80% Lower Jig Tool Kits

Our Router Jig Extreme SpeedMill™ was designed by our engineers to help builders self-manufacture with the best and fastest milling results to get that mirror finish inside your 80% lower receiver’s trigger pocket. With a supported endmill, results are faster and cleaner than ever before as total runout has been reduced to near-zero, 

Modulus Arms is uniquely qualified in manufacturing tooling and offers complete Tool Kits that come with our patented endmill for your convenience as well. 


Take the guesswork out of the process with our specialized tools that are perfect for building your 80% lowers in your 80 lower jig regardless of its caliber (AR-9, AR-10, AR-15). Browse our accessories to deck out your build and flex on others with your upgraded AR15 parts and accessories. 

End Mills

When it comes to completing 80 lowers, end mills are critical as they’re what is used to remove the material in an 80 lower receiver to create the trigger pocket. The longevity of how long an end mill lasts can depend on the skill of the builder and whether it has our premium coating or not. We typically see standard end mills last 6-10 lowers while premium end mills will last up to 15 lower completions.

Drill Bits

Drills bits are also essential in completing 80 lowers. The three drill bits included in our tool kits are for creating the pilot hole in an 80 lower before you start milling, the hole for the safety select, and the holes for the trigger pins.  


There are many routers you can use to complete 80 lowers. That’s why we have 4 different sizes of end mills to be compatible with as many routers that are currently on the market. But if you’d like to take the guesswork out of it. We sell the 80 Percent Arms Freedom Jig Router (requires Size C or Version 3 end mill) which is small, portable, and optimized in its design for finishing 80% lowers. 

Large Router Plate

Should you choose to purchase or use a preexisting router that is rather large - you may require a large router plate adapter to properly fit for use in completing 80 lowers. Please refer to our product page description and check the compatibility list to see what brands’ routers require the large router plate.

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