Editing Utility knife (section)

==Design==
Utility knives may use fixed, folding, or retractable or replaceable blades, and come in a wide variety of lengths and styles suited to the particular set of tasks they are designed to perform.  Thus, an outdoors utility knife suited for camping or hunting might use a broad {{convert|75|to(-)|130|mm|in|sigfig=1}} fixed blade, while a utility knife designed for the construction industry might feature a replaceable utility blade for cutting packaging, cutting shingles, marking cut lines, or scraping paint.

===Fixed blade utility knife===
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[[File:X-Acto-knife.jpg|thumb|right|Fixed-blade [[X-Acto]] knife for handicrafts and model making]]

Large fixed-blade utility knives are most often employed in an outdoors context, such as fishing, camping, or hunting.  Outdoor utility knives typically feature sturdy blades from {{convert|100|to(-)|150|mm|in|sigfig=1}} in length, with edge geometry designed to resist chipping and breakage.

The term "utility knife" may also refer to small fixed-blade knives used for crafts, model-making and other artisanal projects.  These small knives feature light-duty blades best suited for cutting thin, lightweight materials.  The small, thin blade and specialized handle permit cuts requiring a high degree of precision and control.

===Retractable utility knife===
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Construction utility knives, typically made from [[die casting|die-cast metal]] or robust [[molding (process)|molded plastic]], have retractable and replaceable blades. The user of the knife can adjust the distance that the blade extends from the handle. For example, cutting the tape that seals a package without damaging the contents requires the blade to be extended slightly, while cutting the cardboard box requires the blade to be extended further forward.

A utility blade that has become dull can be reversed or replaced with a new one. Spare or used utility blades can be stored in the handle of some utility knife models and can be accessed by removing a bolt and opening the handle. There are also models of utility knives equipped with a quick-change feature that allows blades to be replaced without additional tools. Retractable utility knives are commonly used in construction, crafting, utility and warehouse work.

==== Utility knife blades ====
It is the material to be cut that determines which type of utility blade is required to be installed in the utility knife. In standard knives can be installed different forms of blades, varying and expanding the functionality of the knife. So the standard and universal option for craft and construction work is considered a trapezoidal blade, which is suitable for [[drywall]], [[cardboard]], cutting [[Flooring|flooring covering]] materials, and more. There are also specialized blades for cutting [[Bituminous waterproofing|roofing felt]], [[linoleum]], [[Fitted carpet|carpeting]], [[foam]], [[Building insulation material|insulation]] and other building materials.

Standard blade types include:

* [[Trapezoid]]al blade: the sturdy blade is sharpened on both sides and has 2 pointed and sharp tips, so it can be turned over and reused. The most common replacement blade, suitable for universal use.
* [[Hook]] blade: a trapezoid-shaped blade that has hooks instead of pointed tips. Hook utility blades are suitable for cutting with a pulling motion such materials as roofing felt, linoleum, carpeting.
* Concave blade: similar to a hook blade, but has a more elongated hook on only one side. Suitable for cutting out details and forming shapes.<ref>{{Cite web |date=2023-09-04 |title=[GUIDE] 8 Types of Utility Blades |url=https://www.sollex.com/blog/post/8-types-of-utility-blades-guide |access-date=2025-02-25 |website=Sollex |language=en}}</ref>

==== Snap-off utility knife ====
Another type of utility knife is a snap-off utility knife that contains a long, segmented blade that slides out from it. As the endmost edge becomes dull, it can be broken off the remaining blade, exposing the next section, which is sharp and ready for use. The snapping is best accomplished with a blade snapper that is often built-in, or a pair of pliers, and the break occurs at the score lines, where the metal is thinnest. When all of the individual segments are used, the knife may be thrown away, or, more often, refilled with a replacement blade. 

This design was introduced by Japanese manufacturer [[OLFA]] in 1956 as the world's first snap-off blade and was inspired from analyzing the sharp cutting edge produced when glass is broken and how pieces of a chocolate bar break into segments. The sharp cutting edge on these knives is not on the edge where the blade is snapped off; rather one long edge of the whole blade is sharpened, and there are scored diagonal breakoff lines at intervals down the blade. Thus each snapped-off piece is roughly a parallelogram, with each long edge being a breaking edge, and one or both of the short ends being a sharpened edge.

==== Box cutter knife ====
{{Redirect2|Box cutter|Boxcutter}}
Another utility knife often used for cutting open [[Cardboard box|boxes]] consists of a simple sleeve around a rectangular handle into which single-edge utility blades can be inserted.  The sleeve slides up and down on the handle, holding the blade in place during use and covering the blade when not in use.  The blade holder may either retract or fold into the handle, much like a folding-blade pocketknife.  The blade holder is designed to expose just enough edge to cut through one layer of [[corrugated fibreboard]], to minimize chances of damaging contents of cardboard boxes.

<gallery widths="200px" heights="200px">
File:Safety cutter and simple box cutter blades extended.jpg|A modern safety cutter at top, with blunted tip blade and cutting guide/tape hook. At bottom, an older style simple plastic box cutter using standard straight edged blades.
File:Cutter olfa.jpg|[[OLFA]] segmented blade or "snap-off blade" utility knife
File:BoxCutter.jpg|Inexpensive stamped steel and aluminum box cutter with disposable blade
</gallery>