife to the individual soldier. Referred to as a clasp knife for Special Forces, the initial prototype was a folding pocket knife based upon the design of the Alaskan Guide Knife. In addition to possible use as an in-fighting knife, it would replace the general purpose hunting, rigging (parachute), pocket, Signal Corps knife, and would have the added capability for demolition work.


Prototypes of the knife were furnished to the U.S. Army John F. Kennedy Center for Special Warfare for examination and comments in November 1964. The comments were mostly favorable, particularly on the demolition functions, however, general interest was not forthcoming and the development was discontinued.


During 967 interest in a knife was revived and the present development was initiated. However, based upon the recommendations of the U.S. Army Special Warfare School Demolition Committee, the scope of work was changed from the all-purpose knife concept to the development of a knife specifically for demolition operations. Design considerations resulted in a knife which offers a maximum number of operational tools required for field demolitions.


Design and Materials of Construction


The overall configuration of the knife retains the general shape of the Alaskan Guide Knife. To permit machine production however, the non-uniform curvature of the Alaskan knife was converted to standard radii. This is of particular importance in fabricating the handles which are aluminum with a Martin hard coated finish (black color) . In addition to imparting a black non-reflective finish to the knife, Martin hard coating (Rockwell C-57) resists scratching and chipping of the handles.


Design of the blade considered six separate operational functions. These included cap crimping, fuse cutting, cutting or shaping demolition charges, wire cutting, general light cutting operations and measurement of fuse or charge lengths with the engraved scale on the blade (10 centimeter length). The back of the blade is wider than a normal blade to allow more hand pressure to be applied in the crimping and cutting operation. The blade tip is blunt to prevent hand cuts or nicks and the blade is not spring loaded so that cutting and particularly crimping can be accomplished without the danger of the blade snapping shut prematurely.


Beryllium copper (alloy 25, ½ hard) was used to fabricate the knife blade based upon its “non-sparking” properties. This would preclude the possibility of a “spark” prematurely setting off a cap or demolition charge. The most critical area here, of course, is the crimping operation.


In choosing beryllium copper for the knife blade, appreciable metal hardness was sacrificed. The average hardness of the blade is Rockwell C-35 which is sufficient to perform the necessary demolition operations, but requires frequent sharpening. Any future development would consider the use of stainless or high carbon steel for the blade with a beryllium copper insert for crimping.


When the blade is in the full-open position, it is held by a beryllium copper lock. This blade lock has appropriately spaced cut-out sections to receive the cap and fuse for the crimping and fuse cutting operations. Dimensionally, the blade is 4 ½  inches long, approximately 1 inch wide at the base and tapering to the blunt end, and .09 inches thick at the back of the blade.


The cap setter (punch) was designed to form a hole in demolition charges, large enough to receive both the standard electric and non-electric blasting cap. It is 2 ¾ inches long overall, with a ¾ inch flat tapered end to form a small screwdriver and also act as a point to penetrate the demolitions. The cap setter is machined from beryllium copper alloy 33-25 (½ hard, square stock) with the corners rounded to give a diagonal diameter of 0.250 inches. This diameter is sufficient to receive the cap but inasmuch as the effective length at this diameter is only 2 inches, difficulty is experienced in seating the cap flush with the demolition. A small thread hole is also incorporated in the tapered end of the punch which could be used for rough sewing, although it is believed this would have only limited use.


A screwdriver constructed of spring-steel was designed to handle larger sized screws, and built into the screwdriver blade is a sharpened notch for stripping covered demolition wire. The blade is slightly over 1 inch long, is .023 inches thick, and it is capable of withstanding considerable pressure in removing large or corroded screws. For wire stripping, the knife is held in the right hand, and with a little practice, no trouble is experienced stripping the various wires used, including WD-1. The blade is held in the open position by a beryllium copper lock.


The latch for the knife and screwdriver blade is fabricated from spring-steel, specifically treated to resist corrosion. Both the spacer and blade stop are brass, all rivets are nickel-sliver alloy and the “D” ring is beryllium copper. Compatible metals were used in the overall fabrication of the demolition knife to minimize galvanic corrosion.


When fully opened, the demolition knife is 9.88 inches long and when closed, it is 5.49 inches long. The knife weighs seven ounces.




Tests were conducted in CONUS by Special Forces (Fort Bragg), Army Engineers (Fort Belvoir) and E.O.D. personnel (Picatinny Arsenal).  Results of these tests indicated that beryllium copper used in the knife blade and cap setter was softer than anticipated. The blade required frequent sharpening, the screwdriver on the cap setter chipped or rounded off, and in several instances, the cap setter broke off at the base. In the follow up meeting at Fort. Belvoir, methods of carrying the knife were discussed and it was recommended by the test personnel that a means of attaching the knife to the belt be provided.  This could be accomplished either in a pouch or by a snap swivel on the knife “D” ring. The decision was made to provide a split ring and snap swivel as shown in Figure 1, Knife, Demolition. Appendix A includes a copy of the recapitulation of the test results and a memorandum on the Fort Belvoir meeting.


A letter was received from HQ USARV 12 may 1968, requesting 150 demolition knives for evaluation. The knives were shipped to RVN, 8 August 1968.




I would like to extend my very sincere thanks and appreciation to Camillus Company Historian Tom Williams, without who’s eager, timely, and very expert assistance this article would not have been nearly as interesting, complete, or accurate.




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