Introduction: +Bow - Homemade Spring-Powered Nerf Rifle



Specifications
Length: 36 inches
Weight: 2lb
Plunger load: 18-32lb
Spring load maximum: 38lb
Optimal Barrel Length: 12 inches

Performance
Plunger rod has three notches affording different load rates which gives the user different range options.

Distances averaged
28lb Pull: 140 feet
22lb Pull: 110 feet
16lb Pull: 80 feet

Individual results will be dependent upon too many factors to list so take these only at face value.

Tools REQUIRED for following this guide
+ Scrollsaw
+ PowerDrill or Drillpress
+ Mitre Box & Mitre Saw or a power tool useful for cutting plastic rod or tube (such as a table saw, circular saw, or band saw)
+ #6-32 Tapping Bit
+ Screwdriver
+ Hobby Knife (to clean the edges of the sheets once cut)
+ Scissors

No other tools expressly needed. All tools listed are not easily substitutable and I don't recommend attempting to make this gun with anything other than a scrollsaw due to the size of the parts you will be making.

Part List
Download: plusbow_partlist.txt
Note: You will also need some full sheet label paper, electrical tape, and some spray silicone lubricant.

All items available through Mcmaster Carr

Simply search for the part #s listed. Total cost of supplies listed is around $80 plus shipping. You will have enough excess of most materials to make atleast 2 or 3 more guns.

Be warned. This guide has 37 steps. Not because the project is extremely complicated, but because I'm going to go into a good deal of detail on each step.

Step 1: Step One

Download the cuttings template sheets: plusbow_templates.doc (100kb)

Print them on full sheet label paper. If you ran out of color ink (like I did) make sure to use a colored pencil to mark the holes with the size you will need to drill them to.

Step 2: Step Two

Cut out all of the templates from the full sheet.

Set aside the labels indicated in the picture because you won't be applying them right away.

They will have to be applied to the opposite ends of the 13.25 x .5" length piece of 1/4" thickness polycarbonate that will become the plunger rod. You can cut this out now or later using a scroll saw or table saw after marking the dimensions.

Step 3: Step Three

Apply the cutting templates to the indicated thicknesses of polycarbonate sheet.

You can group them fairly close together to minimize excess, but keep enough of a gap to allow the blade of the scroll saw to cut inbetween the parts.

Step 4: Step Four

Cut the labeling sheets into smaller more manageable sections using a scroll saw or band saw.

Wait to cut out all of the small parts until later. This will make drilling holes in the smaller pieces much easier and safer.

Step 5: Step Five

Using a drill press or power drill follow the color legend you printed or wrote on the labels to drill out all of the holes to the required sizes.

Also make sure to drill 5/32" diameter pilot holes in the center of the areas you will have cut out. Such as the pass-through holes in the frame pieces and catch plate, The slide tracks in the trigger and catch plate, the trigger wells in the sides of the grip, the center of the priming handle, and the optional decorative "+" signs on the body sides

Step 6: Step Six

Use a scroll saw or band saw to make all of the external cuts needed to free and shape all of the parts out of the sheet.

Step 7: Step Seven

Use a scroll saw to make all of the internal cut outs. Start by feeding the blade through the pilot hole you drilled in Step Five then retensioning the blade.

Step 8: Step Eight

Now all of your plastic sheet parts are cut out.

Step 9: Step Nine

Using the side plates that they will eventually screw into as a guide, mark the edges of both sides of the frame pieces as shown.

Step 10: Step Ten

Using a 7/64" bit in a drillpress or power drill drill to a depth of around 1/2 of an inch. Then tap the holes with a UNC #6-32 tapping bit.

Step 11: Step Eleven

Using a mitre saw with box, table saw, table saw, or circular saw cut a 7/16" length section off of the 1" diameter plastic rod.

Using the 1/8" thickness plunger rod piece as a template (as centered as you can get it), mark the two holes as shown.

Using a 5/32" bit in a drill press or power drill drill through at the marked points.

Step 12: Step Twelve

Using a mitre saw with box, table saw, table saw, or circular saw cut two 11-1/4" length sections and one 12" length section off of the 1/2" diameter plastic rod.

Mark the center of both ends of the rods.

Using a 7/64" bit in a drillpress or power drill drill to a depth of around 1/2 of an inch. Then tap the holes with a UNC #6-32 tapping bit.

Step 13: Step Thirteen

Remove the cutting templates and protective film from the plastic sheet parts.
The catch plate will need its lower edge beveled and the corners of the stub at the top beveled to accept a spring. To see more detail on this part see Step Seventeen and Step Eighteen.

