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There have been 64 items by T da B (Search limited from 12-November 96)
#337992 The Ported Piston plunger head
Posted by T da B on 02 April 2014 - 03:02 PM in Homemades
You invented this independently. That's NOT a bad thing. It just means you could improve your powers of observation.
Thanks for the feedback, Just Smug Bob. So Nerf ports their plunger heads. That's wonderful--if you actually use stock plunger heads. What separates this design from anything Nerf has ever put out is the fact that multiple ports along the perimeter expand the seal in all directions while firing.
#337960 The Ported Piston plunger head
Posted by T da B on 01 April 2014 - 01:56 PM in Homemades
#337942 The Ported Piston plunger head
Posted by T da B on 01 April 2014 - 01:56 AM in Homemades
Hello lady and gentlemen,
After finally getting around to thoroughly testing this prototype, I'm very excited to present you all with some dope new technology that you may not have seen before! The idea is not mine, but I'm "porting" it over from our sister sport--Airsoft! First of all, let's quickly go over the advantages and disadvantages of regular old O-ring plunger heads:
Advantages:
- Incredibly cheap
- Take up very little real estate
- Easy to maintain
- Long-term reliability
- Low friction
Disadvantages:
- Sealed breeches don't allow air into the plunger (vacuum loading)
- More machining required
- Tight tolerances to get a working plunger head
The Ported Piston, or PP is a modified O-ring plunger head that eliminates the first disadvantage off the list. Here is a picture to illustrate:
Of course, you have to imagine a dart plugging up the right side of each plunger to understand the real benefits!
Writeup:
For this write-up, I'm building a plunger head for 1 1/2'' OD polycarbonate tubing out of 1/2'' HDPE (cutting board). Start by cutting out a disc of HDPE with a diameter about equal to the ID of your tubing. Mark the center and draw 3 lines through the middle (or more if you want more than 6 ports). Try to keep the lines equidistant from each other.
Drill a 1/8'' hole through the center and tighten on a 1 1/2'' 6-32 bolt. Chuck in it in the drill press (if you don't have the luxury of a lathe) and file/Dremel it down until it slides into your tubing nicely:
Now use a rough file and a small square one to get a nice hamburger shape. Make sure the track is wide enough to allow the O-ring to slide up and down a little. Test the fit in your tubing constantly!
Now mark the holes on top--mine were 1/4'' from the edge. Mark the holes around the perimeter that will meet up with the ports on top--they should be lined up with the O-ring when it is slid downwards all the way:
Now drill the holes in the top to a depth of around 11/32'' with a 1/16'' drill bit:
Now drill the holes along the perimeter to meet the previous ones. I centered the disc as best as I could in my small vise and used my drill press. I literally looked in through the upper hole until I saw the drill bit appear at the end of the small tunnel.
To see if your ports are functioning properly, blow through the hole on top of the disc. Clear out any swarf with a paper clip--it is imperative that the passages be clear of debris!
Here you can see what the plunger head looks like when you prime the blaster--the O-ring slides upwards, exposing the ports, then fresh air can flow from behind the plunger up through the ports and into the plunger tube for the next shot. The O-ring is a 1 5/16'' OD O-ring from Ace.
And when you fire, the O-ring slides backwards, covering the ports. As an added bonus, air rushing in through the top ports pushes the O-ring outwards, improving the seal!
Slapped on a plunger rod:
And into my Ported Piston Plusbow (PPP):
Final Thoughts:
After hundreds of shots worth of testing with various barrels, I'm getting the same performance out of my PPP as my skirt seal RainbowPump! Even with sealed breeches and rapid firing, there is no drop in velocity. Though this plunger head design required a lot of effort, the result is well worth it.
This was the max fps--the average was 260-270. It was achieved with a 12'' slide breech and 1.25'' #6 slugs. I hope you guys found this as awesome and intriguing as I did. No go forth and make yourselves a PP!
~T
#330652 T da B's Firestrike Overhaul
Posted by T da B on 08 June 2013 - 04:08 AM in Modifications
Now grab your 3/8'' Delrin and cut a 6'' length of it. Mark the end for drilling:
Drill and tap the business end:
Cut your catch notch 4 1/4'' from the back of the plunger rod:
Drill a 9/64'' hold through the end of the plunger rod for the priming handle:
Use your threaded rod, 3/4'' nylon spacers, and acorn nuts to build the priming handle:
The final step for the plunger rod is to make the front spring spacer. Its purpose is to prevent the front of the spring from hooking onto the plunger head and wrecking the seal. My solution is simple and elegant--what I always strive for! Lightly sand down the corners of the plunger rod in front of the catch notch:
Take your 1/2'' ID, 5/8'' OD polycarbonate (or CPVC) and cut out a 3/4'' segment. Drill and tap through the rear of the segment and the corresponding spot on the plunger rod:
Here you can see it in action, secured with a 1/4'' set screw:
Now is when this mod gets extremely hairy. How hairy? I'm talking Bigfoot and Chewbacca having a kid and that kid fucking Osama bin Laden. Yeah, prepare for some pain. The [k26] will wreak havoc on the rear section of the blaster of there isn't something blocking it. I decided to design my own rear spring stop out of 1/8'' polycarbonate--check it out!
This piece does not need to be glued into place and slides onto the plunger rod right in front of the trigger catch. Here is my fabrication process:
You will need to round the edges--look closely at the shell to see how the piece needs to be shaped. To make the square hole, I used a thin drill bit for my Dremel. Here you can see how the spring stop snaps into place:
The trigger catch will also need to be fabricated, since the stock catch is too tall to work with an aftermarket plunger rod. Here are the schematics for this one:
Like the spring stop, I first scrolled out the outline then later drilled a 3/8'' hole and expanded it with the Dremel:
Drill and tap the top center of the catch and insert a 3/8'' set screw:
Comparison with stock catch:
Whew! Now that that thing is done, all that is left is to mod the trigger. Cut a 5/16'' x 3/8'' piece of 1/4'' PVC and glue it to the trigger like so:
You may need to Dremel the trigger and/or the bottom of the catch to get the blaster to catch and fire, so test test test! Once you're satisfied with the fit, it's finally time to assemble the full plunger rod! Slide on the catch, spring stop, spring spacer, 4 1/4'' [k26] spring, and plunger head:
Time to put everything back into place, including the old LED! Yes, I found a spot above the old light housing that the LED can chill in to illuminate the plunger tube. I forgot to include the secondary trigger in the picture.
Close up the shell and screw on your 4 Keps nuts to secure the plunger tube to the shell. Make sure they aren't on too tight. Isn't she a thing of beauty?
Here a shot of the illumination:
Full compression of the [k26] spring after priming:
Final Thoughts:
It took a long time, but the end result was worth the pain. This little pistol is now truly "Elite" in every sense of the word--I may just have to make it its own personal slide breech. It shoots extremely hard--harder than some of my rifles, in fact! Have a look:
This was accomplished with my new 6'' slide breech and shitty beige Hot Rod darts--something I'm very perplexed about. To be honest, I find this velocity to be a little low--the reason I say this is because I don't think the rubber grommet is an optimal plunger head in any respect. It seals very well, but requires an ass-ton of lube and creates a lot of friction with the plunger tube walls. In addition, it falls victim to vacuum loading problems and takes up quite a bit of real estate. In the future, I will no longer use this type of plunger head and I may even swap mine out for a tradition washer sandwich, which is superior in every way.
