-Drill press and power drill
-Belt Sander/Disc Grinder (used exclusively for handles; Disc grinder used to square tubes)
-Dremel w/ cutting wheel
-7/64”, 5/32”, 3/16”, 7/32” drill bits and 3/8”, ½”, 9/16” spade bits
-#6-32 tapping bit
-Scissors and/or file
-1/16" Hex driver
-Vise (very helpful)
-Computer (obs), printer, and full sheet label paper (templates)
Very helpful, not critical:
-Custom tooling plates
Cost and Parts List
The dimensions for the pumpgrip are wrong and the diagram. It should be 2" x 1 3/4" Polyester, which is correct in the parts list.
Fabrication and Assembly:
Print out your templates on label paper, cut them out, and secure them to the various materials. (Trigger not pictured, should be in wood)
Drill all designated holes with appropriate drill bits. Cut out each piece on the scrollsaw. For the the catch can be done with holesaws, I’ve heard. I've tried it before and found the closest holesaw I could find was a bit too small than I wanted for 1 ¼” PVC. So instead I just cut everything by hand on the scrollsaw. The templates are exact to 1.36” for the circles.
Assemble the two outside circles for the catch together with ¾” screws. When you’re assembling it, put the catch in between the circles so you can gauge how much room you’ll need to leave for the catch to move up and down freely. You can give it a little bit more room than it needs, and it’ll work perfectly fine. It’s better to go on the larger size than for it to not be able to move. You’ll want the circle with the ½” hole, to be on the back of the screws, and the circle with the 9/16” hole to be closest to the screw heads. Basically, ½” circle guides the plunger rod through the catch, and the 9/16” hole allows you to not have to have both holes perfectly lined up. The first circle has to have a ½” hole otherwise the spring will get caught in between the small gap between the hole and the plunger rod. Another thing that should be noted is most of the time the nylon is a hair larger than ½”. For some reason I have a few spade bits that measure up to .510” and seem to be perfect for this application. So this is something you might have to play with a bit.
Next you’ll have to make the hole where the screw attaches to the bottom of the catch. Easiest way to do this part is to have a small vise. They usually are included with a decent drill press. Position the catch in the vise as straight as possible so the screw is perpendicular to the top of the notch. Drill it with a 7/64” drill bit and tap.
Now you’ll need to drill your holes for your plunger tube. The distances for the holes are marked on the dimensions sheet, but here is the order of holes you’ll need to make. On the bottom, the first two holes used to attach the handle, are 7/64” and tapped. The next hole is 5/32” which will be where the screw passes through that connects to the catch. The next two holes after than are also 7/64” and tapped, and also for the handle connection. On the top of the plunger tube, you need to drill four 3/8” holes in each spot where there is a 7/64” hole on the bottom. You’ll need these holes to pass the screwdriver through the plunger tube to connect the handle from above.
Now, take your Rainbow catch assembly, and shove it into the correct spot. You’ll have to align the outer frame of the catch assembly with the 5/32” hole in the plunger tube, for the catch. It’s hard to explain, but you want to make sure the catch assembly isn’t cocked to the side when you secure it in.
At this time you’ll want to make your catch spring. Take a ¾” screw, put on a washer, then your catch spring, with another washer behind that. Screw it into the bottom of the catch until the bottom of the screw meets the bottom of the catch, but does not exceed that point. You don’t want that screw rubbing on your plunger rod. You’ll have to play with the length a bit but it should be short enough to it doesn’t interfere with the travel of the catch. Before this you should have also ran a piece of your ½” nylon through the catch assembly to make sure there isn’t any unnecessary friction.
Now tighten the screw attached to the catch until it doesn’t move anymore. This should keep the catch assembly in the plunger tube so it doesn’t move. Now you’ll have to drill your holes to secure it. Ideally it would be much easier to use a thicker material for the spring rest. ¼” is the absolute minimum you can screw and tap into the side of. Drill as deep as you can into the spring rest to fit the set screws. You’ll want four holes. Now you’ll have to take the catch assembly back out, then deburr, and tap both the catch assembly and the plunger tube. It’s easier to do them separately.
After you re-insert the catch assembly, add a 3/8” set screw in each hole. Put your catch spring back in and make sure your catch works. After you’ve done that, take it back out.
Put in your internal coupler, cut to the dimensions it needs to be. You’ll have to cut down the 2” end just a bit to allow it butt up against the catch assembly. When you’re cutting the internal coupler, take a ½” regular coupler, and see which side it fits tight in. For some reason, one side is much larger than the other and one side always fits ½” couplers. Make sure you’re cutting off the tighter section, so you can use it later for the bushing.
After you have the internal coupler in your plunger tube, drill out the 3/8” and 7/64” holes in the internal coupler.
Now it’s time to do your handle. I use a belt sander to carve down that big block that’s posted for the template. If you don’t have a belt sander, you’ll have to think of something else that will probably involve a lot of manual labor.
I also sanded down the polycarbonate pieces so my hand (or other people’s) don’t get diddled by sharp edges. Keep the template on your smaller wood piece. You’ll need it. Also the trigger is again not pictured. I sanded down the edges of the trigger, as well.
Mark on the block of wood in the center of the piece where the line in coming down. This will be one of the anchor points for the handle. Drill that with a 7/64” bit, and then assemble the rest of the handle together with ¾” screws in each of the holes.
Now it’s time for the worst part, fabricating the pump grip. Cut out the 2” polyester according to the dimensions sheet. The gap in the middle is where you’ll need to cut out your section. It only needs to be wide enough to allow it to pass over the handle. For this part the only tool you can really use is a Dremel. Eventually I’ll be doing these on the mill, but you’ll probably be doing this with a Dremel. You’ll also need to cut a section out from the front that will allow the pump grip to extend into the wye. This will only need to be about an inch long.
Next you’ll want to take your pump grip and slide it over your plunger tube. Center the slot in the pump grip with the holes for the handle so you pump grip will be aligned with the handle. Make sure the back of the pump grip is past where the handle will be. Now you’ll have to mark where the four 3/8” holes are for the handle. Drill these out with a 3/8” bit as well. You’ll need these access holes because the pump grip needs to be on the blaster before the handle is attached.
End of picture limit, do not post. This will be three total posts.
Edited by Ryan201821, 16 August 2011 - 03:03 PM.