And a smahsing time was had by all…

Chucky has succeeded in busting his new arm after a full power test today. He consistently threw 90 meters (295′) until there was a slightly different sounding CRACK, and the ball went straight up, and the top part of the arm went forward.

busted.jpg

What did we learn?

This puppy has some real kick! We’ve also gone out and gotten some green gum that has a bit more spring to it. One of the cross bars was also split, and it’s clear that is was taking more hit than the other, so some changes are being made with a wedged stop plate to be added, to take the arm flat over most of its length when it hits.

More may be reported at Oz’s.

UPDATE: We went out and grabbed some gum thats been loafing and I’ve turned up the first two bits to play with. Being greenish its damned heavy, but also very solid. Lets see what we smash next. My pick would be the crash plate I’m going to add.

throwing-arms.jpg

This entry was posted on March 10, 2007 at 5:32 pm and is filed under Hitting metal with a hammer, Siege engines. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

8 Responses to “And a smahsing time was had by all…”

  1. mojo Says:
    March 10, 2007 at 7:39 pm

    Wood for the throwing arm looked a tad flawed at the outset … it’s a little like these climate models you know, what comes out is an artefact of the integrity of what goes in in the first instance.

  2. Oswald Bastable Says:
    March 10, 2007 at 7:55 pm

    With hindsight, pine wasn’t probably the best choice but:

    It was there

    It was free!

  3. Steven Den Beste Says:
    March 11, 2007 at 1:14 am

    Jeeze, I didn’t expect that! Maybe you should have stuck with the axe handle after all!

  4. george Says:
    March 11, 2007 at 6:41 am

    What you need for flex is a piece of white pine [kahikatea] or a spar of genuine Canadian oregon-not the local douglas fir. Perhaps the cross arms can be damped across the impact zone with a leaf spring to absorb the impact?

  5. Oswald Bastable Says:
    March 11, 2007 at 12:36 pm

    It may not be period-correct, but a few bits of old car tyre under the rop padding?

  6. Old Fat Sailor Says:
    March 11, 2007 at 11:32 pm

    From a bow making perspective try finding a log that can be split to form the arm and then shave the billet to size, the problem with milled lumber is it has no respect for the grain.

  7. Big Haz Says:
    March 12, 2007 at 4:30 pm

    You piece of pine is from the weakest part of the log; the pith. you need to either take a length of timber from the outside of the log or use a different species.

    Cheap sources would be some of the eucalypts that grow in the North Island [assuming that's where you are], even a bit of curly grained blue gum would be better than pine.

  8. Murray Says:
    March 12, 2007 at 4:52 pm

    Thanks for that Haz. We’ve moved on to some of this handy gum being the bargain basement price of free.

    The fun part will be making up a set for the ballista which is due to get under way soon.

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