Editing Screwdriver (section)

== Variations ==
=== Torque screwdrivers ===
{{Main|Torque screwdriver}}
Screwdrivers are available—manual, electric, and pneumatic—with a [[clutch]] that slips at a preset torque. This helps the user tighten screws to a specified torque without damage or over-tightening. Cordless drills designed to use as screwdrivers often have such a clutch.

=== Powered screwdrivers ===
[[File:Шуруповёрт в работе.ogv|thumb|How to use a cordless drill as a powered screwdriver]]
Interchangeable bits allow the use of powered screwdrivers, commonly using an electric or air motor to rotate the bit. [[Cordless drill]]s with speed and torque control are commonly used as power screwdrivers.
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<gallery mode=packed>
File:ElectricScrewdriver.JPG|A rechargeable battery-powered electric screwdriver
File:Werkzeugbit extra lang IMGP9240.jpg|Compact electric screwdriver with extended bit
File:US Navy 061125-N-6889J-033 Builder 3rd Class Mathew Speece of Naval Mobile Construction Battalion Seven Four (NMCB-74) secures the frame of a wall at Camp Ramadi.jpg|Cordless drill being used to drive screw fastener
</gallery>

=== Ratcheting screwdrivers ===
[[File:Spiral-screwdriver.jpg|thumb|right|Stanley Yankee No 130A, spiral or ratchet screwdriver]]
Some manual screwdrivers have a [[Ratchet (device)|ratchet]] action whereby the screwdriver blade locks to the handle for clockwise rotation, but uncouples for counterclockwise rotation when set for tightening screws—and vice versa for loosening.

Spiral ratchet screw drivers, often colloquially called ''[[Yankee screwdriver]]s'' (a brand name), provide a special mechanism that transforms [[linear motion]] into [[rotational motion]]. Originally the "[[Yankee screwdriver|Yankee]]" name was used on all tools sold by the [[North Brothers Manufacturing Company]] but later, after [[Stanley Black & Decker|Stanley]] purchased the company, it became synonymous with only this type of screwdriver. The user pushes the handle toward the workpiece, causing a [[Ratchet (device)|pawl]] in a [[spiral]] groove to rotate the shank and the removable bit. The [[ratchet (device)|ratchet]] can be set to rotate left or right with each push, or can be locked so that the tool can be used like a conventional screwdriver. One disadvantage of this design is that if the bit slips out of the screw, the resultant sudden extension of the spring may cause the bit to scratch or otherwise damage the workpiece.

Once very popular, versions of these spiral ratchet drivers using proprietary bits have been largely discontinued by manufacturers such as Stanley. Some companies now offer a modernized version that uses standard {{frac|1|4}}-inch hex shank power tool bits. Since a wide variety of drill bits are available in this format, the tool can do double duty as a "push drill" or [[Persian drill]].