Drill bit shank

Shank Types for General Drilling
– Brace Shank
– Common before 1850 and still in production
– Tapered shank rammed into a square hole in the drill
– Various chuck designs invented for effective grip and drive
– Included angle of the taper is 8 ± 0.25 degrees
– Forge-made with wide tolerances and moderate torque transmission
– Straight Shank
– Most common style on modern drill bits
– Whole bit, shaft, and shank have the same diameter
– Held in a three-jaw drill chuck
– Reduced-shank or blacksmiths drill for larger diameter bits
– Silver & Deming (S&D) bits with reduced shanks for larger drills

Specialized Shank Types
– Hex Shank
– Flats machined on a round or hex bar stock
– Grasped by a 3-jaw drill chuck or chuck for hex shanks
– Common for machine screwdriver bits and compatible with screwdriver machinery
– High torque transmission with no slipping
– Cannot be held in a regular round collet, requires a special HEX collet
– SDS Shank
– SDS Plus shank diameter is 10mm, SDS Max is 18mm, and SDS Quick is 6mm
– Used for hammer drilling with masonry drills in stone and concrete
– Sliding action in the chuck prevents slipping during rotation
– Different sizes available: SDS Quick, SDS-plus, SDS-Top, and SDS-max
– Hilti TE-S system designed for chipping in larger applications
– Triangle Shank
– Made by machining three flats on round bar stock
– Held in a 3-jaw drill chuck, allowing higher torque transmission
– Limited slipping and can be held in a drill chuck
– Moderately accurate centering
– Cannot be held in a collet

Other Shank Types
– Square Shank
– Square taper drills used for large ratchet drills
– Used for drilling large holes or in thick plates
– Fits straight into a ratchet drill
– Ratchet drill used with strong arm for pressure
– Pushes the drill into the workpiece
– Threaded Shank
– Some drills, wire wheels, etc. use a threaded shank
– Cylindrical wire wheels used to clean inside pipes
– Large wood drills may have threaded shanks
– Small threaded drill bits and countersinks common in aircraft metal work
– Threaded countersink cutters used to create flush rivet holes

References
– SDS-plus tool insertion system
– Encyclopedia of technical terms (A-Z)
– Archived from the original on 2007-09-18. Retrieved 2010-04-11
– SDS
– Lexikon der Elektrowerkzeuge
– Archived from the original on 2007-08-16. Retrieved 2010-04-11
– Standard Dimensions of Sherline Tools
– Sherline.com
– Sherline Products Inc. Retrieved 30 April 2014
– Judge, Arther W (1947)
– Engineering Workshop Practice
– The Caxton Publishing Company Ltd. pp.Vol i 137

Related Topics
– Metalworking
– Machining and computing
– Computer-aided engineering
– 2.5D
– CAD
– CAM
– Drilling and Threading
– Die head
– Drill
– Drill bit
– Drill bit sizes
– Drilling
– List of drill and tap sizes Source:  https://en.wikipedia.org/wiki/Drill_bit_shank#SDS_shank