In any case, I'm very happy with the outcome of this mod, and my segue into homemades continues. This is the first time I've ever worked with Delrin, and I can safely say that I'm never going back to Nylon. Stay tuned for more goodies
Hope you guys enjoyed this write-up!
~T
P.S. Nylon sucks balls.
#330651 T da B's Firestrike Overhaul
Posted by T da B on 08 June 2013 - 03:55 AM in Modifications
Sup guys,
It seems like the Firestrike is a pretty popular new blaster nowadays and a semi-worthy replacement for the Nite Finder. A few weeks ago I decided that I wasn't showing pistols enough love, so I decide to take one to the absolute max. This mod is one of my finest to date, and I went through a lot of trouble to get this thing functional. Here are some of its wonderful properties:
- 1 1/4'' polycarbonate plunger tube
- Delrin plunger rod
- 4 1/4'' [k26] at full compression
- 1 1/8'' rubber grommet seal
- Custom front spring spacer
- Custom rear spring blocker
- Custom trigger catch
Required Materials:
- 1 1/4'' diameter polycarbonate tubing
- 1/2'' PVC coupler
- 1/4'' PVC sheet
- 3/8'' Delrin rod
- 1'' 6-32 pan-head screw
- #6 washer
- 3/4'' fender washer
- 1'' fender washer
- 1 1/8'' O.D. rubber grommet
- 1/4'' polycarbonate sheet
- 1/8'' polycarbonate sheet
- 3'' 6-32 threaded rod x2
- 3/4'' length, 3/8'' thickness 6-32 nylon spacers x2
- 6-32 nylon acorn nut x2
- PVC/ABS solvent
- 1/8'' natural gum foam
- 1/2'' I.D., 5/8'' O.D. polycarbonate tubing or CPVC
- 1/4'' 6-32 set screw
- 3/8'' 6-32set screw x3
- 1/2'' 6-32 set screw x2
- 6-32 Keps (K-lock) nut x4
- Replacement catch spring
- [k26] mainspring
Required Tools:
- Scroll saw
- Dremel
- Drill or drill press
- 6-32 tap
- 3/4'' hole saw
Start by gutting that bitch:
Undo the gray tabs holding the two halves together to separate the shell:
Now Dremel off the part the houses the light unit. Do it cleanly, as you will be reusing it!
Here are the pieces you will need from the light unit:
Snap the shell halves back together:
Now to cover the gaps in the shell--chop down the two striped pieces from the light unit like so:
Then use the PVC/ABS solvent to weld it to both halves of the shell. Notice how I lined up the stripes--yes I am OCD like that sometimes!
Trim down the other two pieces:
And attach:
At this point it would behoove you to cut the plunger tube. 6'' is the length I went with--just long enough to keep the pistol compact:
Now for one of the most time-consuming parts of the mod--Dremeling the shell down to the fit the plunger tube. Use the plunger tube to constantly test the fit. The part right in front of the round section with the Nerf logo gets Dremeled so thin that I just cleared it out to look like an hourglass on both sides. One tip I can provide is to look straight down the front of the shell and look for a perfect U-shape all the way back to the rear of the shell.
At this point let's tackle the plunger tube. Cut down a 1/2'' PVC coupler and leave enough room for a 6-32 threaded rod to pass through:
Use the PVC/ABS solvent to permanently weld the coupler into the end of the plunger tube. As it turns out, the fit is perfect! Use a lot of solvent, as the seal must be airtight. When the solvent cures after a day, drill through the plunger tube with a 7/64'' drill bit and tap it with the 6-32 tap:
Insert the 6-32 threaded rod through the plunger tube. I used two hex nuts and tightened them together. Then I used a wrench on the rear nut and threaded it through:
Before the next step, you will need to drill some holes in the shell. The purpose of the holes is the support the force of the plunger rod, as you will see later. Here is where I drilled my holes--they are perfectly in line with the middle of the plunger tube:
You will now need to fabricate the rear plunger tube supports. They will be made from 1/4'' polycarbonate and follow this schematic:
Here they are!
Now take plunger tube and put it into place and close the shell. Make a mark on both sides through the rear hole on both side to designate a spot of importance. Then take your polycarbonate pieces and solvent weld them into place:
When the solvent cures, put the plunger tube back in the shell and close it up. Make two marks just like before--through the back holes. Drill and tap through the marks you made with the 7/64'' drill bit and 6-32 tap:
I forgot to take a picture of it, but you should insert a 1/2'' set screw into each of the holes you just made. Make sure that they don't protrude into the plunger tube or the spring will get snagged! The final step for the plunger is to cut yourself some plunger padding and insert it down behind the 1/2'' PVC coupler:
Next up is the plunger rod. Take your 3/4'' hole saw and cut a circle out of your 1/4'' PVC sheet. This will serve as a spacer that sits inside the rubber grommet:
Drill a 9/64'' hole right through the middle:
DO NOT POST! THIS WILL BE A TOTAL OF 2 POSTS!
#330669 T da B's Firestrike Overhaul
Posted by T da B on 08 June 2013 - 02:35 PM in Modifications
Not bad. Rubber grommets are a pretty good seal, though they're a pain to get right. That's why mostly no one uses them. It looks like yours is hitting the wall with a whole side of the grommet. you would have been better off using a skirt seal.
Yeah, my grommet seemed to have a perfect fit before I lubed it up, then it expanded a bit after. I have read of this happening to others as well for certain types of rubber. Skirts are nice, but they are very tall/expensive. For this compact setup I will probably stick with the tried and true washer sandwich and rebuild my plunger rod for a longer spring setup.
#333062 Stampede voltage upgrade issue
Posted by T da B on 15 August 2013 - 02:34 AM in Modifications
Other things to check:
1. Trigger catch activator spring
2. Make sure black return spring isn't caught somewhere
3. Make sure the breech isn't getting stuck in the receiver (caused my brass breeched Stampede to bump fire)
4. If you can hear the gears spinning, but the plunger isn't being pulled then your gearbox may be F-ed in the A
5. Make sure the trigger catch is in the right way
#329670 Solving the #1 Angel Breech Problem
Posted by T da B on 11 May 2013 - 05:34 PM in Modifications
Sup lady and gentlemen,
This little orange piece has been the bane of my existence since I first decided to make an Angel Breech for my Longshot. For those of you that don't know, this little orange guy is the attachment point between the bolt sled and breech--the #1 point of failure. Pretty much every brass breech mod that I've read calls for gluing this piece to your brass breech. I have tried many types of epoxy, including the one from the original breech created by ForsakenAngel24, but none of them have had enough strength to withstand my [k26] spring. In typical T da B fashion, I set out to solve this annoyance once and for all. This time, it involves fire!
This mod was actually influenced by the RC car modding community. They use K&S brass tubing to make their own homemade front bumpers, Nerf bars (hehe), etc. I did my research on soldering, brazing, and welding in addition to watching Youtube clips of people joining metals to prepare for this mod. Here is what you guys will be needing to make a bond that can withstand the [k26]:
Top left: Butane torch that can produce a flame reaching 2500 degrees Fahrenheit! This will be the heat source used to prepare the metals for joining. I went with the Blazer Stingray GB4001 and I'm very pleased with it.
