19 replies to this topic

[Lucian]

Hello again Nerfhaven, today I’ll be showing you how to give your Ultimator a clear plunger tube, minimize the dead-space, and get it to work with a normal compression spring.

Please refer to the write up and the Mcmaster list at the bottom of the page for a materials list.

Step one.
Get your Ultimator

And open it up


Step 2.
Take the barrel and spring

And put them aside

Step 3.
Order a 1’ section of 2.5” ID 2.75” OD Polycarbonate tubing, a pack of K14 springs, and a 2” to 1/2” PVC reducing bushing from Mcmaster


Step 4.
Slap a large metal washer in front of the priming-mech to protect the plastic (Ignore the [k26] spring)


Then go ahead and slide on a cut down K14 spring and bolt the plunger head back on

Step 5. Machining the Plunger tube.
First, cut a slot on the top and bottom of the plunger tube, using the stock one as a guide. I did this using my Band-saw.

The slots were 1.25” wide, on both sides, and went down about 1.75”

Then you will need to line up the plunger tube for the 2 holes on each side that secure the plunger tube to the gun
And drill them out with a 3/8” drill bit

I screwed this part up a bit and had to widen the holes.

[Lucian]

Step 6.
Assemble the gun, tape the bushing, bolt it in, and slap a hopper on it


Alternatively, you can keep the stock spring, and just use the clear plunger tube for a striking visual effect


And for those of you that are curious, this is how the Ultimator catch system works

Issues with this mod:
The Ultimator was able to send a Slug dart 115’ in about 8-10 pumps, however I came across the issue of the plunger rod gradually slipping forward. Maybe some fine tuning will correct it, but be aware of this issue if you decide to do the mod.

Mcmaster-Carr #s:
Plunger tube- 8585K341 1 Ft. Polycarbonate Round Tube, 2-3/4" Od, 2-1/2" Id, 1' Length, Clear

Plunger Tube Bushing- 4880K172 1 Each Std-wall (schedule 40) White Pvc Pipe Fitting, 2" X 1/2", Hex Bushing, Pipe End Male X Socket F

K14 Springs- 9637K14 1 Pack Continuous-length Compression Spring, Spring-tempered Stl, 11" L, 1.093" Od, .105" Wire

Feel free to post and questions, comments, and concerns. I hope this write up was worth your time to read.

[Kid Flash]

That is some great work... Very clean. Now I need to add an ultimator to my buy list.

[jaybo1996]

I must be wrong, but from the looks of the catch mechanism, is the plunger rod held back by just friction? that can't be right.

[Galaxy613]

I must be wrong, but from the looks of the catch mechanism, is the plunger rod held back by just friction? that can't be right.

Haha, it is pretty crazy isn't it?

Snazzy mod Lucian!

[MavericK96]

I've got an Ultimator, but no real desire to do this mod, although it is pretty sweet.

Maybe I'll sell it, though the shipping would be murder...

[Jtest]

I must be wrong, but from the looks of the catch mechanism, is the plunger rod held back by just friction? that can't be right.

Lucian, correct me if I am wrong, but that catch looks very similar to the mechinism used on smooth rod caulk guns.

[knexpert66]

The first time I saw this I thought it was kind of interesting how it uses a pull spring.

[Eh Watt]

Oh, man. I really want one of these now...

Seriously, superb job on this. I saw this in the Mods/Paint directory, and I really wanted to see the write up, and now it's here! And I'm pleasantly surprised at how simple it is! I'd say the best part about this is the fact that it's so big. I have a very strong attraction to oversize blasters....

One question though, do you think the catch needs to be reinforced at all? I don't know much about friction catches, but that K14 is BEEFY!


Anyway, fantastic job, I hope you get great use out of this!

[shmmee]

I love my Ultimator, It's the only nerf gun i've seen with a notable recoil. I almost got a shiner from the priming handle after shooting it the first time on christmas morning. Though, it is too inaccurate to use as a missle launcher, and i've been to scared to screw up an irreplacable relic by doing anything but barrel attachments. I think i would miss the "Hummmmmm" the stock tenson spring makes after discharging.