Step 14: Step Fourteen

Deburr the edges of all of the sheets using a hobby knife To quickly remove the burrs simply orient the blade perpendicular against the edges of the sheet and run it along them. Any trouble spots and be cleaned with the hobby knife by manually cutting away the burrs.
Further smoothing can be done with sandpaper if desired. I would recommend doing so on the grip.

Step 15: Step Fifteen

Using the 1/8" thickness plunger rod part as a template, mare the front edge of the plunger rod.

Using the front piece of the adapter bracket, do the same on the front edge of the side pieces for the adapter bracket.

Using a 7/64" bit in a drillpress or power drill drill to a depth of around 1/2 of an inch. Then tap the holes with a UNC #6-32 tapping bit.

Step 16: Step Sixteen

Squeeze two Dash 316 O-Rings onto the 7/16" section of 1" diameter plastic rod. Sandwich it inbetween the 1/8" and 1/4" thickness plunger head pieces and bolt them onto the end of the plunger rod using 1" length screws.

Step 17: Step Seventeen

Assemble the center frame piece and catch plate together as shown using washers and 1" length screws.

Attach the 12" length section of 1/2" diameter rod to the center frame piece using a 3/8" length screw. Mark on it where the centerline of the catch plate is.

Remove the 12" rod and using a 7/64" bit in a drillpress or power drill drill through where marked. Then tap the hole with a UNC #6-32 tapping bit.

Attach the 12" length rod to the rear frame piece again using a 3/8" length screw. Install a set screw into the newly tapped hole by hand.

Step 18: Step Eighteen

Install a 1" length spring (one with a load between one and ten pounds) onto the catch plate and the set screw.

Step 19: Step Nineteen

Attach the 11-1/4" length sections of 1/2" diamter rod to both the rear frame piece and the butt stock using 3/8" length screws.

Step 20: Step Twenty

Slide the 12" length rod through the 1/2" hole in the rear frame piece and then bolt it to the butt stock using 3/8" length screws.

Step 21: Step Twenty One

Attach the side plates to the center and rear frame pieces using 3/8" length screws.

Use one of the grip pieces as a template to mark the edges on both sides of the rear frame piece where shown.

Using a 7/64" bit in a drillpress or power drill drill where marked to a depth of around 1/2 of an inch. Then tap the hole with a UNC #6-32 tapping bit.

Step 22: Step Twenty Two

Attach the front plates to the side plates using two 1/4" length screws, four 3/8" length screws, and two 1-1/2" standoffs. Wrap and tie a rubber band onto the standoff where shown.

Step 23: Step Twenty Three

Place the plunger cross where shown inbetween the 1" screws protruding from the front of the center frame piece.

Step 24: Step Twenty Four

Assuming you order exactly one foot of the 1-3/8" ID polycarbonate tube it should already be at the length you need. If not then use a mitre saw with box, table saw, band saw, or circular saw to cut a 12" length section from the longer tube.

Slide the 12" length plunger tube onto the plunger cross and push it down to meet the top of the 1-1/2" standoffs.

Step 25: Step Twenty Five

Mark where shown.

Using a 5/32" bit in a drillpress or power drill drill where marked on both sides.

Step 26: Step Twenty Six

Insert the hex bushing adapter into the end of the plunger tube and mark it as shown as well.

You don't want to drill the holes in the hex bushing too far forward or it will prevent you from installing a barrel.

Using a 5/32" bit in a drillpress or power drill drill where marked on both sides of the hex bushing.

Step 27: Step Twenty Seven

Wrap the hex bushing in 3 or 4 layers of electrical tape then use a hobby knife or ice pick to poke through the drill holes in its sides.

Push it into the end of the plunger tube and line up all the holes. Lightly hammer then hand screw the bolt all of the way through and affix it on the other side using a lock nut.

Step 28: Step Twenty Eight

Remove the new plunger tube assembly from the rest of the gun as shown.

Step 29: Step Twenty Nine

Clean out the inside of the plunger tube then spray a generous amount of silicone lubricant into it.

ONLY USE SILICONE LUBRICANT WITH PLASTICS. It's the only lubricant that won't eat away or degrade the material.

Install the plunger rod and spring in the plunger tube. Work the plunger rod back and forth in the plunger tube a few times to get the o-rings lubricated.

Step 30: Step Thirty

While depressing the catch plate by hand, slide the plunger rod through the plunger cross, center frame piece, catch plate, and rear frame piece.

Reattach the plunger tube assembly to the rest of the gun, starting with the 1/4" length screws.
Attach the priming handle to the exposed end of the plunger rod.