Top center: Stay-Brite Silver Solder that will be used to fill in the spaces between the two metals to be joined. It is composed of a few metals, and the silver allows the joint to be stronger than the actual metals themselves!
Top right: Stay-Clean Liquid Flux--really poisonous stuff. However, it is extremely necessary for soldering since it cleans the surfaces of all oxides and causes the solder to stick.
Bottom: 3/8'' x 3/8'' x 12'' copper rod (89275K461)
You will also need a Dremel with a cylindrical grinding bit, a drill press, and cutting oil for this job.
Write-up:
Cut a 19/32'' length piece off of your square copper rod and grind down one end of it with a cylindrical grinding bit on the Dremel.
Bust out the drill press and drill a 1/8'' hole 1/8'' from the flat side of the piece. Use cutting oil to lubricate the drill bit and prevent overheating. You should also grind down the top of the nub at this point to fit the bolt sled, but I forgot and did it later.
Now build yourself some sort of jig to hold everything in place. I also ended up wrapping a rag soaked in water around the end with the plunger tube to prevent melting. Ideally you would do this before gluing on the bottom of the old breech. Make some marks to designate where you want the nub to go and then rough up both surfaces and clean them with rubbing alcohol. Apply flux to the bottom of the copper nub and carefully put it into place. If you ground it down properly, it won't fall off. Now hit it with the flame from all sides for a minute, then touch the solder to the base of the nub and solder should flow into place due to "capillary action."
Finished product--not the prettiest but it gets the job done! Clean up any solder with the Dremel.
Here are some glamor shots with the new nub in place:
So there you have it! The greatest problem with the Angel Breech has finally been solved. The fact is, metal is just too slippery to be held with epoxy, even after roughing the bejeezus out of it. After soldering things into place, my breech will never be breaking in that spot ever again. A silver solder joint is actually stronger than the metals you are joining! Pretty legit, eh? If you guys want to read the full write-up for my Longshot, check it out at my blog. I modified SgNerf's design and managed to squeeze 300 fps out of it!
I hope you guys enjoyed this original write-up.
~T da B
#329678 Solving the #1 Angel Breech Problem
Posted by T da B on 11 May 2013 - 06:27 PM in Modifications
It surprises me a bit, but I've encountered some push back and fear when I have suggested soldering in some of the mods I've done. I had a nut soldered to a brass breech in front of a pas. As the pas was primed an attached bar would also open the breech to accept a chambered round from a clip and then close it again as the handle was returned to the forward position. I eventually abandoned it due to clip stability issues, but the breech - and the soldered attachment was solid.
The only worry I see is that the smaller surface area might tend to bend or distort the brass tube as it's placed under load of the [k26]. It's still pretty early on, but after you get a few hundred rounds through it would you mind posting an update about durability? That really does look like a good long term option though. And like you said - that soldered joint is stronger than the materials it's joined to.
Another thought - copper is insanely expensive. Are brass square tubes of that size available? Perhaps a square tube can be soldered in place and then back filled with epoxy or epoxy putty? There might be some loss to durability, but it would be cheaper. A solid steel bar stock might also be more economical.
I see what you're saying about the brass distorting--I highly doubt it will bend, but I'll post an update after warring with the LS.
As far as replacements for copper, I was unable to find anything cheaper on Mcmaster than the rod I used. Initially I wanted to just stick to brass, but K&S only makes hollow brass tubing in the desired size and I didn't want to risk the integrity of the nub. Solid steel would definitely work, but would be much harder to machine.
#329791 Solving the #1 Angel Breech Problem
Posted by T da B on 14 May 2013 - 12:07 AM in Modifications
Which isn't soldering.
Look at all the filler metals listed, and then look at solder. It's made of lead/tin, usually. He says he's using silver solder, which usually contains maybe 3% silver.
Solder requires more of a mechanical connection/joint for it to be anything close to trustworthy for putting pressure on.
From the product description of the silver solder I used:
"Five times stronger than ordinary solder with tensile strength of 10,000-25,000 pounds per square inch. Will stretch under high pressure, but not break under constant stress and is vibration-resistant."
For comparison, J.B. Weld has a tensile strength of 3960 psi and polycarbonate has a tensile strength of 8,000 to 16,000 psi.
~T
#329674 Solving the #1 Angel Breech Problem
Posted by T da B on 11 May 2013 - 05:55 PM in Modifications
This is a pretty cool mod. Good job. I know of a few other users that did a metal welded nub, though no one actually took the time to do a write up.
However I doubt your claims of 300fps. I'd like to know exactly what you did. I know it is possible using certain setups, none of which would be war usable.
Thanks for the feedback! Check out the link to my blog to see exactly what I did.
#329691 Solving the #1 Angel Breech Problem
Posted by T da B on 11 May 2013 - 09:08 PM in Modifications
@Kronos: Correct. Electrical solder for wires usually has a rosin core, meaning the flux is built into the solder itself. For this application you want the flux to be separate in order to designate the area you want the solder to stick to.
#329806 Solving the #1 Angel Breech Problem
Posted by T da B on 14 May 2013 - 02:20 PM in Modifications
What's the composition? I don't deny that there are legit hard solders out there, but it's important note exactly what you used if others are to use this as a guide.
Chemical Composition:
Sn - 94%
Ag - 6%
Solidus:
430°F (221°C)
Liquidus:
535°F (279°C)
Recommended Joint Clearance:
0.002"-0.007"
NSF:
51
ASTM:
B32 Grade Sn95
I went the soft solder route, since it was incredibly cheap. This type of solder is mainly used for high temperature, high reliability interconnect applications, and is more than enough for a [k26] as indicated by the tensile strength. Hard solder isn't the only solder that can handle a lot of stress!
~T
#331631 Replacement bbb spring?
Posted by T da B on 06 July 2013 - 02:54 PM in Modifications
- Shave down the sides of the plunger rod
- Put in a spring stop at the rear of the plunger tube. I shaved down a 9/16'' washer, like many have done before me
Hope this helps,
~T
#325856 Question to all you modders
Posted by T da B on 26 January 2013 - 05:45 AM in General Nerf
Another thing I would love to see is foam obstacles, bunkers, and objects that can be placed in a Nerf battlefield.
I don't really care about bringing back any blasters from the past--Nerf should always be evolving!
#334818 Question about u-cup seals
Posted by T da B on 15 October 2013 - 03:15 PM in Modifications
~T
#334833 Question about u-cup seals
Posted by T da B on 16 October 2013 - 03:14 AM in Modifications
#329033 PETG Sellers
Posted by T da B on 25 April 2013 - 05:16 PM in Off Topic
2044T43
It's PE, not PETG, so it's slightly weaker. However, this fits darts that have a diameter slightly greater than 1/2'' perfectly. It's also dirt cheap at $1.41 for 4 feet of it. In addition, it fits the turret holes in all Airtechs perfectly with no Dremeling or e-taping. Hope this helps!
~T
#327409 Nitefinder plunger head substitute?
Posted by T da B on 27 February 2013 - 06:08 PM in General Nerf
P.S. If your open-ended spring keeps hooking over the neoprene washer, you may need to add a "spring spacer," which is a piece of something that fits over the plunger rod and under the spring to keep it centered near the plunger head.
