US 12,434,308 B2
Step drill bit
Douglas W. Allen, Oconomowoc, WI (US); Courtney D. McCool, Menomonee Falls, WI (US); Smith C. Theiler, Plymouth, WI (US); and Richard Hohnl, Jr., Racine, WI (US)
Assigned to MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed by MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed on Mar. 27, 2020, as Appl. No. 16/831,995.
Application 16/831,995 is a division of application No. 16/250,175, filed on Jan. 17, 2019, granted, now 10,695,845.
Application 15/668,874 is a division of application No. 14/297,777, filed on Jun. 6, 2014, granted, now 9,731,358, issued on Aug. 15, 2017.
Application 16/250,175 is a continuation of application No. 15/668,874, filed on Aug. 4, 2017, granted, now 10,252,351, issued on Apr. 9, 2019.
Claims priority of provisional application 61/831,926, filed on Jun. 6, 2013.
Prior Publication US 2020/0222994 A1, Jul. 16, 2020
Int. Cl. B23B 51/02 (2006.01); B23B 51/00 (2006.01)
CPC B23B 51/0081 (2013.01) [B23B 51/009 (2013.01); B23B 51/02 (2013.01); B23B 51/00 (2013.01); B23B 2251/40 (2013.01); B23B 2251/50 (2013.01); B23B 2251/52 (2013.01); B23B 2270/36 (2013.01); Y10T 408/21 (2015.01); Y10T 408/906 (2015.01)] 20 Claims
OG exemplary drawing
 
1. A drill bit comprising:
a shank extending along a bit axis;
a transition portion coupled to the shank; and
a body portion having a distal end and defining a plurality of axially stacked, progressively sized steps including a first step at the distal end and a terminal step coupled to the transition portion, each step including an axial relief formed on an upper edge of the step, the body portion further defining a body flute extending from the first step to the transition portion;
wherein a difference in hole diameters formed by each pair of adjacent steps of the plurality of steps is less than 0.1 inches; and
wherein the axial relief of each step is between approximately 0.007 inches and approximately 0.021 inches.