Rainbow 2 Part Plunger Rod

These are some parts I whipped up for the Rainbow/Rainfaux to print a full length blaster on my Ender 3. The full length plunger rod is too long for my print bed, so I've turned it into a 2 part assembly with a ¼-20 threaded rod running through it to hold it all together and provide rigidity. Conveniently, this threaded rod also replaces the bolts on either end of the plunger rod to retain the pullback handle and hold the seal on either end. To hold these on, I'm using 2 ¼-20 nuts each on either end of the threaded rod, with one nut being used as a jam nut. I've included a pullback handle that has space for these 2 nuts to nest in the handle without protruding into the actual grip area.

In keeping with the ethos of the Rainbow/Rainfaux, these models are open source and completely free to use. I've included the .stl, .step, and FreeCAD files so you can edit these parts however you need to serve your purposes. (I made these FreeCAD files in a weekly dev build of FreeCAD 0.22, so I don't know how they will fare in FreeCAD 0.21. 1.0 should be releasing in a few weeks, which these files should be fully compatible with. In the meantime, a weekly dev build should do the trick.)

Pictures are screenshots of the FreeCAD assembly. Hopefully they make sense for anyone trying to build this version of the plunger rod. When I print another plunger rod, I may add photos of it. For now, only the FreeCAD photos will have to do. If you're having trouble, leave a comment and I'll do my best to help.

Parts List

• 15" ¼-20 threaded rod 
• qty 4 ¼-20 hex nuts
• qty 1 5/8" OD, ¼" ID steel washer

The full length Rainbow plunger rod is too large for me to print on my Ender 3, so I've split it into a 2 part assembly with a new pull handle to accommodate my print volume.