fosscad/Misc/AR-15-Magazine_Spring_Bending_Jig-Ivanthetroll

AR-15 Magazine Spring Bending Jig - 'Grewal Jig'

Author

Ivanthetroll (@Ivanthetroll12)

Version

1.0

Description

This is a DIY AR-15 30 round mag spring bending tool. It does just want it sounds like; it helps you bend AR-15 Magazine springs for a 30 round AR-15 Magazine.

This jig is fairly simple to use, and should be possible to print on most printers. Its overall length is the only issue with printer compatibility.

I printed my jigs out of IC3D ABS, and recommend that, but anything that isn't junk will work. PETG and PLA will likely work. I used ABS because early versions of this jig needed to be split in half lengthwise and acetone welded together.

Here's a video link to using the jig - https://www.bitchute.com/channel/976M3ljonVw3/ - if it goes down for some reason, feel free to DM me on Twitter and I'll get you a vid. Also, any questions you may have - shoot em my way. Happy to help :) Feel free to share anything you find, or if you want to share springs you bend, please do.

How to use the jig:

1. Get the jig printed. There are three sections, make sure you print all three with flat side down (the middle section has two flat sides, either side down works). I used ABS, 100% infill helps, I had a few jigs break at 50%.
2. Get some .059 inch diameter spring wire. It is sold as music wire, piano wire, spring wire, etc. Here's the stuff I used: https://www.amazon.com/Carbon-Smooth-Diameter-Precision-Tolerance/dp/B0036R4SX4/ref=sr_1_4?ie=UTF8&qid=1544054714&sr=8-4&keywords=.059in+music+wire
3. Make sure you have some pliers. I used channel-locks in the video, but I think vise grips work well too.
4. Zip tie the jig parts together at 1/2 way down, and at the bottom of the jig. 5a. It really helps to have a vise. If you don't have one, think about getting one. You can use clamps and a couple 2x4s to approximate a vise, or if you're really trying to Khyber pass it, two 2x4s and bolts through them will work. 5b. You need to have four sections of angle metal longer than the jig (I used angle aluminum I had sitting around) and some spare mild wire (such as coat hangar wire).
5. Put the jig in the vise. Clamp down tight, but not tight enough to damage the jig.
6. This is where the video starts. Get your spring wire, feed it into the hole in the bending jig. It helps to have a 'key' or 90 degree bend in a 1/2 inch length of the wire that you pass through the jig to keep it locked in place.
7. Add the first coil. This is the hardest one, as the jig will try and move around. You can snug the vise down more to keep the jig still. You your hands to draw the wire around the jig, then pull tight, then crimp it with the pliers. You have to crimp pretty hard, don't be shy.
8. Continute adding coils down the jig. When you get to a zip tie, you can cut it and keep winding. Draw it around, pull it tight, crimp it. It is very important to pull it tight and keep it tight while you crimp. Once you need to move the jig or down (or flip it upside down in the vise is what I recommend), you just need to keep the most bend tight.
9. Once you reach the bottom of the jig, you are ready to terminate the wire. Get the last loop crimped, then cut it off with some extra length on the end. VERY IMPORTANT - remove the wire that you tucked through the hole in the beginning. It has to be removed BEFORE you wrap the spring in angle metal.
10. Take your angle metal and encapsulate the jig/spring like the video/pictures show. While holding the angle metal tight, wrap wire around the metal as show in the vid/pics. This will hold the assembly tight. Make sure there is no wiggle room for the angle metal, you want to hold the spring exactly as it is.
11. Put the assembly in the vise, and get a punch to drive out the center of the jig. Tap gently, as you don't want to drag the spring with the jig. It should come pretty easy.
12. With the middle section removed, you can remove the side sections. At this point, you should have the spring wrapped in the metal secured by the wire. This is where the video ends, as the remaining steps are no-brainers.
13. Throw this assembly in the oven for 4 hours at 500F. Make sure there is no plastic left in the assembly.
14. Let it cool slowly in the oven. Just turn it off after the 4 hours, and let it cool with the oven door closed.
15. Cut open the wire holding the angle metal in place.
16. The spring may jump out at you, as we only crimped it in place initially, we didn't set any angles. The coils will be offset by 30-45 degrees each. You will have to take your pliers again, and correct the angles. This is much easier than it seems, just take your time. Bend each coil down to make the sides parallel. I took three passes - one where I just got the bends parallel to themselves, then one where I got them parallel to each other, then another pass of making them parallel to themselves.
17. If you didn't wrap your spring tight enough on the jig, you may need to get a block of wood longer than the spring, put it on top of the spring, and hammer down on the wood. This can flatten the spring some, at the cost of skewing the horizontal bend angles.

Notes: I've made quite a few springs this way, and haven't failed a spring yet. It works really well in my experience. As I mentioned above, DM me @Ivanthetroll12 if you have questions or need help.