Full Text Searchable PDF User Manual
AR-15 Easy Jig® MANUAL
Warnings and safety notice
READ ALL INSTRUCTIONS AND WARNINGS BEFORE USING THE PRODUCT.
DO NOT USE THIS PRODUCT IF YOU DO NOT UNDERSTAND THE
INSTRUCTIONS AND WARNINGS. FAILURE TO READ THESE INSTRUCTIONS
AND TO FOLLOW THESE WARNINGS MAY RESULT IN SERIOUS INJURY OR
DEATH TO YOU AND OTHERS AND DAMAGE TO PROPERTY.
This manual should always accompany your jig and be transferred with it upon
change of ownership. A copy of the manual can be downloaded for free from http://
www.80PercentArms.com/pages/manuals or by contacting 80 Percent Arms.
Using this product on an 80% lower will convert the 80% lower into a firearm. Even
if the 80% lower is not fully milled or completed, it may still be legally considered a
firearm. It is your responsibility to comply with all federal, state and local laws and
regulations regarding the ownership, possession, and transportation of a firearm.
Certain configurations of the lower created by the end-user with an upper, may
subject the firearm to classification under the National Firearms Act, which imposes
registration, taxes, and other requirements on the owners of such firearms.
Working with power tools and cutting metal is inherently dangerous. Follow all
safety instructions provided by the power tool’s manufacturer. By using this product
you agree that you are aware of these risks, and agree not to hold 80 Percent Arms
liable for any injuries or property damage that may occur through the use of our
product. Proceed at your own risk.
80 Percent Arms warns all users of our products to exercise extreme caution in the
handling of any firearm. Because any firearm is potentially dangerous, the user
should successfully complete a recognized firearms safety course before handling
or employing any firearm. Before attaching your finished lower receiver to an upper
receiver, ensure that the safety and trigger mechanisms are functioning properly.
This must be done BEFORE the lower receiver is attached an upper receiver or
made capable of firing. If you are not an experienced gunsmith, we recommend
taking your completed lower receiver to a licensed gunsmith who can ensure that
it is functioning properly, and that the safety is in good working order. Remember
that you are the most important safety device when it comes to the safe handling of
your firearms. By using our product you further agree that 80 Percent Arms will not
be held liable for any personal injury, death or property damage that results from
the use of any firearm created with our products. If you do not agree to these terms,
please do not use this product, and contact us to return your unused product for a
Under no circumstances shall 80 Percent Arms be responsible for incidental or
consequential damages with respect to economic loss, injury, death or property
damage, whether as a result of breach of warranty, negligence or other-wise.
Some States do not allow the exclusion or limitation of incidental or consequential
damages, so the above limitation or exclusion may not apply to you.
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MESSAGE FROM 80 Percent ARMS
Thank you for purchasing our 80 Percent Arms Easy Jig®. Our patented
router based milling system is the fastest, easiest, and most popular method
to mill your 80% lower at home using common household tools. Our jig’s
heavy duty construction ensures your jig will last a very long time and allow
you to complete many lowers before needing any replacement parts.
For best results, we strongly recommend that you read this manual
from start to finish before getting started with your build. It’s very
important that you are familiar with all the steps you will need to perform to
minimize the chance of making a mistake. If you have any questions after
reading the manual, please contact us for assistance. We highly recommend
watching our video tutorial prior to milling your lower. Additional resources
including video tutorials and online manuals are available at our web site at:
important safety notice
Eye and hearing protection must be worn at all times when operating
any of the power tools required to finish your 80% lower. You must wear
impact resistant safety goggles at all times to protect your eyes from flying
debris and chips while drilling and milling. Do not wear open style safety
glasses as they do not provide protection from flying chips. Never use
compressed air to blow or clear metal chips. Instead, use a Shop-Vac to
suck out chips from your jig and work area.
