US 9,810,517 B2
Method for machining a firearm lower receiver using a jig
Charles E. Chang, Coto de Caza, CA (US); Wayne R. Partington, Santa Ana, CA (US); Tilden A. Smith, II, Santa Ana, CA (US); and Jules Johannes de Neve, Huntington Beach, CA (US)
Assigned to 80 Percent Arms Inc., Santa Ana, CA (US)
Filed by 80 Percent Arms Inc., Santa Ana, CA (US)
Filed on Mar. 19, 2015, as Appl. No. 14/662,384.
Application 14/662,384 is a continuation of application No. 14/534,413, filed on Nov. 6, 2014, granted, now 9,009,986.
Claims priority of provisional application 61/902,357, filed on Nov. 11, 2013.
Prior Publication US 2015/0192401 A1, Jul. 9, 2015
Int. Cl. B23P 13/00 (2006.01); G01B 5/14 (2006.01); F41A 3/66 (2006.01); G01B 5/18 (2006.01)
CPC G01B 5/14 (2013.01) [B23P 13/00 (2013.01); F41A 3/66 (2013.01); G01B 5/18 (2013.01); Y10T 29/49771 (2015.01); Y10T 29/49778 (2015.01)] 20 Claims
OG exemplary drawing
 
1. A method of machining a firearm, the method comprising the steps of:
providing an unfinished firearm lower receiver, the firearm lower receiver defining a top plane that is aligned with a top surface of the firearm lower receiver but below a buffer tube receiver extension of the firearm lower receiver;
providing a first side jig and a second side jig configured to be disposed on opposite sides of the firearm lower receiver and configured to removably attach to one another securing the firearm lower receiver therebetween;
attaching the first and second side jigs to the firearm lower receiver;
providing a drill block jig removably attachable to the first and second side jigs disposed above the top surface of the firearm lower receiver, wherein the drill block jig comprises a plurality of through holes defining axes oriented perpendicular to the top plane of the firearm lower receiver when the drill block jig is attached to the firearm lower receiver;
attaching the drill block jig to the first and second side jigs;
drilling with a drill bit into the firearm lower receiver using the plurality of through holes in the drill block jig as a guide;
removing the drill block jig;
providing a template spacer jig removably attachable to the first and second side jigs disposed above the top surface of the firearm lower receiver, wherein the template spacer jig comprises a spacer aperture disposed through a template spacer thickness, wherein the spacer aperture is oriented perpendicularly through the top plane of the firearm lower receiver when the template spacer jig is attached to the firearm lower receiver;
providing a first pocket template removably attachable and disposed onto the template spacer jig, wherein the first pocket template comprises a first aperture disposed through a first pocket template thickness, wherein the first aperture is oriented perpendicularly through the top plane of the firearm lower receiver when the first pocket template is attached to the template spacer jig;
providing a second pocket template removably attachable and disposed onto the template spacer jig, wherein the second pocket template comprises a second aperture disposed through a second pocket template thickness, wherein the second aperture is oriented perpendicularly through the top plane of the firearm lower receiver when the second pocket template is attached to the template spacer jig;
providing a router support plate disposed onto either the first or second pocket template and attachable to the first and second side jigs through the first or second pocket templates and the template spacer jig, wherein the router support plate comprises a router aperture disposed through a router support plate thickness, wherein the router aperture is oriented perpendicularly through the top plane of the firearm lower receiver when it is attached onto the first or second pocket templates, and wherein a top surface of the router support plate is disposed equal to or above the buffer tube receiver extension;
placing the template spacer jig onto the first and second side jigs;
placing the first pocket template onto the template spacer jig;
attaching the router support plate to the first and second side jigs securing therebetween the first pocket template and template spacer jig;
routing with a router into the firearm lower receiver as defined by the first aperture of the first pocket template;
substituting the second pocket template in place for the first pocket template; and
routing with the router into the firearm lower receiver as defined by the second aperture of the second pocket template.