Columbia River Knife and Tool's Nirk 5180 Brushed Frame Satin Razor Edge Knife
Columbia River Kinife and Tool's Nirk 5180.  The innovation is Glenn's use of a single sheet of stamped and folded stainless steel to serve as the folder frame, back spacer, spring and lock, resulting in a solid lockback folder. The geometry of the cutout areas is critical, carefully calculated to provide just the right spring action when the rear of the spine is pressed.  At the front of the frame, the lock tab mates with a notch in the blade to provide safe lockup. The tighter the grip on the handle, the tighter the lockup, making this an exceptionally safe design. It is very difficult, if not impossible, to accidentally release the lock, and it is very, very strong.  When the blade is closed, the same lock tab ramps over a rounded detent to hold the blade in the closed position.  The high-carbon stainless steel blade is a utilitarian drop point shape with a deep belly, high hollow ground for easy cutting, and with a swedged top edge to aid penetration. It is a hefty 0.131" thick. The blade can be opened with either hand using the oval thumb hole.  The 5180 sport and work model has a high satin blade finish, brushed frame and Razor-Sharp cutting edge.  The NIRK has a stainless steel pocket/gear clip.  There you have it: a simple, flat, almost indestructible folder. All you need to do is oil and sharpen it occasionally and you have a friend for life. It is priced so you can afford several: one for the toolbox, one for the backpack, one for the truck, one for the boat, one for the survival kit.