Most good quality small laminate routers with a 1/4” collet can be used with
the Easy Jig®. They may be fixed or variable speed. Full size routers may
also be used along with a spacer to provide clearance for the buffer tube when
milling the trigger slot; however, we recommend using a smaller laminate
router for best results. Recommended routers include the Home Depot Ridgid
#R24012, Porter-Cable PCE6430, and Dewalt DWP611. Economy routers
such as Harbor Freight and Black & Decker brands should be avoided.
For best results, set you router speed to 24,000 - 30,000 RPM. Cutting fluid
is recommended to prolong the end mill and drill bit life, and to achieve a
smoother finish. Keep the flutes and shank of the end mill lubricated at all
times. Clear out chips after each pass for longer tool life and a smoother
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included parts illustration
PURCHASEd SEPARATELY easy Jig® tool kit
Right Jig Wall (1pc)
Left Jig Wall (1pc)
Pocket Drilling Block (1pc)
Template Spacer (1pc)
Trigger Pocket Template (1pc)
Rear-Shelf Pocket Template (1pc)
Router Base Support Plate (1pc)
Included Bolt Set
#08: Jig Wall Bolts 2.5” (4 pcs)
#09: Template Bolts 1.75” (4 pcs)
#10: Trigger Milling Bolts 0.75” (2
• Router (w/ 1/4” collett)
• Drill (Hand or Drill Press)
• Table Vise or 2 Table Clamps
• 1/8” Allen Wrench (for template
• 3/16” Allen Wrench (for jig bolts)
• 3/32” Allen Wrench (for stop collar
on drill bit)
• Cutting fluid such as Tap Magic,
Relton A9, Oatey Dark Cutting Oil
mineral oil, or motor oil.
• Masking tape
• Eye and hearing protection
end mill caution notice
The drill bits and other tools required to use the Easy Jig® are available at
most local hardware stores, or you may already have them at home; how-
ever, the required 1/4” end mill is custom made for 80 Percent Arms with very
short flutes to work with the Easy Jig®. Using any other type of end mill
may cause permanent damage to your jig which is not covered by the
You can purchase just the 1/4” end mill, or a complete tool kit with all the
drill bits and the end mill, from 80 Percent Arms or from the store where you
purchased your Easy Jig®.
Easy Jig® Tool Kit Includes:
1/4” x 4” long 3-flute Solid Carbide
End Mill with 0.75” flute cut length
3/8” drill stop collar
3/8” drill bit
5/32” Jobber Length Drill Bit
19/64” Jobber Length Drill Bit
Drill Bit advice
Use sharp high quality drill bits designed
for drilling aluminum, such as those sold
with our Easy Jig® Tool Kit. Using dull or
low quality drill bits will make drilling very
slow and difficult. This is very important
when drilling through the harder 7075
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Attach side plates #01 and #02 to lower receiver using the Jig Wall Bolts
#08. Tighten the (4) bolts in an alternating manner. Do not over tighten
bolts, just snug with an Allen key. Use masking tape or painter’s tape to
mask all areas of the receiver that will not be machined. Do not place
tape between mating surfaces.
Attach the pocket Drill Block #03 to the top of the jig using the #09
Bolts. Alternate tightening the top bolts to ensure you have your jig walls
parallel and spaced apart correctly. Use a piece of tape to cover up the
two rear pocket holes located on the “REAR” side of the pocket drilling
The last two holes reside above the rear pocket which sits higher
than the rest of the pocket—do not drill out these holes yet.
Prepare the 3/8” Drill #13 and 3/8” Drill Stop #12 to the appropriate length
by using the Rear Shelf Pocket Template #06 labeled MAIN. Securely
tighten the drill stop collar. The drill bit should be touching the bottom of the
depth gauge. Before drilling out the 8 holes, secure the jig assembly in your vise.
Drill out the 8 holes checking the drill bit length using the template
depth gauge after each hole. If you’re using a hand drill, make sure you
drill straight down—do not lean at any angle.