You can make and attach either one or two of these depending on your preferences. Other handle options are possible, but the other methods I've tried weren't as comfortable as this one.

Step 31: Step Thirty One

Use one of the grip pieces as a template for marking the 3/4" thickness polyethylene foam sheet. How much padding extends away from the grip is up to you, but 1/4" to 1/2" is plenty.

Make sure to mark the two holes as well.

Step 32: Step Thirty Two

Finish marking like so and the foam shouldn't interrupt the trigger.

Use a hobby knife or ice pick to stab out the holes. Use a band saw, hobby knife, scroll saw, or scissors to cut out the foam piece.

Step 33: Step Thirty Three

Follow the photograph labels for attaching the hardware to one of the grip pieces.

Step 34: Step Thirty Four

Slide the foam grip core onto the standoffs. Slide the trigger piece onto the 1-1/4" length screws and add another 1/4" length spacer. Install a 3/8" length screw in one side of the trigger.

Step 35: Step Thirty Five

Add a 3/8" spacer to the opposite grip piece. Put a washer and a lock nut on the end of both 1-1/4" length screws, but only tighten them enough for them to lock or the trigger won't slide.

Step 36: Step Thirty Six

Attach the front of the grip to the side pieces using 3/8" screws as shown. Hook the loose end of the rubber band onto the 3/8" screw you installed on one side of the trigger.

Hinge the grip into place over the rear frame piece and attach it to both the rear frame piece and side pieces using four 3/8" screws.

Step 37: Step Thirty Seven

Add your preferred barrel, and your gun is now complete. The process has taken anywhere from 6 to 12 hours from start to finish depending on the tools you were using.

Final Notes:
+ This gun is extremely durable, but in the rare event something does break it's not at all difficult toreplace any of the parts.
+ This gun doens't involve any glue. Hot, cold, or otherwise. So it should be able to take heat, cold, or humidity without any problems.
+ The rubber band on the trigger isn't a vital part and the gun will still function if it were to break. It's only there to improve the feel of the trigger and could just as well be replaced with a short/weak extension spring. I didn't have any on hand.

Comments

author
skaboy (author)2010-03-11

 i'm interested in getting into this hobby and ive been looking at several homemades and i have to say yours is probably the most effective i have seen considering the simplicity of it.  kudos! I was wondering though, how hard would it be to modify your design to hold a clip or some kind of system that would allow it be fire semi-automatically? 

author
CaptainSlug (author)skaboy2010-03-12

No, it's not possible to make a spring-plunger blaster semi-automatic.

author
Titan020303 (author)CaptainSlug2016-10-02

yes it is (Stampede) for a homemade it would be extremely hard

author
Titan020303 (author)Titan0203032016-10-02

and yes I know the stampede is full auto I am just giving a general thought

author
DIYkindaguy (author)2014-03-20

Have you ever tried to measure the muzzle velocity? I'm just wondering because I'm trying to create a slightly "suped up" paintball version of the basics behind this system and I'm wondering if this could send a paintball fast enough to be effective.

author
Great Wight Ninja (author)2011-10-07

I have been wondering this since I first saw the design on Nerfhaven about half a year ago. What makes it a bow? I mean, I've even seen plenty of "crossbows" that are little more than stylized slingshots, but they actually have a pseudo-bow to them. The Big Bad Bow isn't even really a bow. It's a stylized gun as well. But again, what makes this a bow?

I realize someone just decided to name it a +bow and the name stuck, but I was hoping you/someone could help shed some light on the rationale.

This will not, however, prevent me from making the effort to finally build one of these when I have time and access to the tools.

author

It is called a "bow" because it is based off of the vintage Nerf gun, the Cross Bow.

author
Matthew1871 (author)2011-06-16

i love it but i have to thing to say Coild there be like a site wear i can get those parts that ship to CANADA because Mc Master Carr only ships to US witch sucks or ill just wait 1 year till i go to us and then order the supplies plz HELP!!!

author
armored bore (author)2011-06-01

In my vast engineering intellect, I think I cut my plunger rod a bit too short for the whole spring. Should I trim down the spring to fit it?

author
armored bore (author)2011-05-24

Are those other rectangular components still required? I can't find them on the template document.

author
CaptainSlug (author)armored bore2011-05-25

No, those are optional accessory parts.

author
natester632 (author)2010-10-18

How big should the paper be that you print the templates on?

author
CaptainSlug (author)natester6322010-10-19

Regular Letter 8.5 x 11

author
natester632 (author)CaptainSlug2011-03-22

k thx :)

author
tazer_trooper (author)2010-11-28

it reminds me of a 50cal.