I'm quite surprised you only get 115' (though it's still plenty of range) out of this mod. The Ultimator has a shockingly huge air cylinder. I don't know how you might test it, but how does the strength of the [k26] springs matchup to the stock spring? How does it do with fewer pumps? I'm left wondering if it's still discharging air long after the dart has left the barrel.

I once had a problem with my priming bar slipping too. I opened it up, wiped any lubricant off of the rod, and fidgited with the spring on the trigger some. (it had slipped) It stopped after that.

I am a big fan of the clear tube. That looks absolutely awsome!

[Chadpuff]

Nicely done. Funny everyone should mention the caulking gun thing cause I'm in the middle of designing a gun that uses a caulking gun in the same way the ultimator works.

[phillypretzel]

Very well done, now this a blaster with style. Out of curiosity, what is the approximate air volume of the plunger tube?

Edit: In the step one pic, "open it up" I can see approximately 8 different colors/textures of carpet in an area roughly 6' x 4'. I just wanted to point that out.

Edited by phillypretzel, 06 December 2010 - 10:52 PM.

[Lucian]

I must be wrong, but from the looks of the catch mechanism, is the plunger rod held back by just friction? that can't be right.

Nothing but friction, surprisingly.

Lucian, correct me if I am wrong, but that catch looks very similar to the mechanism used on smooth rod caulk guns.

Judging by Bob's post, and our discussions in #nerfchat.it seems to be the same system

One question though, do you think the catch needs to be reinforced at all? I don't know much about friction catches, but that K14 is BEEFY!

Not at all, it is made out of metal after all.

I'm quite surprised you only get 115' (though it's still plenty of range) out of this mod. The Ultimator has a shockingly huge air cylinder. I don't know how you might test it, but how does the strength of the [k26] springs matchup to the stock spring? How does it do with fewer pumps? I'm left wondering if it's still discharging air long after the dart has left the barrel.

I'll get back to you once I test it with a longer barrel.

Very well done, now this a blaster with style. Out of curiosity, what is the approximate air volume of the plunger tube?
Edit: In the step one pic, "open it up" I can see approximately 8 different colors/textures of carpet in an area roughly 6' x 4'. I just wanted to point that out.

With the plunger head 10 inches from the front, the volume is 49.08"^3

[TED]

You took away the coolest aspect of the gun. It shoots rockets from over the shoulder.

[shardbearer]

I like really like this mod, nice job. A stronger catch spring could solve the plunger slipping forward, and a longer barrel would definitely improve ranges. With this much air volume I am thinking maybe 2'.

I have found this beast of a spring, a tad more powerful than the K14, and half the price for 36" long. It is untested.

Edited by shardbearer, 07 December 2010 - 07:19 PM.

[Blue]

You took away the coolest aspect of the gun. It shoots rockets from over the shoulder.

It can still shoot missiles I believe, he can take out the coupler and put that attachment in. Whether he has missiles is the question, they are pretty rare.

[phillypretzel]

With the plunger head 10 inches from the front, the volume is 49.08"^3

Good lord. What length barrel are you using? Since you are moving a huge volume of air relatively slowly, I have a feeling that tuning the barrel length is the key to unlocking this monster's range potential. (not that it matters, as is this a novelty thing anyway) And just for the benefit of those that have never seen/fired one of these: how exactly does one prime an ultimator?

[MavericK96]

And just for the benefit of those that have never seen/fired one of these: how exactly does one prime an ultimator?

You "pump" the priming handle (i.e. lift it upward) about 20 times (however many times it takes for it to stop being prime-able). It's not an air pump, though, it just gradually draws back the plunger with each "pump".

[Lucian]

I'll put a video up of shooting and priming this beast as soon as my neighbor stops playing Online Poker; so my internet doesn't die every time I try to upload it...

And yes, Blue and Ted, it still shoots the original rocket, which I still have.

And I will try a new longer barrel, once I take off the extension spring.

Edited by Lucian, 08 December 2010 - 06:24 AM.

[HasreadCoC]

Would you ever consider selling these plunger tubes/springs pre-cut/couplered as a sort of conversion kit? If so how much? If I ever get my hands on an Ultimator I would sure be interested in buying.