Slow down and reduce the
pressure when your Drill Collar gets close to touching the Drill Block. Avoid
allowing the stop collar to touch the drill block in order to prevent the drill stop
collar from sliding and over-drilling the hole. We suggest using cutting fluid
while drilling and a shop-vac to periodically clear out the chips as you drill.
Drill the two rear holes for the rear shelf. (
If your lower already
has the rear shelf lug area milled out, skip step 5 completely and go
to step 6.) Remove the top rear jig bolt so you do not drill through it.
Remove the tape to expose the REAR drill block holes. Prepare the 3/8” Drill
#13 and 3/8” Drill Stop #12 to the appropriate length by using the Trigger
Pocket Template #05 labeled REAR. Removing the rear Jig bolt can cause
the lower to slip downward if the vise is not tight enough. Re-insert the bolt
into the left jig wall and thread in only 7/8” of the tip of the bolt into the left jig
wall. The tip of the bolt will go partially into the the edge of the lower to keep
the lower from slipping, but not so far as to get in the way of the bit. Drill
out the 2 remaining rear shelf holes. When you’re done, remove the Pocket
Drilling Block #03 and use a shop-vac to clean the jig and lower of chips.
Prepare to mill the trigger pocket by placing the Template Spacer #04
with the notched end towards the receiver extension hole (buffer tube hole).
Then stack the Trigger Pocket Template #05 so that the smaller end and
the hole on the template is toward the buffer tube hole, and the raised lip
on the template is facing up.
Place the Router Base Support Plate #07 over the lip of the template
with the recessed bolt holes facing up. The router base only fits flush
one way, so if your holes don’t line up, rotate the support plate 180 degrees.
Attach the plate using the #09 Template Bolts, tightening the bolts to the
top of the jig walls in the same alternating fashion. Secure the assembled jig
in the vise with the buffer tube hole closest to you.
Install the 1/4” End Mill #11 into your router making sure the end mill
is very tightly secured in the collet to prevent it from creeping out while
milling. Adjust the cutting depth by using the depth gauge on the Rear
Shelf Pocket Template #06 labeled MAIN. Adjust the depth of the router
so the tip of the end mill is just below the first hash mark on the template.
Re-insert and tighten the top rear Jig Bolt #08 through the lower if it was
previously removed or loosened during step #5.
With the router off, insert the end-mill into the center of the furthest hole
from you. The tip of the end-mill should be just below the top of the 3/8” hole
you drilled out earlier. Maintain a firm grip on the router when turning it on.
For your first cutting pass, only focus on removing material between
the holes using a zig-zag pattern until all the holes are connected. Do not
change the depth of the end-mill yet.
Always turn off the router and wait for it to completely stop
rotating before removing or inserting it into the jig or lower. Failure to
do so may damage your lower and jig.
Once all of the holes are connected you can begin milling out the rest of
the area. Start from the middle and work outwards in a clockwise direction.
Keep doing this until the end mill shank is riding against the template. Once
the first pass is complete, move the router to the middle of the pocket and
turn it off before lifting it out of the jig. Wait until the end mill stops moving
before lifting it out of the jig. Clear chips frequently with your Shop-Vac to
avoid re-cutting chips. Keep the end mill lubricated when milling.
Continue taking deeper cuts by adjusting the end mill using the depth
gauge on the Rear Shelf Pocket Template #06 labeled MAIN. For 6061
lowers increase the depth of the end mill incrementally 1/4 to 1/3 notch for
each pass until you bottom out the end mill inside the depth gauge. For 7075
lowers increase the depth by only 1/6 to 1/4 notch. Each time, start inside
one of the 3/8” holes and work from the middle out in a clockwise direction.
(Each image in A-D shows a 1/4 notch or hash mark incremental move.
For the final pass, set depth to very top edge of gauge as shown in E.)
On the last two passes before getting to the bottom, the end
mill will not have a pre-drilled hole to start in. To prevent the end mill from
jerking when powering up the router, hover the router slightly above
the template and power up the router without the end mill touching the
lower. Then, very slowly, lower the router while maintaining a firm grip
on the router. For the final pass, the end mill depth is set so the end mill
is past the last notch and touching the top of the depth gauge.
