Klingon Knives
There are many kinds of Klingon knives, but due to the availability of images to work from, I have focused on the d'k tahg. As I discover additional images this section will grow.
Klingon d'k tahg knives vary frequently, this may be due to designs based on the House served, Fleet served, the rank, the family, or personal preference of the individual. I am aware of no standard for these knives.
Some of the differences are subtle, such as changes in the shape of the blood line, others are drastic, such as changes in the shape of the handle.
Generally speaking, all the knives share this in common, they are approx. 13 - 16 inches (33.02 - 40.64 cm) long, the blades are approx. 3/16 of an inch ( 4.7625 mm) thick and 2 inches (5.08 cm) wide at the widest point. From my examination of an actual prop, and discussions with custom knife collectors, the I believe that the main portion of the handle is 7/8 of an inch (22.225 mm) thick. Finger grips and hilt add an additional 1/8 of an inch (3.175 mm) to the thickness/side, and any other details add no more than an additional 1/4 of an inch (6.35 mm) to the thickness/side. So, overall, the knife would be 1-1/8 inches (2.8575 cm) thick, and 1-5/8 inch (4.1275 cm) at its widest point.
NOTES: Images are not to scale, the d'k tahgs and the mevak were custom made for Paramount (except for figure 4), while Figures 5, and 6 are commercially available.
Figure 1 represents the first d'k tahg introduced in "Star Trek III: The Search for Spock". Used to kill David Marcus. The knife had a rust colored hilt and pommel, with a black handle (including finger grips).
Length: approx. 14 inches
Side blades: Opposing sides of main blade
Trigger: Finger activated, inline with main blade
Original Image Source: "The Star Trek Encyclopedia, revised edition"
Length: approx. 16 inches
Side Blades: Opposing sides of main blade
Trigger: Thumb activated, along the side of the main blade
Original Image Source: Online
Length: approx. 14 inches
Side blades: Opposing sides of main blade
Trigger: finger activated, inline with main blade
Original Image Source: "Star Trek: The Continuing Mission"
Length: 13 inches
Side Blades: same side of main blade
Trigger: Thumb activated, along the side of the main blade
Original Image Source: Online
Length: approx. 14 inches
Original Image Source: "Sci-Fi & Fantasy Models International #37"
Figure 6 is Gil Hibben's "Raptor" knife and is making inroads into Klingon personal weapons, a mirror universe's Jadzia Dax used it to threaten Captain Sisko ("Through the Looking Glass" [DS9]. I spied what I believe to be the knife among Worf's collection of blades (only the handle is recognizable) in "Afterimage" [DS9]. Further evidence of the use of this particular knife is offered in Blade Magazine's January 1999 issue, in an article that covers Gil Hibben, United Cutlery, and Star Trek's involvement with each other.
Length: 13-7/8 inches
Original Image Source: Online
Length: 12-3/8+ inches
Side Blades: N/A
Trigger: N/A
Original Image Source: Online