All of these variations are BASED on the M-LOK system by Magpul.
Please support the DEVs
I have included the 3, 5, 7, 9, and 11 Slot rails. I plan on developing the Cantilever and other commonly used mounts as well. I have used 8-32 (1/2" or 3/4" round [button] head) (3/4" or 1" flat [countersunk] head) phillips head screws and nuts to secure these to my hand guard. A 10-32 1/2" or 5/8" screw will work but may require some additional material removed from the rail so the screw can pass through the rail. A 10-32 will grab the included T-nut quite well from testing. A Hex nut may be large enough to allow for modification so that some material from the mating face can be removed and allow for it to lock into the rail with an oval footprint.
** I used a #10-32 x 3/4" flat head phillips(countersunk) for use with the tnut. as you can see in the photos there is a bit of thread left over so shorter is a acceptable but i wanted to make sure that i had positive thread engagement.
I am not staking claim or utilizing the trademark to my advantage in anyway, just a way for you to find this.
I borrowed the T-nut and used the 5 slot as a template to cut a majority of the work away. Thanks User Ripper121. http://www.thingiverse.com/thing:1827154
50% infill with 115% modifier
Supports are required to get the lift and bridging, infill amount is subjective. i have had very strong prints using PLA with this infill level.