When this process is complete, you’ll have the main trigger pocket milled out
and two rear shelf holes drilled out.
Keep the jig and the lower clear of chips during the milling process for
best results. Go slowly and adjust the depth back a 1/4 notch if necessary
if you hear excessive noise or feel
If your lower came with the
rear shelf area milled out, you do
not need the two rear holes drilled
as shown. The front trigger pocket
does not need to be connected to
the rear shelf / lug pocket.
Prepare the jig to mill the rear shelf.
If your lower already came with the rear shelf / lug area milled out,
skip step 12 and 13 and move directly to step 14.
Remove the Router Base Support Plate #7 and the Trigger Pocket Template
#5. Set the Rear Shelf Template #6 on top of the Template Spacer #4 so
that the longer hole is closer to the buffer tube hole, and the raised lip of the
template is facing up. Next, place the Router Base Support Plate #7 over
the lip of the template with the recessed bolt holes facing up. Attach the
plate using the Template Bolts #9. Tighten the bolts to the jig walls in an
alternating pattern. Secure the assembled jig in the vise with the buffer tube
hole facing away from you.
Next, pull out the top rear Jig Bolt #08 so you do not mill through it.
Removing the jig bolt completely can cause the lower to slip downward if the
vise is not tight enough. Re-insert and thread the tip of the bolt 7/8” through
the top left jig wall threaded hole. The tip will go into the edge of the lower
and keep the lower from slipping without getting in the way of the end mill.
Adjust the end-mill to the appropriate length to mill the rear shelf by
using the depth gauge on the Trigger Pocket Template #05 labeled
Adjust your router depth so the end mill is touching the first notch / hash mark
on the template depth gauge. Use the same milling process of connecting
the holes and milling as outlined in Steps 9, 10 and 11.
: Do not mill out the smaller hole (trigger slot) of the Rear Shelf
Template #6 during this step. If you removed or loosened the top rear
Jig Bolt in step 12, be sure to reinsert and tighten the jig bolt before
moving to the next step.
To complete the trigger slot remove all the top plates and the template
spacer. Clear away chips from the lower and side plates. Reinsert and tighten
the Rear Jig Bolt #08. Place the Trigger Pocket Template #05 on the jig
with the depth gauge facing down. Attach the Trigger Pocket Template #5
to the jig side plates, inserting only the 2 short Trigger Milling Bolts #10 into
the two holes on the template closest to the buffer tub. Use the two jig wall
screw holes furthest away from the buffer tube to secure the template.
Secure the Jig into the vise. Using the 19/64” drill #15, slowly drill the pilot
Use very little downward force when drilling the pilot hole.
It is possible to drill past the bottom of the trigger area and into the trigger
guard below if pressing too hard. Make sure to go slowly and control the
downward pressure at all times.
If you are using a hand drill, it’s important that you drill the pilot hole
very straight. Do not drill at an angle or the pilot hole may drift outside the
boundary of the trigger slot template. Use a punch, if available, to further
prevent the drill bit from walking when you start drilling. Use very little
downward force and go slowly when drilling the pilot hole to prevent
the drill bit from walking.
To mill the trigger slot, remove the Trigger Pocket Template #05 and
set the Rear Shelf Pocket Template #06 on the jig, with the raised
lip facing up. Secure the Router Base Support Plate #07 on top of the
template using only the 2 short Trigger Milling Bolts #10. Only use 2 bolts
to attach the template and base plate. Insert the screws into the 2 holes on
the base plate closest to the buffer tube, using the 2 screw holes on the jig
side plates furthest from the buffer tube. The smaller trigger slot should be
located closest to the buffer tube. The larger slot over the magazine well
is not used. Adjust the router depth setting so the end mill is slightly
inside the drilled out trigger slot pilot hole. With the end mill centered in
the hole, turn on the router while keeping a firm grip on the router. Mill back
and forth in a clockwise motion. Turn off the router and increase the depth
by 1/6 to 1/4 notch and repeat the process. Continue until the trigger slot is
fully milled out.