#325897 Modification and Paintjob Pictures
Posted by T da B on 27 January 2013 - 05:01 AM in Modifications
- 16-inch barrel made from schedule 80 PVC and polyethylene tubing
- Plugged pump
- Skewed hopper for better visibility
- Only the wye is glued in place, allowing for interchangeable barrels and hoppers
Check out the full write-up at my blog: http://nerfbuff.blogspot.com
Cheers!
~T da B
#331359 Modification and Paintjob Pictures
Posted by T da B on 27 June 2013 - 11:44 PM in Modifications
I used a combination of Dupli-color vinyl dye and Citadel Layer hand paints for the paint job. Internals are all homemade, aside from the trigger and trigger catch. Read the full write-up at my blog.
~T
#334438 Modification and Paintjob Pictures
Posted by T da B on 03 October 2013 - 01:45 AM in Modifications
#346467 Modification and Paintjob Pictures
Posted by T da B on 28 April 2015 - 10:30 PM in Modifications
It's good to be browse these forums again after a long hiatus. I've shifted all my learning efforts over to the automotive world after putting a pause on my Nerf modding, but I forgot to share my old cubicle photos from work:
The mounts are all custom made from cardboard and T-shaped pushpins
For those that care about what my mods look like nowadays:
After wiring it up along with a new fuel pump and relay, I'll be throwing in a centrifugal supercharger--should be a fun learning experience, just like Nerf!
I"ll be back someday, my friends.
~T da B
#346619 Missing my longshot's plunger catch, anything I can do?
Posted by T da B on 07 May 2015 - 10:24 PM in Modifications
~T
#346617 Missing my longshot's plunger catch, anything I can do?
Posted by T da B on 07 May 2015 - 10:19 PM in Modifications
~T
#325067 Mcmaster springs cheat sheet!
Posted by T da B on 04 January 2013 - 07:09 PM in Modifications
#322096 Mcmaster springs cheat sheet!
Posted by T da B on 29 September 2012 - 11:23 AM in Modifications
[ [k25] ]
========================================
Deflection rate = 0.8256
Max load = 31.81 lbs (14.43 kg)
--------------------
length = 1 in
spring constant = 38.53 lbs/in
max draw = 0.83 in
--------------------
length = 2 in
spring constant = 19.27 lbs/in
max draw = 1.65 in
1 inch draw produces 19.27 lbs (8.74 kg) of force
--------------------
length = 3 in
spring constant = 12.84 lbs/in
max draw = 2.48 in
1 inch draw produces 12.84 lbs (5.83 kg) of force
2 inch draw produces 25.69 lbs (11.65 kg) of force
--------------------
length = 4 in
spring constant = 9.63 lbs/in
max draw = 3.30 in
1 inch draw produces 9.63 lbs (4.37 kg) of force
2 inch draw produces 19.27 lbs (8.74 kg) of force
3 inch draw produces 28.90 lbs (13.11 kg) of force
--------------------
length = 5 in
spring constant = 7.71 lbs/in
max draw = 4.13 in
1 inch draw produces 7.71 lbs (3.50 kg) of force
2 inch draw produces 15.41 lbs (6.99 kg) of force
3 inch draw produces 23.12 lbs (10.49 kg) of force
4 inch draw produces 30.83 lbs (13.98 kg) of force
--------------------
length = 6 in
spring constant = 6.42 lbs/in
max draw = 4.95 in
1 inch draw produces 6.42 lbs (2.91 kg) of force
2 inch draw produces 12.84 lbs (5.83 kg) of force
3 inch draw produces 19.27 lbs (8.74 kg) of force
4 inch draw produces 25.69 lbs (11.65 kg) of force
--------------------
length = 7 in
spring constant = 5.50 lbs/in
max draw = 5.78 in
1 inch draw produces 5.50 lbs (2.50 kg) of force
2 inch draw produces 11.01 lbs (4.99 kg) of force
3 inch draw produces 16.51 lbs (7.49 kg) of force
4 inch draw produces 22.02 lbs (9.99 kg) of force
5 inch draw produces 27.52 lbs (12.48 kg) of force
--------------------
length = 8 in
spring constant = 4.82 lbs/in
max draw = 6.60 in
1 inch draw produces 4.82 lbs (2.18 kg) of force
2 inch draw produces 9.63 lbs (4.37 kg) of force
3 inch draw produces 14.45 lbs (6.55 kg) of force
4 inch draw produces 19.27 lbs (8.74 kg) of force
5 inch draw produces 24.08 lbs (10.92 kg) of force
6 inch draw produces 28.90 lbs (13.11 kg) of force
--------------------
length = 9 in
spring constant = 4.28 lbs/in
max draw = 7.43 in
1 inch draw produces 4.28 lbs (1.94 kg) of force
2 inch draw produces 8.56 lbs (3.88 kg) of force
3 inch draw produces 12.84 lbs (5.83 kg) of force
4 inch draw produces 17.13 lbs (7.77 kg) of force
5 inch draw produces 21.41 lbs (9.71 kg) of force
6 inch draw produces 25.69 lbs (11.65 kg) of force
7 inch draw produces 29.97 lbs (13.59 kg) of force
--------------------
length = 10 in
spring constant = 3.85 lbs/in
max draw = 8.26 in
1 inch draw produces 3.85 lbs (1.75 kg) of force
2 inch draw produces 7.71 lbs (3.50 kg) of force
3 inch draw produces 11.56 lbs (5.24 kg) of force
4 inch draw produces 15.41 lbs (6.99 kg) of force
5 inch draw produces 19.27 lbs (8.74 kg) of force
6 inch draw produces 23.12 lbs (10.49 kg) of force
7 inch draw produces 26.97 lbs (12.23 kg) of force
8 inch draw produces 30.83 lbs (13.98 kg) of force
--------------------
length = 11 in
spring constant = 3.50 lbs/in
max draw = 9.08 in
1 inch draw produces 3.50 lbs (1.59 kg) of force
2 inch draw produces 7.01 lbs (3.18 kg) of force
3 inch draw produces 10.51 lbs (4.77 kg) of force
4 inch draw produces 14.01 lbs (6.36 kg) of force
5 inch draw produces 17.51 lbs (7.94 kg) of force
6 inch draw produces 21.02 lbs (9.53 kg) of force
7 inch draw produces 24.52 lbs (11.12 kg) of force
8 inch draw produces 28.02 lbs (12.71 kg) of force
9 inch draw produces 31.53 lbs (14.30 kg) of force
--------------------
30.00 lbs of force with a 3.00 inch draw requires a 3.85 inch spring
========================================
[ K18 ]
========================================
Deflection rate = 0.80981
Max load = 26.66 lbs (12.09 kg)
--------------------
length = 1 in
spring constant = 32.92 lbs/in
max draw = 0.81 in
--------------------
length = 2 in
spring constant = 16.46 lbs/in
max draw = 1.62 in
1 inch draw produces 16.46 lbs (7.47 kg) of force
--------------------
length = 3 in
spring constant = 10.97 lbs/in
max draw = 2.43 in
1 inch draw produces 10.97 lbs (4.98 kg) of force
2 inch draw produces 21.95 lbs (9.95 kg) of force
--------------------
