Trebuchet complete

[johnridley]

well, mostly. Everything's built. I need to adjust some stuff, I need to buy some rope and make a sling, I need to buy some more hardware to really secure the weight box. The throwing arm needs to be trimmed and some hardware added.

I had these ridiculous ideas of having some people just pull down on the sling to get the thing ready to fire. WRONG. We dry fired it with no weight in the box, and it took three of us to pull it down, and I was nervous about that. I could hold it down myself without too much trouble, but it's awkward to pull down, and the whole time you're thinking "if someone lets go, this is going to tear up my hands and hurt me."

Luckily I did buy a winch for this project. I will need to find pulleys too. Lowes only has really crappy 200 pound pulleys that I put back on the shelf, I don't trust them. I don't think I'd even trust them with their rated weight.

Ah, I see Harbor Freight has decent-looking double-pulley blocks rated 300 pounds. One more reason for a trip there tomorrow.

Oh well, this wouldn't be a berzerker project if I just showed up with it ready to rock. There'll be plenty of participation with this project.

For your enjoyment...

Comments

[erikvolson.livejournal.com]

Don't drill a hole -- use a strap around the beam. You might need a couple of small screws to keep it from sliding, but that'll cost you much less strength than a through hole for a large eye.

[johnridley.livejournal.com]

What, plumbing strap? I suppose but I don't think it's nearly strong enough. I guess I could get some 1/8" flat steel stock and shape something from that, but I think it's overkill.

[erikvolson.livejournal.com]

I was thinking loading strap, but strapping iron would probably be enough. Heck, a rope hitch is probably enough.

[johnridley.livejournal.com]

Yeah, I got pulleys with fixed eyelets, and I'm thinking just secure that to the pole with rope. I got some pretty decent braided rope from harbor freight (good enough for this, I wouldn't want to go climbing with it...).

To a large extent I plan to show up with the 95% completed unit and a bunch of spare parts and get some collaboration on this.