Only if using a full sized router with a large base, insert the Template Spacer
#04 between the Pocket Template #06 and the jig wall, and use 2 of the longer
1.75” Template Bolts #9 instead of the short Trigger Milling Bolts. This will elevate
the Router Support plate to allow a larger router base to clear
the buffer tube
Remove all of the template top plates to drill the trigger, hammer and
safety selector holes. Clear out chips and reposition the jig and lower on its
side. Because the bolts holding the jig together may stick out of the jig side
plates, use spacers (such as the template plates) to raise the jig assembly so
that it is laying level. Secure the jig on its side with a vice or clamp.
: If using a hand drill, make sure you drill straight down. Do not lean
at any angle.
Insert the 5/32” Drill #14 into your drill press or hand drill and drill out the
trigger and hammer pin holes on the right side. Next, install the 3/8” Drill #13
and drill out the safety selector hole on the right side. Flip the jig over and do
the same for the left side. Do not drill all the way through from one plate
to the other. Measuring from the top surface of the jig side plate, do not drill
deeper than 1.25” to prevent drilling into the opposite wall of the lower.
: To ensure proper function, use a paperclip to clear out any chips
from the safety selector detent hole. It’s common to have chips stuck in
the selector detent hole which will interfere with the function of the safety
selector. These chips are not always easy to see. It’s a good idea to push a
paper clip though the safety selector detent hole even if you don’t see any
chips in there to clear out any hidden chips.
clean up tips
During milling, it’s possible for small chips to rub between the jig plates and
the lower. Aluminum residue from the chips can rub onto the anodized finish
of the lower. The anodized finish on the lower is much harder than the raw
aluminum chips. You can use a sponge with a mildly abrasive green Scotch
Pad to remove marks left on the lower by the chips. Dip the sponge in soapy
water and gently rub the lower to remove any marks.
If you milled a raw lower, do not apply a finish coat to the lower until after
you have installed your lower parts kit and performed a function test.
If you milled an anodized or Cerakoted lower, it is not necessary to apply a
finish to the milled raw aluminum area.
Show off your work
There’s a great sense of satisfaction in building your own firearm. Join
our community of builders on Facebook where you can display your work,
see what others have done, and keep up with 80% news and new product
announcements. Join us at www.facebook.com/80percentarms.
Our dedicated support team is available by phone, email, and walk-in to
answer your questions and for any service needs.
80 Percent Arms Inc.
3480 W Warner Ave., Suite N
Santa Ana, CA 92704
Phone sales and support: (949)-354-2767
Email support: email@example.com
“Easy Jig” is a registered trademark or trademark of 80 Percent Arms Inc. The
product covered by this manual is protected under copyright, patent, and other
intellectual property rights. The router based Easy Jig® milling system is patented
and is the exclusive intellectual property of 80 Percent Arms Inc. Unauthorized use
of our router milling system, in whole or in part, is prohibited. Patent violations are
strictly enforced. All images and content in this manual are copyright © 80 Percent
Arms Inc. Unauthorized duplication or distribution of the contents of this manual
without the prior written permission of 80 Percent Arms is prohibited. No part of
this manual may be reproduced, stored in a retrieval system, or transmitted, in any
form, or by any means, electronically, mechanically, by photocopying, or otherwise,
without the prior written permission of 80 Percent Arms Inc.
PARTS AND ACCESSORIES
80 Percent Arms carries a complete line of replacement parts for the
Easy Jig® and other parts and accessories to finish your build project,
including matching 80 Percent Arms billet upper receivers. Visit us
at www.80PercentArms.com to browse our full catalog of parts and
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security of a free State, the right of the people to
keep and bear Arms, shall not be infringed.”
Copyright © 2016, 80 Percent Arms Inc.