length = 4 in
spring constant = 8.23 lbs/in
max draw = 3.24 in
1 inch draw produces 8.23 lbs (3.73 kg) of force
2 inch draw produces 16.46 lbs (7.47 kg) of force
3 inch draw produces 24.69 lbs (11.20 kg) of force
--------------------
length = 5 in
spring constant = 6.58 lbs/in
max draw = 4.05 in
1 inch draw produces 6.58 lbs (2.99 kg) of force
2 inch draw produces 13.17 lbs (5.97 kg) of force
3 inch draw produces 19.75 lbs (8.96 kg) of force
4 inch draw produces 26.33 lbs (11.95 kg) of force
--------------------
length = 6 in
spring constant = 5.49 lbs/in
max draw = 4.86 in
1 inch draw produces 5.49 lbs (2.49 kg) of force
2 inch draw produces 10.97 lbs (4.98 kg) of force
3 inch draw produces 16.46 lbs (7.47 kg) of force
4 inch draw produces 21.95 lbs (9.95 kg) of force
--------------------
length = 7 in
spring constant = 4.70 lbs/in
max draw = 5.67 in
1 inch draw produces 4.70 lbs (2.13 kg) of force
2 inch draw produces 9.41 lbs (4.27 kg) of force
3 inch draw produces 14.11 lbs (6.40 kg) of force
4 inch draw produces 18.81 lbs (8.53 kg) of force
5 inch draw produces 23.51 lbs (10.67 kg) of force
--------------------
length = 8 in
spring constant = 4.11 lbs/in
max draw = 6.48 in
1 inch draw produces 4.11 lbs (1.87 kg) of force
2 inch draw produces 8.23 lbs (3.73 kg) of force
3 inch draw produces 12.34 lbs (5.60 kg) of force
4 inch draw produces 16.46 lbs (7.47 kg) of force
5 inch draw produces 20.57 lbs (9.33 kg) of force
6 inch draw produces 24.69 lbs (11.20 kg) of force
--------------------
length = 9 in
spring constant = 3.66 lbs/in
max draw = 7.29 in
1 inch draw produces 3.66 lbs (1.66 kg) of force
2 inch draw produces 7.32 lbs (3.32 kg) of force
3 inch draw produces 10.97 lbs (4.98 kg) of force
4 inch draw produces 14.63 lbs (6.64 kg) of force
5 inch draw produces 18.29 lbs (8.30 kg) of force
6 inch draw produces 21.95 lbs (9.95 kg) of force
7 inch draw produces 25.60 lbs (11.61 kg) of force
--------------------
length = 10 in
spring constant = 3.29 lbs/in
max draw = 8.10 in
1 inch draw produces 3.29 lbs (1.49 kg) of force
2 inch draw produces 6.58 lbs (2.99 kg) of force
3 inch draw produces 9.88 lbs (4.48 kg) of force
4 inch draw produces 13.17 lbs (5.97 kg) of force
5 inch draw produces 16.46 lbs (7.47 kg) of force
6 inch draw produces 19.75 lbs (8.96 kg) of force
7 inch draw produces 23.04 lbs (10.45 kg) of force
8 inch draw produces 26.33 lbs (11.95 kg) of force
--------------------
length = 11 in
spring constant = 2.99 lbs/in
max draw = 8.91 in
1 inch draw produces 2.99 lbs (1.36 kg) of force
2 inch draw produces 5.99 lbs (2.71 kg) of force
3 inch draw produces 8.98 lbs (4.07 kg) of force
4 inch draw produces 11.97 lbs (5.43 kg) of force
5 inch draw produces 14.96 lbs (6.79 kg) of force
6 inch draw produces 17.96 lbs (8.14 kg) of force
7 inch draw produces 20.95 lbs (9.50 kg) of force
8 inch draw produces 23.94 lbs (10.86 kg) of force
--------------------
30.00 lbs of force with a 3.00 inch draw requires a 3.29 inch spring
========================================
[ K15 ]
========================================
Deflection rate = 0.58
Max load = 39.43 lbs (17.88 kg)
--------------------
length = 1 in
spring constant = 67.97 lbs/in
max draw = 0.58 in
--------------------
length = 2 in
spring constant = 33.99 lbs/in
max draw = 1.16 in
1 inch draw produces 33.99 lbs (15.42 kg) of force
--------------------
length = 3 in
spring constant = 22.66 lbs/in
max draw = 1.74 in
1 inch draw produces 22.66 lbs (10.28 kg) of force
--------------------
length = 4 in
spring constant = 16.99 lbs/in
max draw = 2.32 in
1 inch draw produces 16.99 lbs (7.71 kg) of force
2 inch draw produces 33.99 lbs (15.42 kg) of force
--------------------
length = 5 in
spring constant = 13.59 lbs/in
max draw = 2.90 in
1 inch draw produces 13.59 lbs (6.17 kg) of force
2 inch draw produces 27.19 lbs (12.33 kg) of force
--------------------
length = 6 in
spring constant = 11.33 lbs/in
max draw = 3.48 in
1 inch draw produces 11.33 lbs (5.14 kg) of force
2 inch draw produces 22.66 lbs (10.28 kg) of force
3 inch draw produces 33.99 lbs (15.42 kg) of force
--------------------
length = 7 in
spring constant = 9.71 lbs/in
max draw = 4.06 in
1 inch draw produces 9.71 lbs (4.40 kg) of force
2 inch draw produces 19.42 lbs (8.81 kg) of force
3 inch draw produces 29.13 lbs (13.21 kg) of force
4 inch draw produces 38.84 lbs (17.62 kg) of force
--------------------
length = 8 in
spring constant = 8.50 lbs/in
max draw = 4.64 in
1 inch draw produces 8.50 lbs (3.85 kg) of force
2 inch draw produces 16.99 lbs (7.71 kg) of force
3 inch draw produces 25.49 lbs (11.56 kg) of force
4 inch draw produces 33.99 lbs (15.42 kg) of force
--------------------
length = 9 in
spring constant = 7.55 lbs/in
max draw = 5.22 in
1 inch draw produces 7.55 lbs (3.43 kg) of force
2 inch draw produces 15.11 lbs (6.85 kg) of force
3 inch draw produces 22.66 lbs (10.28 kg) of force
4 inch draw produces 30.21 lbs (13.70 kg) of force
5 inch draw produces 37.76 lbs (17.13 kg) of force
--------------------
length = 10 in
spring constant = 6.80 lbs/in
max draw = 5.80 in
1 inch draw produces 6.80 lbs (3.08 kg) of force
2 inch draw produces 13.59 lbs (6.17 kg) of force
3 inch draw produces 20.39 lbs (9.25 kg) of force
4 inch draw produces 27.19 lbs (12.33 kg) of force
5 inch draw produces 33.99 lbs (15.42 kg) of force
--------------------
length = 11 in
spring constant = 6.18 lbs/in
max draw = 6.38 in
1 inch draw produces 6.18 lbs (2.80 kg) of force
2 inch draw produces 12.36 lbs (5.61 kg) of force
3 inch draw produces 18.54 lbs (8.41 kg) of force
4 inch draw produces 24.72 lbs (11.21 kg) of force
5 inch draw produces 30.90 lbs (14.01 kg) of force
6 inch draw produces 37.08 lbs (16.82 kg) of force
--------------------
30.00 lbs of force with a 3.00 inch draw requires a 6.80 inch spring
========================================
[ K14 ]
========================================
Deflection rate = 0.74275
Max load = 54.93 lbs (24.92 kg)
--------------------
length = 1 in
spring constant = 73.96 lbs/in
max draw = 0.74 in
--------------------
