Instructional videos and written instructions on this page cover:
- How to install the 5D Tactical Universal Router Adapter.
- How to assemble the 5D Tactical Router Jig.
- Tools and accessories needed for finishing an 80% lower with our Jig.
- The Router Jig Instructions for use.
- Helpful hints and tips.
Router Jig PRO: 80% Lower Jig Instructions
If you’re looking for the easiest, fastest, and most durable 80% router jig to finish your AR-15, AR-9 or AR.308 lower receivers, the
Router Jig PRO from 5D Tactical delivers the best, quality finished results for your next custom AR build. With our Router Jig PRO, which is considered the most advanced 80% lower jig on the market today, even beginners can expect to finish their lowers in as fast as 45 minutes or less time. But how can you effectively use our router jig to ensure a perfect finish?
Here, we’re going to discuss the basic 80% lower jig instructions that you should follow when it comes to ensuring easy and safe use of our Router Jig PRO during the drilling and milling process.
To start off, you need to understand how to assemble your jig correctly. First, clean the surface of the 80% lower receiver and apply masking tape to the sides before applying the buffer plate to the back of the receiver. The gray buffer plate provided is for AR-15/AR-9 receivers while the black buffer plates are for .308/AR-10 receivers. Follow the instructions provided to loosely thread the buffer adapter into the receiver until it’s pressed against the back of the receiver.
After completing that step, loosely install the takedown adapter to the guide plate using the provided jig screws while ensuring that you’re using the right colored adapters for your specific AR build. Align your lower receiver with the takedown adapter and pass the correct takedown pin through the receiver and adapter. Also make sure that the holes in the rear of the guide plate align with the buffer plate, and then loosely install the jig screws.
It’s now time to tighten the jig screws to secure the buffer plate and takedown adapter. Just make sure you’re grasping the guide plate while tightening the screws, after which you need to orient the side plates, observing left and right with the flat sides facing out. After this, set the guide plate and lower receiver assembly atop the side plates and loosely thread the jig screws and then tighten. Make sure to clamp your jig assembly securely in a vise by the notches provided in the side plates. Review the 80% lower jig instructions carefully to avoid any damage.
Initial Drilling Process
Once you have completed setting up your jig assembly, the next step is drilling your lower receiver. To ensure smoother drilling, spray WD-40 into the drill guide hole and insert a 21/64” drill bit. As outlined in the 80% lower jig instructions, don’t start the drill until you’re sure the bit is fully inserted. Begin drilling while making sure that the drill bit is kept straight and perpendicular to the receiver. Make sure to periodically pull the drill out of the guide hole to clear any chips. Apply WD-40 when necessary. Drill until the drill bit exits the bottom of the lower receiver and then uninstall the drill guide by removing the two jig screws.
When it comes to the milling process, it’s important to note that the provided depth gauge hash marks denote the maximum depth of cut per pass. If you’re a beginner or a custom AR builder seeking maximum finish quality, you should make milling passes at less than a full hash mark. Attempting to mill at depth increments higher than what is recommended can cause damage to the end mill or receiver. Ensure that your router base lock is tight and functioning properly. If the router depth moves while milling, the end mill or the receiver can be damaged.
If you’re using a variable speed router, set to the highest speed setting. Don’t insert or remove the end mill while the router is spinning. Prior to turning the router on, ensure that the end mill is centered within the milling pilot hole and not contacting any part of the receiver. While milling, you’ll want to move the router smoothly and in a clockwise manner as shown in the 80% lower jig instructions. Keep the router adapter flat against the router guide plate at all times. You’ll also want to avoid exerting excessive pressure or abruptly pulling the router.
Slowly nibble away at the lower receiver, and in case you start experiencing chattering, you’ll want to slow down and take shallower depths of cut. Remember to apply WD-40 sparingly and remove chips frequently. There are three main milling steps in the instructions which start with installing the short guide pins to the router adapter using the provided guide pin screws and 7/64” Allen wrench, eventually working your way up to the medium and long guide pins to finish your milling process. In each step, you’ll want to mill gently in a clockwise manner while following the recommended steps as shown in the 80% lower jig instructions.
For the final drilling process, clamp your jig assembly in the vise by the edges of the side plates, with the right side facing up. Ensure that the jig assembly is level and spray WD-40 into the large guide hole and insert 3 /8” drill bit. Only start the drill when you’re sure that the bit is fully inserted into the guide hole. When you start drilling, apply moderate pressure until the drill penetrates the right side wall and continue drilling through the left side. After this, spray WD-40 into both of the small guide holes and insert 5/32” drill bit into either of the remaining guide holes.
Apply moderate pressure when drilling and drill until the bit penetrates the right side of the wall and continue doing so through the left side wall. Repeat the same process for the remaining small hole. In case your drill bits are not long enough to penetrate through both walls, flip the jig over and repeat the process. Receivers with spray-on coatings like Duracoat and Cerakote should be drilled from both sides for maximum finish quality.
Removing Your Finished Lower Receiver
Once you’ve completed your final drilling, it’s time to remove your lower receiver from the jig assembly. Start by removing the buffer adapter, loosen or completely remove the buffer plate, remove the takedown pin and then remove your finished receiver from the Router Jig PRO. Make sure to follow the steps provided with your 80% lower jig instructions so you can do it correctly.
Get the Best Custom AR Router Jig from 5D Tactical
At 5D Tactical, we provide our clients with a range of AR-15 and AR-308 build parts like the universal 80% lower
Router Jig PRO to ensure easy and fast finishing of your lower receivers. If you need help finishing your lower, contact us today or call at 508-834-4223.
Shop 5D Tactical for the best parts to complete your custom AR build!