Releasing my AR-15 Pistol Arm Brace for all to enjoy. Yes, this works on a real, actual gun. I am currently testing on a .300 AAC "Blackout" build.
No supports needed unless you have big problems with easy angles and small bridging. All files have been plated for proper/intended orientation.
There are several braces provided, however there are only four options for you to decide.
1) Plain, basic reliefs or reliefs with screw holes for vanity insert plates? Plain/Reliefs/Inserts are part of the file name.
2) Angular or Radiused? Sharp, angular corners or smoothed over/rounded edges? Each type is defined in the file name with 'angular' or 'radius'.
3) Strap loops? Only the ones with strap loops are labeled 'strap'.
4) Buffer tube diameter. I have provided every design version in 1-1/8" and 1-1/4" buffer tube size. All 1-1/8" are labeled '125Tube' in the file name and all 1-1/4" are labeled '250Tube'.
Required parts for basic function:
1x - Printed pistol arm brace of your choice.
1x - Printed Jam Insert - The little printable hex thing. This protects the buffer tube from the clamp screw.
1x - 3/8-16 x 1" socket head cap screw - This is the clamp screw. 1/4" hex "Allen" drive. Note that a 3/4" long screw will work, but ONLY FOR THE 250Tube (1-1/4" buffer).
1x - 3/8-16 nylock nut - Retains the clamp screw.
I recommend you print the TestCrossSection STL file in your sized buffer in order to verify your printer will print all the critical dimensions close enough to fit the hardware and your pistol buffer tube. It's cheap insurance before printing the whole arm brace.
When installing the nut and screw, I hold the nut with one finger close to the correct location and bring the screw in to catch the nut threads. Then make sure the nut is rotated right so it gets pulled all the way in correctly. The nut might fit a little snug, but should not be super tight.
Seat the nut fully then back out the screw about 3/8". Now pop the Jam Insert into place. It should sit flush in the buffer hole of a 250Tube, and will sit a few mm down in the hole in a 125Tube. Be sure you turn the Jam Insert correctly because the top is radiused to match the buffer tube.
Install the assembled brace on your buffer tube. Make sure it is in line vertically and clamp it with the 1/4" drive 3/8" clamp screw.
Even with the brace all the way up the buffer tube against the buffer nut you should be able to cycle the charge handle fully.
Install a strap if you're so equipped. This first release is for a 1" (25mm) strap.
Required for side plate inserts:
Your choice of printable inserts. I have provided each insert as an individual as well as paired for left and right.
4x - M3x5mm flat head tapered screws - 2 each for the Upper Inserts. Your choice of drive.
6x - M3x8mm button or cap head screws - For the Lower Inserts. Your choice of drive.
Alternatively you can print thin versions of the Lower Inserts and use (just cut 1mm off the top of each insert prior to printing):
6x - M3x8mm button or cap head screws - Your choice of drive.
6x - M3 nuts - A little more secure and they add to the utility/hardware look, if you are into that.
You should be able to use metal screws and force them to cut...or swage/press their own threads in the holes as printed. Or you can run an M3 tap in the holes, carefully.
Cosplay and weekend paintball warriors will likely be OK with just screws holding the upper inserts on, but if you are serious about them staying put I would recommend you use a plastic cement and CAREFULLY apply a little glue to the middle section and near the screw holes to bond them to the brace body.
Want a different logo or wording? Feel free to drop a comment or a message about custom inserts, or maybe I will post sketch dimensions for the Upper and Lower Inserts if there is much interest.