length = 2 in
spring constant = 36.98 lbs/in
max draw = 1.49 in
1 inch draw produces 36.98 lbs (16.77 kg) of force
--------------------
length = 3 in
spring constant = 24.65 lbs/in
max draw = 2.23 in
1 inch draw produces 24.65 lbs (11.18 kg) of force
2 inch draw produces 49.31 lbs (22.36 kg) of force
--------------------
length = 4 in
spring constant = 18.49 lbs/in
max draw = 2.97 in
1 inch draw produces 18.49 lbs (8.39 kg) of force
2 inch draw produces 36.98 lbs (16.77 kg) of force
--------------------
length = 5 in
spring constant = 14.79 lbs/in
max draw = 3.71 in
1 inch draw produces 14.79 lbs (6.71 kg) of force
2 inch draw produces 29.58 lbs (13.42 kg) of force
3 inch draw produces 44.38 lbs (20.13 kg) of force
--------------------
length = 6 in
spring constant = 12.33 lbs/in
max draw = 4.46 in
1 inch draw produces 12.33 lbs (5.59 kg) of force
2 inch draw produces 24.65 lbs (11.18 kg) of force
3 inch draw produces 36.98 lbs (16.77 kg) of force
4 inch draw produces 49.31 lbs (22.36 kg) of force
--------------------
length = 7 in
spring constant = 10.57 lbs/in
max draw = 5.20 in
1 inch draw produces 10.57 lbs (4.79 kg) of force
2 inch draw produces 21.13 lbs (9.58 kg) of force
3 inch draw produces 31.70 lbs (14.38 kg) of force
4 inch draw produces 42.26 lbs (19.17 kg) of force
5 inch draw produces 52.83 lbs (23.96 kg) of force
--------------------
length = 8 in
spring constant = 9.24 lbs/in
max draw = 5.94 in
1 inch draw produces 9.24 lbs (4.19 kg) of force
2 inch draw produces 18.49 lbs (8.39 kg) of force
3 inch draw produces 27.73 lbs (12.58 kg) of force
4 inch draw produces 36.98 lbs (16.77 kg) of force
5 inch draw produces 46.22 lbs (20.97 kg) of force
--------------------
length = 9 in
spring constant = 8.22 lbs/in
max draw = 6.68 in
1 inch draw produces 8.22 lbs (3.73 kg) of force
2 inch draw produces 16.44 lbs (7.45 kg) of force
3 inch draw produces 24.65 lbs (11.18 kg) of force
4 inch draw produces 32.87 lbs (14.91 kg) of force
5 inch draw produces 41.09 lbs (18.64 kg) of force
6 inch draw produces 49.31 lbs (22.36 kg) of force
--------------------
length = 10 in
spring constant = 7.40 lbs/in
max draw = 7.43 in
1 inch draw produces 7.40 lbs (3.35 kg) of force
2 inch draw produces 14.79 lbs (6.71 kg) of force
3 inch draw produces 22.19 lbs (10.06 kg) of force
4 inch draw produces 29.58 lbs (13.42 kg) of force
5 inch draw produces 36.98 lbs (16.77 kg) of force
6 inch draw produces 44.38 lbs (20.13 kg) of force
7 inch draw produces 51.77 lbs (23.48 kg) of force
--------------------
length = 11 in
spring constant = 6.72 lbs/in
max draw = 8.17 in
1 inch draw produces 6.72 lbs (3.05 kg) of force
2 inch draw produces 13.45 lbs (6.10 kg) of force
3 inch draw produces 20.17 lbs (9.15 kg) of force
4 inch draw produces 26.89 lbs (12.20 kg) of force
5 inch draw produces 33.62 lbs (15.25 kg) of force
6 inch draw produces 40.34 lbs (18.30 kg) of force
7 inch draw produces 47.06 lbs (21.35 kg) of force
8 inch draw produces 53.79 lbs (24.40 kg) of force
--------------------
30.00 lbs of force with a 3.00 inch draw requires a 7.40 inch spring
========================================
#322091 Mcmaster springs cheat sheet!
Posted by T da B on 29 September 2012 - 03:35 AM in Modifications
People can feel a little overwhelmed by the number of springs on mcmaster.com--I sure was when I first started out! Eventually, I stumbled upon this post, which clearly explained how to obtain all spring properties given the weird Mcmaster constant (now changed to a rate constant) and other spring attributes. I decided to write a computer program (in Python) incorporating all the variables from Ozymandias's spreadsheet in the post I just linked.
The math was very simple--most of the time was spent making the output look pretty. My program creates spring objects that are initialized with their Mcmaster constants. I then wrote functions to print out various properties for various springs of various lengths with various compression. Say, for example, you want to find out how much power a 5 inch [k26] puts out with 3 inches of draw. You could write out a bunch of equations on paper and figure it out, or you could plug the [k26] values into my program, create the [k26] spring object, and print out all the useful data. Here is an example of my program's output for the [k26] spring:
[ [k26] ]
========================================
Deflection rate = 0.7528
Max load = 32.13 lbs (14.58 kg)
--------------------
length = 1 in
spring constant = 42.69 lbs/in
max draw = 0.75 in
--------------------
length = 2 in
spring constant = 21.34 lbs/in
max draw = 1.51 in
1 inch draw produces 21.34 lbs (9.68 kg) of force
--------------------
length = 3 in
spring constant = 14.23 lbs/in
max draw = 2.26 in
1 inch draw produces 14.23 lbs (6.45 kg) of force
2 inch draw produces 28.46 lbs (12.91 kg) of force
--------------------
length = 4 in
spring constant = 10.67 lbs/in
max draw = 3.01 in
1 inch draw produces 10.67 lbs (4.84 kg) of force
2 inch draw produces 21.34 lbs (9.68 kg) of force
3 inch draw produces 32.01 lbs (14.52 kg) of force
--------------------
length = 5 in
spring constant = 8.54 lbs/in
max draw = 3.76 in
1 inch draw produces 8.54 lbs (3.87 kg) of force
2 inch draw produces 17.07 lbs (7.74 kg) of force
3 inch draw produces 25.61 lbs (11.62 kg) of force
--------------------
length = 6 in
spring constant = 7.11 lbs/in
max draw = 4.52 in
1 inch draw produces 7.11 lbs (3.23 kg) of force
2 inch draw produces 14.23 lbs (6.45 kg) of force
3 inch draw produces 21.34 lbs (9.68 kg) of force
4 inch draw produces 28.46 lbs (12.91 kg) of force
--------------------
length = 7 in
spring constant = 6.10 lbs/in
max draw = 5.27 in
1 inch draw produces 6.10 lbs (2.77 kg) of force
2 inch draw produces 12.20 lbs (5.53 kg) of force
3 inch draw produces 18.29 lbs (8.30 kg) of force
4 inch draw produces 24.39 lbs (11.06 kg) of force
5 inch draw produces 30.49 lbs (13.83 kg) of force
--------------------
length = 8 in
spring constant = 5.34 lbs/in
max draw = 6.02 in
1 inch draw produces 5.34 lbs (2.42 kg) of force
