Brownells YAVAPAI 1911 AUTO Instructions

The Brownells/Yavapai 1911 Auto Sear Tool gives the pistolsmith an easy
to use, dual purpose jig for making sear alterations to most variations of
the 1911 Auto Pistol. With this jig you can consistently and accurately cut
both the primary and secondary sear angles, plus the unique, compact, tube
microscope allows you to visually inspect your alterations to the sear and
hammer and their relationship to one another.
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WARNING
Never attempt to disassemble or reassemble a firearm unless you are
absolutely certain that it is empty and unloaded. Visually inspect the
chamber, the magazine and firing mechanism to be absolutely certain
that no ammunition remains in the firearm. Disassembly and reas-
sembly should follow the manufacturer's instructions. If such instruc-
tions are not immediately available, contact the manufacturer to see
if they are available. If they are not available at all, then you should
consult other reference sources such as reference books or persons with
sufficient knowledge. If such alternative sources are not available and
you have a need to disassemble or reassemble the firearm, you should
proceed basing your procedures on common sense and experience with
similarly constructed firearms.
With regard to the use of these tools, the advice of Brownells Incor-
porated is general. If there is any question as to a specific application
it would be best to seek out specific advice from other sources and not
solely rely on the general advice and warnings given.
HOW TO USE
To ensure that the relationship between the sear and the hammer is cor-
rect, the hammer must first be prepped. Cut the hammer full cock notch to
a height of .018" (Figure A). Do this by first securing the hammer in a pad-
ded bench vise with the hooks facing up. Place an .018" thick metal shim on
top of the hammer hooks. Bring the hooks to height with a #4 cut file. Next,
stone the face of the full cock notch hooks to a bright mirror finish. Polish
the face of the hooks with a sharp edged stone like the Brownell's 6" x 6" x
1" Ceramic stones. These stones are shaped and then ground with sharp,
square edges so the critical 90° angle is maintained on the notch. After the
hammer hooks are cut to correct height and highly polished, you are ready
to move on to the sear (Figure B).
Install the finished hammer and the uncut sear onto the correct pins
(Figure C) provided with the jig so the contact surfaces of the hammer
and sear are visible through the hole below the parts. Place the fixture on
a light colored surface in a well lighted area with the microscope pointing
up. Loosen the rubber tipped screw that secures the microscope to the tool
body so that it can move up and down. Move the scope up or down until the
hammer and sear are in focus. (The end of the scope about an inch above the
parts will usually bring them into focus). Observe the relationship between
the hammer full cock notch and the sear.
Remove the sear from the fixture and apply a coating of Dykem
permanent marker to the sear's primary hammer contact surface. Install the
sear back onto the jig. Rotate the parts until they connect as they would if
they were in the pistol. Work the sear and hammer together as if they were
actually functioning.
Remove the sear and observe the wear marks on the sear's primary con-
tact surface. Observe where the hammer was rubbing against contact sur-
face. This is done to determine how the sear will be positioned on the jig to
be stoned. Place the sear in the sear slot opposite the roller and secure it
by placing your sear pin through the jig and the sear (Figure D). Be sure
the bottom screw is turned all the way into the jig. Adjust the top screw
outward so that when the sear is pushed against the adjusting screw, and
a six inch stone is laid upon the roller and the sear, the stone will cut on
the same surface that the wear marks indicated with the earlier test. Once
this position has been determined, turn the bottom screw outward until it
contacts the sear legs. This positions the sear securely in the jig so the sear
cannot move during stoning.
Reapply some Dykem or marker to the contact surface of the sear. As
you begin to stone the sear, the Dykem provides a visual check to ensure
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the stone is cutting the sear where you intend it to. Determine which type
of stone to use on the sear first by how rough the sear's contact surface is.
If there are rough machine marks, start off with a medium india stone and
progress to a medium-fine ceramic and then on to an extra-fine ceramic
stone. Move the stone across the top surface of the roller and the sear face
with light, even, downward pressure. Light pressure is sufficient. Excessive
downward pressure will remove too much material from the sear and cause
the roller to wear. If the manufacturer's instructions call for lubrication or
wetting on the stone, be sure to follow those directions. Stone the contact
area until it becomes a highly-reflective, mirror surface. Apply another
coat of Dykem or marker to the polished surface and assemble the sear and
contact between the parts. Observe the relationship between the hammer
and the sear's contact through the microscope. When they are properly fit,
the hammer and the sear's contact surface should perfectly flat against
or black
™
each other (Figure E). Full, equal contact must be made on the sear by
both hammer hooks.
The secondary surface must now be cut on the sear. Install the adjustment
screw with the thin head into the top screw position and turn it all the way
into the jig. Place the sear into the jig as shown in (Figure F). Push the sear's
legs up to secure the sear into position with your finger. Position a fine india
stone onto the jig. Repeat the stoning directions given above. Cut the second-
ary angle until it is about 1/3 the width of the primary surface (Figure G).
Reassemble pistol and check safeties for proper functioning.
Reassemble the firearm according to the manufacturer's instructions.
Check for proper functioning using ACTION PROVING DUMMIES. Make
sure ALL SAFETY MECHANISMS are fully functional as designed and
approved by the manufacturer. If these tests prove satisfactory, test-fire
the firearm with live ammunition in a SAFE and APPROPRIATE manner.
IMPORTANT! Start the live ammunition tests by first loading an ACTION
PROVING DUMMY, then a live round, into the magazine. Only after sev-
eral tests have been conducted in this manner should additional rounds be
placed in the magazine and fired.
©
2015 BROWNELLS, INC.
/YAVAPAI
1911 AUTO
SEAR TOOL
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