Project: Spump

What is old is new again!
Sometimes you have to keep pushing the envelope with all of your skills. To date, Project: Spump is the accumulation of all my talents and skills into one place. Stacked tube blowback tuning (Spyders, specifically...), light machining and metalwork, 3D modeling, and 3D printing are some of the things I'm bringing to the table. While this won't be a tutorial on how to build a Spyder Pump, it will only be a chronicle of things I did to make this a reality.
So for the uninitiated, this is how a Spyder works:
As you can see, the 2 main parts are in the upper and lower tubes. Upper is known as the bolt, lower is the striker. Both are connected by a pin between the 2 parts. As they both move forward, the striker will hit the poppet/valve stem. Once it does that, the air will flow up the valve from the bottom tube to the top, launching the ball and resetting the internals with some extra air traveling back through the valve. Blowback. The concepts behind converting this to a pump is to take away the rigid connection between the bolt and the striker while still being able to recock the striker without blowback from the valve. The next best animation to show how accomplish this, is a PGP marker.
The pump handle brings both the bolt and striker back to firing position. Pump handle moves forward and brings a ball into place. Pulling the trigger will release the striker into the valve and bring air into the upper tube to launch the ball. Note how there is no blowback action that will reset the striker. 
This is the challenge.
Following so many resources on the web, the primary source is with Vike's guide. With this and the variety of other guides, there are no set instructions on how to get your pump handle created, or how to fabricate your pump rod, or if you need a backblock. They give you concepts and examples of existing completed projects. They make you think about making calculated decisions about your build.
Similar to those that lived through the Golden Age of Paintball with Spyder owners, tricking out and individualizing your marker was a right of passage. I just saw this as another avenue to continue this same path with the piles of Spyders I've customized since the late 90s. This is where my newer skills come out to shine.

3D Design

First printed version of the backblock
First I thought I would just get an existing pump handle off of Thingiverse. I really liked the Twisted Pump Handle for the Empire Sniper. It was under barrel, like I wanted, but none of the measurements worked for me to print and add right to the Spyder's dimensions. If I had to go through remeasuring and reworking an existing model, I'd rather do that kind of work on my own piece.

The Backblock

Before I took on the design work for the pump handle, I decided to go a bit easier with making the backblock. Strategically, this was the best thing to do since I had to measure travel of the rear cocking bolt. The process of  measuring the travel by slowly pulling the bolt back and waiting for the sear to click, ready for cycling, over and over was imperative to making sure that the spacing was proper. Also taking provisions on how far forward the bolt moves to engage the striker to the poppet was the other thing to measure repeatedly. This brings us to the thickness shown in the pic to the right. That has never changed with all the newer versions. Along with that, the cotter pin location never moved!

Pump Arm Rod Guides

Next up was the gratuitously large pump arm connecting rods guides. Some decisions had to be made when designing for the the pump arm connecting rods. Does it needed to be rods or rod? I didn't want to multiply the stress on the backblock only at 1 point of contact. (Yes, I designed it with 2 lobes for 2 pump rods...) Obviously, I decided on 2 rods. Original designs carried almost all the way to the end included roll pins to guide 1/8" steel rods. It seemed to slide without any issues. (I jinxed myself. More on that later...)

Pump Handle

Almost final version!
It's time! I wanted to design this with an over-barrel design with under-cocking. This design choice was to help ensure that the 2 pump rods won't endure 100% of the stress and end up bending out. The barrel would bear some of that weight. In theory, the 2 rods locked in with the center guide rod coming from the ASA should give enough support in 2 different lateral directions. Technically, the center rod guide wouldn't have been necessary but the addition of the return spring helped with avoiding double feeds, like most pump markers come equipped with. A fun little cheat I did with the grip of the handle was to add threading. This made it a simple to way to add a texture without making raised rings and multiplying the dimensions along the body. It's very functional and it looks good!

3D Printing

Top - Original Twisted pump handle
Middle - 2 backblocks and part of the railguide
Bottom - Soooo many pump handles!
Iteration is the name of the game! Print some chunks out to test for fitment. Make design adjustments. Print again. Once that's close to being dialed in, print a full piece and see where it goes! There is so much you can learn with iteration. It's not different levels of failure, you get the chance to improve on what you've already set into motion. Every step is better than the last! All of these iterations pushed my design into something that I had to wrestle with for days. Should I continue working with the steel rods and thread/tap the ends? Should I cheat and get some lengths of threaded rod to make it easier to complete this project? I chose to go with the threaded rod. While easier to work with, it wasn't about cheapening out the design process. It was about what makes it right with rapid prototyping into a functional piece.
Who doesn't love an animated gif?