2 inch draw produces 10.67 lbs (4.84 kg) of force
3 inch draw produces 16.01 lbs (7.26 kg) of force
4 inch draw produces 21.34 lbs (9.68 kg) of force
5 inch draw produces 26.68 lbs (12.10 kg) of force
6 inch draw produces 32.01 lbs (14.52 kg) of force
--------------------
length = 9 in
spring constant = 4.74 lbs/in
max draw = 6.78 in
1 inch draw produces 4.74 lbs (2.15 kg) of force
2 inch draw produces 9.49 lbs (4.30 kg) of force
3 inch draw produces 14.23 lbs (6.45 kg) of force
4 inch draw produces 18.97 lbs (8.61 kg) of force
5 inch draw produces 23.71 lbs (10.76 kg) of force
6 inch draw produces 28.46 lbs (12.91 kg) of force
--------------------
length = 10 in
spring constant = 4.27 lbs/in
max draw = 7.53 in
1 inch draw produces 4.27 lbs (1.94 kg) of force
2 inch draw produces 8.54 lbs (3.87 kg) of force
3 inch draw produces 12.81 lbs (5.81 kg) of force
4 inch draw produces 17.07 lbs (7.74 kg) of force
5 inch draw produces 21.34 lbs (9.68 kg) of force
6 inch draw produces 25.61 lbs (11.62 kg) of force
7 inch draw produces 29.88 lbs (13.55 kg) of force
--------------------
length = 11 in
spring constant = 3.88 lbs/in
max draw = 8.28 in
1 inch draw produces 3.88 lbs (1.76 kg) of force
2 inch draw produces 7.76 lbs (3.52 kg) of force
3 inch draw produces 11.64 lbs (5.28 kg) of force
4 inch draw produces 15.52 lbs (7.04 kg) of force
5 inch draw produces 19.40 lbs (8.80 kg) of force
6 inch draw produces 23.28 lbs (10.56 kg) of force
7 inch draw produces 27.16 lbs (12.32 kg) of force
8 inch draw produces 31.04 lbs (14.08 kg) of force
--------------------
30.00 lbs of force with a 3.00 inch draw requires a 4.27 inch spring
As you can see, you get pretty much everything you've ever wanted to know about the [k26]. My code is very simple, and it's very easy to plug in values for any cut-to-length compression spring in the McMaster catalog using Ozymandias's spreadsheet. I will now post the actual code. To run it, download Python off python.org and install it. It should already come with the IDLE editor. Just open up IDLE, paste the code in, and hit F5 to run it. Of course, you can add any springs you want. Here is the code:
#!/usr/bin/env python """ spring.py A simple spring class that shines light on the properties of Mcmaster cut-to-length compression springs. """ __author__ = "Thomas Megantz a.k.a. T da B" class Spring(object): def __init__(self, name, rate_constant, coils_per_inch, max_length, wire_diameter): self.name = name self.rate_constant = rate_constant self.coils_per_inch = coils_per_inch self.max_length = max_length self.wire_diameter = wire_diameter self.deflection_rate = 1 - (self.coils_per_inch * self.wire_diameter) self.k = self.rate_constant / self.max_length self.max_load = self.deflection_rate * self.rate_constant def print_stats(self): print '[ {0} ]'.format(self.name) print '='*40 print 'Deflection rate = ' + str(self.deflection_rate) print 'Max load = {0:.2f} lbs ({1:.2f} kg)'.format(self.max_load, self.max_load/2.20462) print '-'*20 for length in range(self.max_length): print 'length = ' + str(length+1) + ' in' spring_constant = self.rate_constant/(length+1) print 'spring constant = {0:.2f} lbs/in'.format(spring_constant) max_draw = (length+1)*self.deflection_rate print 'max draw = {0:.2f} in'.format(max_draw) for draw in range(1, int(max_draw)+2): if draw <= max_draw: print ('{0} inch draw produces {1:.2f} lbs ({2:.2f} kg) of ' 'force').format(draw, draw*spring_constant, draw*spring_constant/2.20462) print "-" * 20 def get_length_for_load(self, draw, desired_load): spring_constant = desired_load / draw length = self.rate_constant / spring_constant print ("{0:.2f} lbs of force with a {1:.2f} inch draw requires a " "{2:.2f} inch spring").format(desired_load, draw, length) def print_spring_data(): # Add any springs here [k26] = Spring(name='[k26]', rate_constant=42.69, coils_per_inch=3.09, max_length=11, wire_diameter=.08) [k25] = Spring(name='[k25]', rate_constant=38.53, coils_per_inch=2.18, max_length=11, wire_diameter=.08) k18 = Spring(name='K18', rate_constant=32.92, coils_per_inch=2.09, max_length=11, wire_diameter=.091) k15 = Spring(name='K15', rate_constant=67.98, coils_per_inch=4, max_length=11, wire_diameter=.105) k14 = Spring(name='K14', rate_constant=73.96, coils_per_inch=2.45, max_length=11, wire_diameter=.105) # Make sure to add any new springs into the list below springs = [[k26], [k25], k18, k15, k14] for spring in springs: spring.print_stats() spring.get_length_for_load(3, 30) print "=" * 40 if __name__ == '__main__': print_spring_data()
Let me know what you guys think! I hope this helps the NIC as much as it helps me in selecting my springs and cutting them appropriately. For anyone who can't handle downloading Python and copy/pasting, let me know if you want me to paste output for other springs in Ozymandias's spreadsheet. Happy nerfing!
~T da B
#322149 Mcmaster springs cheat sheet!
Posted by T da B on 02 October 2012 - 01:36 AM in Modifications
#334618 Longstrike mod: homemade internals
Posted by T da B on 08 October 2013 - 08:10 PM in Modifications
#334589 Longstrike mod: homemade internals
Posted by T da B on 08 October 2013 - 12:25 AM in Modifications
I browse the forums fairly regularly and sometimes I see something that really impresses me. In this case, it was actually a Longstrike! It's not often you get all hot and bothered by a blaster that absolutely blows stock. However, nowadays I see blasters in a different light than I used to. Now that I have the means to create any of my own components, there's no point in reusing Hasbro's internals at all. A blaster's worth to me is now measured in how good it looks and how easy it is to incorporate internals and other goodies. The Longstrike satisfies all my requirements, and just happens to have enough room for a 1.5'' PVC plunger tube! This mod is literally a wolf in sheep's clothing--the shell is the only thing left that's actually stock.
Here's the Longstrike I got for free:
The bolt was stuck, so the owner probably tried to open it up, realized it was solvent welded, and gave up. Sweet!
