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80% Arms AR-15 Easy Jig Manual

Made by: 80% Arms
Type: Manual
Category: Power Tool
Pages: 20
Size: 7.78 MB


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AR-15 Easy Jig® MANUAL



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Warnings and safety notice






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.

- 1 -


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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. 

Router information

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 


- 2 -


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included parts illustration











PURCHASEd SEPARATELY easy Jig® tool kit








 3 -


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included parts


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


required tools

•  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  

aluminum lowers. 

- 4 -


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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 

template #03. 


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.


 5 -


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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.


 6 -


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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.



 7 -


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STEp 7

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.


 8 -


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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.


 9 -


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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 

excessive chatter.


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. 


 10 -







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STEP 12:

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. 


 11 -



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STEP 13:

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.



 12 -


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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 #08Place 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.


 13 -


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STEP 15:

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


 14 -



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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.


 15 -


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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.

Contact Us

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: support@80percentarms.com

Legal Notice


“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. 


 16 -


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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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“A well regulated Militia, being necessary to the 

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.