Trebuchet Kits, OpenBeam in precut lengths, closing out the Kickstarter campaign

We're back home from World Maker Faire, New York. What a trip! Thanks everyone who came by to the OpenBeam booth. Some good things will be coming out of this, I'll update everyone when the deals are finalized. :-) As with every major Maker Faire, I managed to go home with Con Crud (™). I guess that's what you get for burning the candle from both ends and hitting the middle with a flame thrower.Here's an update to our Kickstarter status:

1) There are still about 20 or so kits at Metrix. I have borrowed the tape robot back from Dan Terry, and I'll be repacking these kits for Fedex shipping this coming weekend. (All Seattle area kits were packed before the ship tests and before the subsequent discovery that the package will not hold up in Fedex transit. Once the kits have been repacked, it should be a 2 day affair to get them shipped to our Seattle backers. So, if you're in the Seattle area and have not picked up your kits, they will be shipped to you next week.

2) The limited edition prints will hopefully go out towards the end of next week. I've signed about 1/3 of them - still about 300 pages of engineering drawings to go through. :-P. Maybe I should make a point to sign 5 sets per night so I don't end up with carpal tunnel…

3) Finally, the trebuchet kits. These 12 kits had been a long time in the making…

When I first started on the trebuchet kits, I wanted to do them properly - by putting in place an infrastructure so I can offer precut pieces to my customers. One of the biggest challenges of OpenBeam in its early days is that not everyone has a chop saw. That became very obvious when pieces of OpenBeam started showing up at my home hackerspace looking like they've been chewed on by a rabid dog. (No offense, Matt!)

Cutting the extrusions myself on a chop saw just wasn't an option. To be honest, neither is paying for someone else to cut this on a chop saw - it's just too expensive. Repetitive tasks like this really should be done by a robot. Fortunately, the fine folks at TwinTec-MicroRAX already has a robotic chop saw that they've built for MicroRAX. So we worked out a deal and I helped them with some modifications and programming on their AutoSaw.

Here's their AutoSaw:


It's basically a pneumatic actuated saw with a CNC stepper motor controlled shuttle that ferries the OpenBeam into the saw. Here's the saw carriage:


My addition is the feather board you see in this shot. It helps to keep all the extrusions against the rear fence so that all the cuts are at 90 degrees to the beam:


The folks at MicroRAX modified the guard to allow the 15mm OpenBeam to pass through. This is actually a fairly dangerous modification; before, at 10mm it wasn't wide enough to slide fingers in. Now that it's opened up to 15mm, fingers can now be slid in, only to be clamped in place by the pneumatic powered jaws and saw through with the blade. For obvious reasons, I use the (sacrificial) shuttle to push any OpenBeam out of the saw….


Here's the cut extrusions coming out of the saw. They fall into a collecting bin after they've been cut; we actually set aside different bins to hold the output from the saw. Here's one that you may be familiar with:


Here's a quick video clip showing the saw in action:


Pretty nifty, huh? With this new MicroRAX partnership, we opened up a few opportunities:

First of all, we are happy to announce that Metrix:Create Space will now be stocking precut OpenBeam. This is an awesome addition to their collection of OpenBeam inventory; if you're in Seattle, that is really where you'd want to be to work on OpenBeam projects.


Secondly, we've been working on a precut kit. We are still fine tuning the packaging, kit contents, etc, but it will be listed on the OpenBeam webstore sometime this weekend. Response to the kit had been very positive at the New York MakerFaire as well.



(Precut extrusions shown with prototype laser cut cardboard packing "sled". Eventually the cardboard will be die cut / punched, but using a laser to prototype allows us to get to the market quicker.

With this foundation laid, we've re-engineered the trebuchet kit to use only standard length components. We then come to the realization that we somewhat overcharged people for the trebuchet kits. So, as an apology for the kits being late, we are upgrading everyone who bought a trebuchet kit to a precut OpenBeam kit, and then throwing in the extra extrusions / bearings / brackets / laser cut parts to complete the trebuchet.

Here's a few pictures of our older prototype:


The hook gave us the most grief: For this to be a true trebuchet, we implemented a break-away, re-usable sling that increases the lever arm of the machine during a toss. Getting the sling to release properly and reliably was a challenge, to say the least. So, kudos to the medieval engineers before us who figured this out.


Here's the weight box. It's filled with M3 nuts. :-)


And here's the prototype sling held in ready-to-fire position.

We still have to validate the latest laser cut parts, give the laser cutting order to Metrix, and print the engineering prints that the trebuchet kits have to ship with. We now expect these kits to go out on or around Oct 22nd and that will mark the end of our kickstarter campaign (when all our backer rewards have been fulfilled.)

Thanks for reading,

-=- Terence, Rachel and the furry monster puppy