Nerf Tactical Rail Reel Author: Jeremy Bruck Date: Jan 20, 2016 Prepare for your next Nerf insurgency with this Tactical Rail Reel! It is intended to be used with a grappling hook or other Dart that you wish to retrieve. Point, shoot, and wind in your prey. The print incorporates a few interesting features. There is a oneway ratcheting mechanism that keeps the Spindle from spinning freely (It can be released with a lever on the side.) The Mount has ridges on the underside so that it snaps in position on your Nerf gun’s tactical rail. The knob incorporates a planetary gear (uses Emmett’s Gear Bearing and customizer) so that cable retrieval is 3x faster than turning the Spindle directly. And a cable guide that can be used when winding in your line. PARTS You will need the following parts to assemble the Nerf Tactical Rail Reel. ◻ 1x Spindle (printed) ◻ 1x Mount (printed) ◻ 1x Guide (printed) ◻ 1x Latch (printed) ◻ 1x Axle sun gear (printed) ◻ 3x Planet gear (printed) ◻ 1x Sun gear (printed) ◻ 1x Knob ring gear (printed)
PART PREPARATION Print all the needed parts. I have been using PLA but it ought to work with other materials. Also note that I am using Slic3R to generate GCode and thus dimensions are adjusted for it and my printer. No additional support structures are needed. Remove the support structure found in the mounting holes for both the Spindle and Knob. I use a drill bit. You will also need to clear the support in the three bolt holes found in the Mount. Cut the spring to about 9mm in length (I use a ballpoint pen spring). ASSEMBLY The full assembly instructions are captured below.
1) Place the spring and then the Latch into the slots found on the Mount. While holding these in position, install a 14mm M3 bolt from the underside. This bolt will thread directly into the plastic so be careful not to overtighten. When properly assembled, the latch will
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move freely but limited to about 2mm of travel at its tip.
2) Press the two bearings into both sides of the Mount. These should be a secure fit and flush with the surface.
3) Install three 20mm M3 bolts and nuts into the Mount as shown. These will serve as fixed axles for the planetary gear inside of the Knob.
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4) Press an M3 nut into the backside of the Sun Gear.
5) To assemble the planetary gear system, first drop in two of the Planet Gears into the Knob 120° apart. Be sure that the gear teeth align properly (they will only fit one way). Place the Sun Gear in the middle (with the nut facing the Knob. Place the last of the Planet Gears opposite the others.
6) Place the Axle Sun Gear into position. The assembly will be loose but should spin.
7) Slide the Knob assembly gear mount assembly. The Axle slides into the bearings and Planet Gears slide onto the 20mm bolts. This can be bit of a troublesome fit. I find that
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by rotating the Knob while pressing it into place helps.
8) Slide the Spindle onto the end of the Axle. Then slide a 40mm M3 bolt through the Spindle and tighten (it should engage the nut imbedded in the Knob Sun Gear). The Knob and Spindle should spin freely in one direction only. If it binds or does not spin well check the Axle length it may need to be modified for your setup.
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9) Secure the Cable Guide with two 6mm M2 bolts. Be careful not to over tighten as these thread into the plastic.
10) Thread one end of your cable (thread, fishing line...) to a Dart or grappling hook. I use a Dart with suction cup. To thread it I use a long thin wire and pull the thread up through the center of the dart and out through the side right near the tip. I then tie it around the suction cup. (Pulling the thread out the middle of the Dart will help with maintaining reasonable flight.) 11) The other end of the cable can be threaded through the hole in the side of the Spindle. Tie this in a knot to secure it. Done !! ALTERNATE ASSEMBLY I have provided files for an alternate version that is simpler. It replaces the planetary gear mechanism with a solid knob and uses generic 608ZZ bearings (as used with skateboards). For this version, use the alternate knob, mount, and axle. Skip step #3 where the three 20mm bolts are used. Also note that you will need to press an M3 nut into the backside of the Knob instead of the Sun Gear. And the main retention bolt is 5mm longer.
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The Alternate parts list ◻ 1x Spindle (printed) ◻ 1x Mount alternate (printed) ◻ 1x Guide (printed) ◻ 1x Latch (printed) ◻ 1x Axle alternate (printed) ◻ 1x Knob alternate (printed)
USAGE A) Attach the reel to the tactical rail of your Nerf Gun. It will snap and hold into a position. version 1.0
B) Ensure that the thread/cable from the reel is NOT slipped through the cable guide. For the cable to unspool during a shot it needs to pull free over the front of the Spindle (just like a fishing reel). C) Load the Dart. Best performance will be achieved if the cable is fed through the center of the Dart and out the back. This means that when you load the Dart, the cable will doubleover the outside of the Dart in the gun barrel. D) Fire. E) Feed the cable through the cable guide and reel in the dart. (The knob turns in the direction of the arrow printed on it.) F) If you need to release the cable while still using the guide, simply hold the release lever forward. G) With your Dart recovered you can store it in the clip on the side. PLANETARY GEAR For me, the planetary gear was bit challenging to get the clearance proper for my print resolution and Slic3R. If you wish to tighten these and improve on the design, the parameters I used with Emmett’s Gear Bearing customizer were: number of planets = 3 number of twists = 1 number of teeth on planets = 9 tolerance = 0.5 approximate number of teeth on sun = 9 pressure angle = 45 thickness = 10 diameter = 36 KEYWORDS Grappling hook Reel Nerf HISTORY Version 1.0 initial release