When I started in construction, I pilfered a bunch of tools from my father, among them his old fixed-blade utility knife. After about six months, the blade made its way through the bottom of my leather tool pouch and into my leg. (I guess I deserved it for raiding my father's tools without permission.) Eighteen stitches later I bought my first retractable knife and now I only cut myself if I do something careless.
Today, retractable utility knives are a staple in almost everybody's tool pouch. I use mine more frequently than my hammer–sharpening pencils; cutting shingles, foam board sheathing and vinyl siding; back-cutting miters; coping small moldings; and, of course, cutting drywall. I also use the knife body as a wedge and sometimes as a temporary shim. I'd be lost without it.
I tested eight traditional retractable-blade utility knives–the Great Neck 80024 Speed Feed, Husky 82068 Autoblade, Hyde MaxxGrip 42081, Irwin 2082200 ProTouch, Klein 44107 Kurve, Lenox Gold SSRK1, Olympia Turboknife II 33-131, and Stanley 10-788 QuickChange–and three knives with non-standard designs: Olfa 9115, Sheffield 12113, and Tajima GRI LC0660. I tossed each one into my tool pouch and gave them a thorough workout on site and in the shop. I examined blade retraction, blade change, and blade storage, and then evaluated them subjectively for balance and feel.
Blade Action. A utility knife isn't much good if the blade is hard to extend or retract. In fact, it's downright annoying. The good news is that all the knives in this test have good blade action out of the box. All the traditional knives have a top-mounted thumb button with three blade-extension detent positions. Most of the models got sticky after a couple days cutting drywall, but a quick shot of spray silicone lube up the nose fixed that. The detents on all knives locked securely.
Blade Slop. One of the drawbacks to retractable knives is blade slop: When fully extended the blade wobbles a little up-and-down and side-to-side, a fact I just expect with traditional utility knives. The knives in this test all had the same slop range. I still like a fixed-blade model for precision operations where a sloppy blade is frustrating, like cutting cardboard templates. The Tajima and Olfa both have long blade guides that support the blades better than the traditional knives for much more control at the blade tip, which I like for those exacting jobs. While the Sheffield knife isn't retractable, it is foldable so you get the safety of a housed blade and the stiffness of a fixed one, which is good for some tasks.
Blade Retention. I punished the knives by cutting deep into 2-by to make sure the blades all held tight at all three detent positions. Only the Great Neck blade guide let go of the blade when it was fully extended, but it took a good bit of force to pull the blade free.
Blade Change & Storage
I thought I'd found Nirvana when I bought my first knife that didn't require disassembling the body to change a blade. All the models in this group have tool-free blade-changing features, employing several smart designs.
Open Shell. The Klein Kurve has the simplest system in the group: The tail cap rotates 90 degrees so the left side of the shell can be removed, exposing the blade storage and blade slide. A body-mounted magnet keeps the blade and blade slide from falling out–smart thinking for blade changes in awkward places. The extra blades rattle loose in a compartment inside the tool body, however, which can cause dulling. Hyde's rear-hinging body opens by sliding a side-mounted button. The blade slide has a magnet to secure the blade, but the slide itself is loose and can fall out. Magnets to secure the slide would be a good improvement. Extra blades ride upside down and have two springs that keep them from rattling around and dulling.
Quick Reverse and Open Shell. The Irwin and Lenox knives each have a quick blade change feature that works like reverse on a stick shift: press the fully extended thumb button down and to the right and the blade releases; you can then remove it and turn it around to the fresh side without opening the knife. This is a real time saver. Changing a blade requires opening the tool body to access the blade storage; pressing a side button unlocks the spring-loaded body, similar to the Hyde. The blades are secured in a spring steel clip to prevent edge wear; however, it was tricky to extract a single blade from the clip. I ended up popping the whole load out to get one and stashing the rest back in.
The blade slides on the Irwin and Lenox are locked into guide slots so the mechanisms won't drop out of the bodies–smart. And, a magnet holds the blade fast during the process. Lenox has a reinforcing nose collar that prevents fresh blades from being dropped directly into the slide. Instead, you have to close the tool and slide the fresh blade in through the nose. This design works quite well.
Drop-Down. Stanley stores extra blades in a dropping plastic belly. Even though the blades sit loose inside, the edges don't wear. Fully extended blades can be reversed or replaced by pressing the button on the left side and withdrawing the blade, which works well.
Automatic Reloads. Great Neck, Olympia, and Husky go one step further to ease blade changes–automatic reloading. The action to reverse a blade is the same as with the Irwin and Lenox: You fully extend the blade, press the button to the right, and withdraw the blade to reverse it. Changing to a fresh blade is fun, just discard the old one and retract the thumb slide. A new blade automatically loads without opening up the body.
All three knives have doors on the left side that can be loaded with seven to 10 blades. The Olympia and Husky plastic doors are hinged. Be sure to hold the button back when closing them to ensure a positive lock and to reduce wear on the plastic strike. The Great Neck's door relies on tabs rather than a hinge and comes free from the knife body for re-loading. Be careful not to drop the door when reloading blades. I was skeptical of the reliability of the automatic loading function of these three knives, but they all held up well. For users who like the freedom of one-handed reloads in a flash, the Great Neck, Husky, or Olympia is the way to go. I don't mind manual reloads, but I'm also the same guy who refuses to buy a truck with an automatic transmission.
Snap-Off. Tajima blade changes are a snap–literally. When you need a fresh edge, just break off the spent tip at the next perforation. This isn't your kitchen-drawer snap-blade knife: The 1-inch-wide blade is hard, stiff, and sharp–and works great for all jobsite cutting. Loading a fresh seven-section blade is easy: just slide the blade lock out of the rear of the body and reload. And, if you need a lot of blade exposed–say for cutting rigid foam or batt insulation–the blade extends 4 full inches, exposing a lot of cutting edge. Very handy.
Remove and Replace. Olfa's blade looks similar to a regular utility knife but is longer and more narrow. Reversing and replacing blades is accomplished by removing the rear retainer and sliding the blade guide out. It takes some practice to handle three parts and a blade or two during the process. The Olfa has no onboard storage for extra blades, but the blade does have five detents, which can be helpful.
Fold-Up. The Sheffield has no blade storage either, but blade changes are simple: Unfold the knife and unhinge the retaining clip and the blade chamber door, then insert a new blade.