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Zheng3 Penny Ballista

by zheng3, published

Zheng3 Penny Ballista by zheng3 May 22, 2012

Description

This nefarious device can easily launch a U.S. penny across a room when printed at 1:1 scale.

It's the first upgrade many Seej players seek when they need a little more oomph than the Zheng3 Penny Catapult can provide.

Seej is an open-source tabletop wargame based around 3D printing.

s33j.net

Do you need this in your arsenal? Yes. Yes you do.

Penny not included!

Now available on Shapeways for folks without access to 3D printers! bit.ly/N9iw2C

Recent Comments

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Thanks for this ballista I just printed it. Tommorow I will get the rubber bands and we´ll see if it works

I printed the ballista and it looks great. The problem I am having now is that I cannot figure out how to attach the rubber bands. I have them both connected to the half-round pieces but I can't figure out how to connect the two rubber bands without offsetting the penny holder. It says to center the holder on the knot but that doesn't seem to work out. Am I really supposed to tie the two rubber bands together? Wouldn't some type of hook have worked?

Can you upload just the parts as files? When I printed, only the crossbow came out correctly.

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License

Zheng3 Penny Ballista by zheng3 is licensed under the Creative Commons - Attribution license.

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag. Print Thing Tag

Instructions

zheng3.com/?p=361

Construction is really simple! Needlenose pliers are recommended, but not strictly necessary.

You'll need two elastic bands to complete this ballista. Tie a single band through the bore on one of the two D-shaped locking keys. Repeat the process with the other locking key.

Feed the end of one band through the rectangular bore on the ballista's left post. Insert the tenons of the locking key into the square mortises on the post to lock the band in place. You'll be tempted to repeat the process with the other side, but don't give in. It will save you precious minutes of frustration.

Unlike the Zheng3 Penny Catapult, these locking keys should be a snug fit. If some settling of the plastic during printing has made the mortises too small, trim the tenons a bit with your blade of choice.

Center the nock on the knot that connects the two rubber bands. Make sure that the penny's cradle is facing forward.

Feed the end of the band that's been locked down through the rectangular bore on the nock. Tie the free end of the band to the second band. Now feed the free end of the second band through the outside of the rectangular bore on the right post and loop it through the second locking key.

The nock has a wee nub on its underside. Slide this nub into the ballista's firing groove; it will improve accuracy.

Load a penny into the nock, pull it back, and fire away. Be safe!

Seej is a tabletop wargame based around 3D printing. Check out s33j.net for rules and more information.

Or just jump right in and download the Seej Starter Set: thingiverse.com/thing:24013

You can also search Thingiverse for Things with the seej tag.

Be sure to check Zheng3.com for updates. If twitter's more your thing than follow Zheng3 at twitter.com/Zheng3_Jim

Flagrant stagecraft alert: There's a piece of hookup wire holding the nock in firing position for dramatic flair.

Thing-O-Matic users may want to check out the Zheng3 Short Stock Penny Ballista, which will fit on a 120x120mm build platform: thingiverse.com/thing:23545/

EDIT 6/1/12: There's a new STL that fixes some flipped normals and weird N-gons on the locking keys. If you're having problems printing the previous version, try the clean model. ReplicatorG is pretty forgiving, but other slicing software may be less so. Good luck. We're all counting on you.

Comments

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brotherhood on Apr 3, 2014 said:

Thanks for this ballista I just printed it. Tommorow I will get the rubber bands and we´ll see if it works

Scoobytoth on Jan 13, 2014 said:

I printed the ballista and it looks great. The problem I am having now is that I cannot figure out how to attach the rubber bands. I have them both connected to the half-round pieces but I can't figure out how to connect the two rubber bands without offsetting the penny holder. It says to center the holder on the knot but that doesn't seem to work out. Am I really supposed to tie the two rubber bands together? Wouldn't some type of hook have worked?

yorker78 on Sep 25, 2013 said:

Can you upload just the parts as files? When I printed, only the crossbow came out correctly.

Joe_Murphy on Jun 20, 2012 said:

YES!

Daid on Jun 20, 2012 said:

Looks like you designed this for US elastic bands. NL bands are larger and almost impossible to fit in. FYI, NL bands are 8mm wide and 1mm thick. (might be the same for the whole of europe, don't know that)

It is possible to get these bands in, but I damaged the band during insertion. So I hope it will hold up during use.

cymon on Jun 18, 2012 said:

Has anyone tried printing the pennies to shoot with this?

k1nc41d on Jun 1, 2012 said:

Had a problem printing, the carriage for the penny broke free from the pad. Can you post the file as individual pieces?

zheng3 on Jun 1, 2012 said:
ZaphodBeeblebrox on Jun 1, 2012 said:

For this Seej game, are rubber-band powered, penny-tipped battering rams allowed?

zheng3 on Jun 1, 2012 said:

Yes! See Core Rule #2 at http://www.s33j.net

As long as your opponent agrees to play against you with whatever strange device you bring to the table, it's legal.

CiaranMcG on May 23, 2012 said:

When i was creating the gcode for this with slic3r, it came up with the error "This model has overlapping or self-intersecting facets" and "the input file was not marnifold near edge 122.000000-121.000000." When i printed it then it started printing from the layer above the front arch of the ballista. Any idea why this is happening? I printed the catapult the other day and its fun as hell, so i'm dying to get this one printed! Thanks!

zheng3 on May 24, 2012 said:

EDIT! There's now a model that works with slic3r! There was some nonmanifold geometry around the bow that made slic3r choke but ReplicatorG let through.

I left the original version in place because if it ain't broke, don't fix it. Slic3r users should download zheng3_penny_ballista_slic3r.stl.

zheng3 on May 23, 2012 said:

I'll look into it. I've been using ReplicatorG to generate my gCode... maybe's it's a little less touchy than slic3r for this model.

MacGyver on May 23, 2012 said:

I really wanted to print this but it is just barely too large to print without scaling on my 120mm x 120mm Thing-O-Matic heated build platform.

zheng3 on May 23, 2012 said:

Here you go:

http://www.thingiverse.com/thi...

Let us know how it turns out!

thantik on May 22, 2012 said:

Thingiverse needs more office-weapons. :)

zheng3 on May 22, 2012 said:

I'm workin' as fast as I can, cap'n!

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