author
Kikot (author)2010-10-16

waw where did u get that huge spring?

author
jongscx (author)2010-09-11

Wait... how do you load and shoot this thing? Is it just a muzzle-loader?

author
CaptainSlug (author)jongscx2010-09-11

You can add whatever type of barrel or breech you want. Hopper clips, speed-loaders, or slide breeches.

author
popscott3 (author)2010-06-09

THAT IS SO COOL!!!

author
Ghost Wolf (author)2009-04-04

where does the amo go? or is there a clip

author
CaptainSlug (author)Ghost Wolf2009-04-05

It uses whatever barrel type you want to plug into the bushing adapter. The design doesn't explicitly include a breech or clip.

author
eleven-seven (author)CaptainSlug2010-05-26

how much was the plus bow to make?

author

could you, or do you know where i could find, a list of parts that i should get to make this

author
CaptainSlug (author)eleven-seven2010-05-27

It's in the first step of the instructable as a text file link.

author
Ghost Wolf (author)CaptainSlug2009-04-05

ok thanks

author
Airsoft Guy (author)2010-04-27

 now i just need the petg plunger tube

author
Airsoft Guy (author)2010-04-20

 i just need the catch and k26 spring can i just buy those off you please

author
CaptainSlug (author)Airsoft Guy2010-04-21

I will provide both for $12 shipped. Do you want a Rev.1 or Rev.2 catchplate?

author
Airsoft Guy (author)CaptainSlug2010-04-21

 i just suscribed man

author
Airsoft Guy (author)CaptainSlug2010-04-21

 by any chance can you get a good catch spring replacement for a nitefinder i will buy the k26 spring to

author
Airsoft Guy (author)2010-04-18

 do you mean 2 to 3 more plusbows

author
MAVREV13 (author)2010-03-18

i ment ideas on moding it to look like one an ar15 armorlite.

author
MAVREV13 (author)2010-03-15

hey captainslug i need advice on makeing my recon look more liker an ar15 armorlite and im wondering if u could help me out. here it is

008.jpg
author
CaptainSlug (author)MAVREV132010-03-16

No.

author
MAVREV13 (author)CaptainSlug2010-03-16

thanks any way do u know any one that could help with makeing it more like one. oh nice mods i looked u up on youtube nice mods dude you are vary awsome im wondering how do u get your ideas.

also what is the farthest a modded recon can get with out
1 brakeing it at 2 shots or modding it to where people dont believe that it was a recon in the first place (crazy insain super mod)?

author
zack attack (author)2010-03-16

How much $$ did u sell it too uin13? ps: he is awsome.

author
CaptainSlug (author)zack attack2010-03-16

I didn't sell him one. He commissioned one from someone else.
No, he is not awesome.
I don't do range tests with stock darts. With stock darts of any kind you're not going to get the kind of ranges or accuracy you would with homemade darts.

author
zack attack (author)2010-03-16

HOW FAR DOES IT SHOOT WITH NORMAL DARTS!!!       
ps( i didn't capitalize it to yell at u, i just wanted to get ur attention.)

author
MAVREV13 (author)2010-03-13

this is beast does this + = or get more range than a epic ls or nerf crossbow

author
CaptainSlug (author)MAVREV132010-03-13

Heavily modified Longshots typically max out at 90 feet, and won't be terribly durable. They also won't be very consistent beyond 50 feet.
Heavily modified crossbows top out at 100 feet typically. But is most consistent up to 70 feet.
A well made +bow on average will reach up to 120 feet and is quite consistent up to 90 feet.

author
MAVREV13 (author)CaptainSlug2010-03-14

wow that is cool. also how long did makeing the first one take and did u alone make it or did u have help

author
crazyboy007 (author)2010-02-12

 could you use a dremel to make the cuts needed?

great job by the way

author
CaptainSlug (author)crazyboy0072010-02-12

No

author
Jimpiedepimpie (author)2009-11-03

Awesum
But does it fire stock darts(the tagger ones) aswell?

author

It says "Add prefered berrel", so yes.

author
nightwork (author)2009-12-01

Would it be possible to have a copy of the CAD files you used to make the gun? I would like to have the parts CNC made, and that would save me from having to remodel them all. I can work with almost any CAD package. Thanks

author
jam BD (author)2009-11-30

Really well done!!!
It is sooo well made.
Looks good.
AWESOME =D

author
meddler (author)2008-01-07

I don't have the tools to make this, but damn! that sure looks sweet

author
Wasagi (author)meddler2008-08-08

Same

author
MadBricoleur (author)Wasagi2009-08-26

yup. CS's guns (and tools) are the beast lolo