How to make a Rainbow Catch

Hello readers,

My mind has been elsewhere for the past week. Something in that clean Adirondack air made me take a good look at life and make a few tweaks. Not to worry--I'm not quitting modding, just making a few adjustments. T da B has always been a musician at heart, and he has decided to dust off the old bass guitar and get thumping once again!

Let us shift back to the topic at hand: the Rainbow Catch. Invented in 2010, it was the successor to the Plusbow Catch. Its purpose was to do away with the latter's bulky side plates and be completely contained in the plunger tube. You can find templates on Nerfhaven.com, but only for the original size that fits in 1 1/4'' PVC. The Rainbow Catch that I am building is intended for 1 1/2'' PVC, so I had to do it myself with no templates. Life isn't just cutting and pasting!

The original Rainbow

Required Materials: 

• 3/4'' 6-32 pan-head bolt x2
• 6-32 nylon spacer x2
• 1/4'' polycarbonate sheet
• 6-32 shoulder screw
• Small, strong spring

Write-up:
I didn't have the patience for my crappy hole saws, so I cut off a thin sliver of 1 1/2'' PVC pipe and used the inner rim to mark three circles on a sheet of 1/4'' thick polycarbonate. I then cut the discs out with my scroll saw. My first disc sucked balls (middle), so I decided to use that piece for the middle moving piece that will be cut smaller. My second disc (right) proved slightly better, but still not perfect. It fits in the pipe, however. My third disc was pretty bad-ass; highly circular and slightly too big for the 1 1/2'' PVC--a perfect candidate for my ghetto lathing method!

For those that don't remember my ghetto lathing method: I first drilled a hole through the middle of my best disc with the 9/64'' drill bit. I then took a 1'' 6-32 bolt, inserted it through the hole, and tightened it with a nut. Then I inserted the bolt into my drill press and used my Dremel to file down the sides of the disc as the drill chuck spun. As you can see, the result is perfectly round. Fatherly wisdom passed down to me! As an additional bonus, the hole will end up perfectly centered. Take your nylon spacers and put them on either edge of the disc and mark two dots.

Now it's time to take the companion disc and get it lined up with the perfect disc. Pack them both into the pipe and then dump the centered remains onto the drill press bed (perfect disc on top). Drill through the existing 9/64'' hole with the same drill bit and get a centered hole for its companion. Test the fit with a 6-32 bolt:

Now it's time to drill the holes for the bolts that hold the catch together. Align the discs with a bolt like in the picture above, then use the 7/64'' drill bit on the holes you marked previously. The perfect disc should have its holes threaded with a 6-32 tap. The non-perfect disc should have its holes widened with the 9/64'' drill bit.

Time to widen the holes in the middle of both discs. I did them both at the same time using progressively larger drill bits until I got to my 1/2'' bit. The holes may need to be widened with a Dremel to fit the plunger rod, but you can use it to your advantage to center your hole better.

Now for the sliding piece. The two dots on the far left and far right mark the boundaries of the nylon spacers--they serve as the left and right boundaries. I then marked a dot in the very middle and traced a circle around the plunger rod centered 1/4'' below the middle dot.

Drill out the hole like the others. Notice my correction to the top of the sliding piece.

Time to scroll her out! I then used a Dremel with drill bit attachment and a flat file to get things properly carved out. Make sure the plunger rod passes through easily. Drill and tap the bottom of the piece with a 7/64'' drill bit and 6-32 tap.

At this point, all that is left is assembly! Join the circular guides with 3/4'' 6-32 bolts and nylon spacers. By only threading one set of holes, you can insure that the spacers spin and the sliding piece isn't constricted. The sliding piece should receive a 6-32 shoulder screw with a strong spring, and that should do it!

And there you have it--one Rainbow Catch made with no templates! The process isn't quite finished, since you still have to attach it to the plunger tube and drill a hole for the sliding piece. However, the hard part is done. Expect to see this in my Longstrike very soon! I hope you guys enjoyed this write-up.

~T