Chimera mk7 blaster with Lynx-type catch

https://www.reddit.com/r/Nerf/comments/1cz7ypo/chimera_mk7_with_a_lynxtype_catch/

This is not an exhaustive set of instructions and should be used in conjunction with the Chimera mk7 Build Guide, Printing Guide and common sense. McMaster Carr catalog numbers provided wherever necessary.

Plunger rod: 8-32 threaded rod 5.6”; 2 x flanged locknut (93298A102).  About 0.625” of bare threaded rod is exposed at the end (towards the stock).  Note that in the original design, 10-32 threaded rod is used.  It will not work with the catch I made since a flanged locknut for a 10-32 screw size will be too big for it.

Catch: Printed with 4 walls, 25% infill.  Washer for reinforcement (97725A250); 2 x catch springs (9657K644).

U Channel: 2 x 14.375” (9001K729).  The U channel I got is a little narrower than what was used in the original hardware kit.  Consequently, I had to trim the ledge that goes under the channel on the grip and receiver (after proper alignment with the cheek guard and stock). 

Al flat bars: (0.5" W, 0.125" T) 2 x 13.125” for prime bars; 23.875” for top and 7.43” for bottom (double check the top and bottom lengths in your build before cutting to be on the safe side).

Plunger Tube: 3.625" (8585K207)

Threaded Rod: (for trigger mechanism) 2 x 13.5".  I used 10-24, the hardware kit had 10-32.  Makes no difference either way as long as you use the appropriate nut.

Sealing Boss: I have uploaded two files for it — one with 2x washers and one with no washers. The former gives a slightly better performance but the prime is a little sticky towards the end as the barrel comes in contact with the washers.  Using only one washer is also okay.  Sealing Boss without washer gives a smoother prime but the seal is not perfect, but still pretty good.  A lot depends on the actual OD of the barrel so edit whichever file you use so as to match your barrel.  Printed with 4 walls, 25% infill.

I printed the cheek guard with support (chose ‘generated only from bed’ option) and it took some scraping and filing to get it cleaned up.  I applied light grease to the surfaces that come in contact with the catch.  These include the cheek guard, stock and actuator.

As seen in the second photo, the rod guide (orange) is inserted into the stock plate (green) from the inside.  Note that the hole in the rod guide is not in its center but is a little towards the top.  This piece is critical for the trigger to work.  In the original design of the plunger rod, there’s an acorn nut at the end which, I believe, serves a similar purpose as the rod guide.  I used the exposed part at the end of the rod in my design to grip the rod with pliers to tighten the lock nuts.  This ruined the threads so I could not screw an acorn nut at the end so had to design the rod guide.