Required Materials:
- 1.5'' clear PVC pipe
- 6-32 threaded rod
- 1 1/4'' to 1/2'' PVC bushing
- 6-32 Keps nut x4
- 3/8'' length 6-32 set screw x4
- 1/2'' length 6-32 set screw x2
- 1/4'' polycarbonate sheet
- 1/8'' polycarbonate sheet
- 6-32 nylon spacer x2
- 3/4'' length 6-32 screw x4
- 6-32 shoulder screw
- Small, strong spring for catch
- [k26] mainspring
- 1/2'' round Delrin rod
- Spud gasket (for toilets)
- 1'' length 6-32 screw
- 3/8'' length 6-32 screw
- #6 washer
- U-cup or piston cup ()
Required Tools:
- Scroll saw
- Screwdriver
- Drill press
- Hand drill
- Dremel
Write-up:
Let me start out by saying that taking apart this blaster can be a huge bitch. There were orange pieces randomly solvent welded into place that actually kept the two halves of the shell from separating. Suffice it to say, I ended up using the Dremel as a samurai sword and severing anything in my path. I think it's a conspiracy by Hasbro to prevent people from modding blasters with too much real estate inside them. Anyways, eventually I cracked the egg. Start by cutting the plunger tube. It should be a whopping 14'' in length:
Now to prepare the front bushing. I secured the bushing in between two fender washers, tightened nuts on both ends, and put it in the drill press.
I used my "ghetto lathing" method to shave down the bushing with a Dremel until it fit nicely into the plunger tube. Use some PVC solvent to permanently attach the bushing with an airtight seal:
Now for the worst part of the mod--Dremeling the shell to fit the plunger tube. You can make things a little easier by cutting out the gloryholes that I did:
Dremeling the shell proved so frustrating that I even forgot to take a picture of it. Just keep checking the fit with the plunger tube until it fits. The front of the plunger tube should be flush with the front of the shell as well. Anyways, let's finish up the plunger tube. This requires the construction of a Rainbow Catch. I did a write-up on how to make a 1.5'' Rainbow Catch with no templates here.
Stick it in the back of the plunger tube and mark where the shoulder screw will pass through. Drill the hole with the 5/32'' drill bit, then use a small screw to hold the catch in place for more drilling.
Drill four holes with the 7/64'' drill bit through the plunger tube and into the inner ring of the catch. Tap them all.
Now that the rear end is prepared for duty, it's time to put the threaded rod through the front bushing. Drill through with the 7/64'' bit, tap, and insert the threaded rod. Drill 9/64'' holes in the shell at the front for the threaded rod. Add glue around the threads to prevent air leakage. Fail to do this and you won't get the perfect seal!
Put the plunger tube in place and enclose it in the shell. Then drill a 7/64'' hole through the shell and plunger tube on either side towards the rear of the blaster. Expand the holes in the shell with the 9/64'' bit. This step is just to insure that the plunger tube has adequate support.
Last order of business is plunger padding. I used a healthy amount of toilet gasket to kill some dead space and insure that the blaster doesn't destroy itself:
Now on to the plunger rod. Cut a 14'' length of Delrin rod and drill (and tap) one end of it with the usual 7/64'' drill bit.
Here is my plunger head. From left to right: 1'' screw, #6 washer, 1/4'' polycarbonate disc, <1/4'' polycarbonate disc, U-cup, 1/4'' polycarbonate disc.
In order to prime the blaster you need to fabricate something here is what I made:
I attached it to the end of the plunger rod with a couple of 3/4'' screws. Later I ended up trimming down the sides, since I was getting some facerape holding my head against the stock while firing.
Here is the plunger rod assembled. As you can see, my U-cup was a bit large. Regardless, the seal is perfect. I have discovered recently that 1.5'' OD piston cups plunger heads are the ideal choice for 1.5'' PVC.
Don't forget to Dremel the back of the shell for the new priming rod:
Put the assembly in the blaster and get a friend. Prime the blaster all the way back and get a friend to make a mark right where the rod leaves the shell. The front of the catch notch will be cut 3'' in front of the mark:
Reassemble everything again, and we're almost through! Here are some shots of the completed plunger tube:
Now for the final challenge--making the trigger! Obi, the original creator of this mod cautioned that this would be the hard part, but I thought about it for a while and arrived at a simple and elegant solution. First, a piece of the shell must be trimmed in order to accommodate the trigger:
Here are some tentative schematics I used for the trigger. The final product was a bit taller and wider:
Here is everything needed for the trigger setup. The trigger is 1/8'' polycarbonate, the mount is 1/4'' PC, and the screw is a 3/8'' screw.
The piece of polycarbonate is 3/8'' wide and 7/8'' tall. It has been drilled and tapped with the 7/64'' drill bit and goes here:
The rest is simple:
And the rest is history! Put it all back together (without forgetting the rail mount pieces) and marvel at what the Longstrike wished it could always be:
Cutaways are nice, so you can see full compression in action!
Conclusion:
Damn, what a blaster. It seems like even a 16'' barrel is no problem for this bad boy. With over 7'' of draw, this thing could actually put an eye out. Many thanks to Obi, the modder I followed--you are a gentleman, scholar, and general baller. Hopefully this writeup brings hope to those who have lost faith in the Longstrike. One thing I could have done better was move the priming handle closer to the plunger tube to avoid face-diddle, but it may be unavoidable with over 7'' of draw. Here is the average velocity:
Not bad, considering the plunger head is too fat. Perhaps my 16'' barrel was too short as well--I'll have to make a 2-footer for blasters like this! In any case, I'll be revisiting this blaster farther down the road for one final mod--a shotgun grip
Cheers,
~T
#334235 Longshot Bolt to Plunger Tube seal
Posted by T da B on 23 September 2013 - 07:38 PM in Modifications
Hope this helps!
~T
#326170 Log Home Help Foam questions
Posted by T da B on 30 January 2013 - 10:52 PM in Darts and Barrels
~T da B
#326191 Log Home Help Foam questions
Posted by T da B on 31 January 2013 - 03:41 PM in Darts and Barrels
Throw out the misconception that there's such a thing as general springer fit in CPVC. CPVC has an incredibly variable ID.
Right--I totally forgot to mention that I'm using "Flowguard Gold" CPVC.
^ Not looking hard enough or too lazy to heat and stretch. Post again in like 5 years and you'll have barrels for everything you need, or take the time to get the results you want today.
Too lazy would be accurate. Also, I'm moving away from CPVC--all my hoppers and slide breeches are PVC-based and none of my good darts fit Flowguard Gold CPVC anyways.
I use cheap, trashy gray foam (mixed sources) most of the time and it brings in hits. Especially in this era of slugs and metal-free alternatives, the type of foam you are using does not matter as much as it did in the era of slingshot domes.
Totally disagree. Low-quality foam will deform very quickly and lose its accuracy and fit. Also, my stronger blasters often destroy shitty grey foam darts in one shot--quality blasters need quality foam. Besides longevity, I've also gotten significant range increases by using better foam.
Now I must ask--where does one get this "Pink MHA?"
#334154 K9 Kannon
Posted by T da B on 19 September 2013 - 07:07 PM in Modifications
One more idea: you might be able to "hopper" it with just a tube that gravity feeds into the front chamber!
#334144 K9 Kannon
Posted by T da B on 19 September 2013 - 02:07 PM in Modifications
#341160 Issues with modifying an Elite Alpha Trooper
Posted by T da B on 12 August 2014 - 05:30 PM in Modifications
Hope this helps,
~T
#336200 I reproduced Stampede ECS gears, and "hello"
Posted by T da B on 31 December 2013 - 05:04 PM in Modifications
~T
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