Working the Metal

Slotting the striker

The last 2 items to make this thing a reality was to mod the striker and the poppit valve stem. Hand milling out the hardened steel striker wasn't an easy task. I purchased a drill press vise to put on the deck of my press. Mounted the vise, clamped in the piece and put in the right sized drill bit. This just wasn't working. No amount of cutting oil and changing out bits gained me any type of headway in dropping holes into this piecer. Other people on the web state that it's pretty impossible to do it this way and to just use reinforced  cutting wheels on a Dremel. Switched to that and about 20 minutes later, I had striker with a hogged out channel for the bolt to ride along, but still act independently! (OMG, we are so close!)

Modifying the vertical ASA

Having the tools to do the mod, I drilled out the restrictive brass filter and widened out the whole air path for lower pressure operation. The front face of the ASA was drilled and tapped for the guide rod and return springs.

Removing blowback

Last major step in this project is to mod the poppit valve stem to all the air routes up through the valve into the upper tube to launch the ball. This will also eliminate the blowback so the striker doesn't automatically cycle back for the next trigger pull. Sources say that you can buy a new valve assembly from a set of specific Autococker aftermarket parts or you can just use JB Weld and sand it down. I went with the latter with a twist! I ended up using the mini lathe that I purchased earlier this year to make bentwood rings! I slathered the epoxy on the flattened side of the pin and let it set overnight. The next day, I chucked it in the lathe and gently shaved it down with precision. 

Test Run

Successful day at The Siege!
Once all of the bits and doodads were finally delivered, it was time to assemble the whole thing, air it up and see if it would cycle. My PMI reg was leaking like it was nobody's business. (more stuff to order...) Screwing on the bottle directly into the ASA, I could cock the striker back and slide the handle back forward. The trigger pulled and the striker slammed forward into the valve and stayed there! NO BLOWBACK! This was an exciting time. All that was needed now is to go do a stress test at an actual Paintball field. Minus the comedy of errors that ensued on the way out to the field, the marker performed beyond expectations! Even though regulator failure happened, it worked amazingly with a lower pressure bottle directly connected at 800psi, rather than the average 1200psi on Co2.

Embracing The Aesthetics

Sanded, Stained, Painted. Just needs a few topcoats!
Having gone with the 3D printed parts in red and being happy with the performance of the current setup, I decided to go against the idea to try out hydrodipping my parts with a faux arctic camo. Seeing all the black and red, it occurred to me that I could try out printing some new .45 grip covers in wood PLA. While I really love the Dye Carbon Fiber Grip Panels, I really wanted to push that personalization envelope. The word is that you can sand and stain wood filament and guess what? YOU CAN! Just be sure to keep in mind that since it's not 100% wood, you have to wait till the wood particles that are in there get as much time to soak it in and dry. Don't rush that step!

The Reveal

For about 2 months of work and loads of iterations, Project: Spump in it's current form!
There are still items to change, but this is how it will stay for some time. The biggest change will be the rail guides to lower the amount of material used and the location. The pump handle has already gone through some additional changes but won't be printed till this one hits critical failure. Below is a list of the primary parts used for this build.

Body Update:
I've been sitting on a donor Icon X for project parts. Since it's a 100% Spyder clone, it just made sense. It still houses all my mods but also allows me to delete the rail guide. (After shooting it for more than a year, the dual pump arm setup really didn't need the big, chunky, rail guide.) This body swap gives me vert feed and a ball detent. In time, I'll swap the plastic sight rail for a 3D printed Phantom Picatinny rail too.

Build List

  • Body - Spyder Compact Icon X Vert Feed Body
  • Vertical ASA - Modified Spyder Compact (no LPC)
    • Tapped and threaded for pump guide rod
    • Drilled out for lower pressure flow
  • Pump Handle - GameBlips Pump Kit
  • Pump Rods - 1/8" threaded rod, 2 - 1 foot lengths
  • Back Block - GameBlips Pump Kit
  • Rail Guide - GameBlips Pump Kit
  • Barrel - Smart Parts 18" Teardrop Big Daddy
  • Bolt - Modified stock
    • Venturi plug removed for smoother airflow and low pressure
  • Striker - Modified Slim Striker
  • Grip Frame - Spyder TL
  • Grip Covers - Invictus Cosplay Deadpool Grip Covers
    • 3D Printed
    • Sanded
    • Stained
    • Painted
    • Sealed
  • Drop Forward - Taso Mini-Drop
  • Bottom Line - Stock Kingman Spyder Sonix Offset Duckbill
  • Regulator - PMI Pure Energy Vertical Regulator
  • Ball Detent - GameBlips Ball Detent
    • 3D Printed in TPU
  • Butt Plate - GameBlips 9oz Butt Plate w/TPU ball cap
  • Hopper - Revolverloader v2
    If you think you can handle this, go make one for yourself! Share your creations! If you are looking to build one, take some of my design cues and consult Vike's Spump Tutorial to get yours started!

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