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Step 7Throwing Arm Assembly
The arm is easy. The lower arms overlap the upper arms by about an inch and a quarter. You just need to line it up and glue it together. Then you need to drill out the axel holes. The axels will be about an inch and a half apart. It's important that you try to get them straight up and down as much as possible. If you have access to a drill press, I recommend you take advantage of it. You should have a little more than six inches of arm above the main axel depending on how close to the end of the lower arm that you drilled the holes for the lower axel.
The main axels are made from 3/16" steel rod. You could use aluminum if you'd like. It'll be easier to cut but usually costs more. I suppose you could even use a wooden dowel but you'll get a bit more friction. Check the distance between your uprights and cut an appropriate length of rod to serve as your primary axel. Tap it through the hole in your throwing arm. Cut another short piece to go between the lower arms to support your counterweight.
Then it's time to add the release pin. This is the business end of the trebuchet and it's important to mount the pin securely. I used a little length of wire from a jumbo paper clip as my pin. The 1/16" hole I originally drilled to accomodate my pin proved too large. Forcing a bit from a smaller paper clip into the hole along with it made for a nice tight fit. You may even get away with chucking a bit of wire right into your drill and trying to drive it directly into the end of the arm.
The main axels are made from 3/16" steel rod. You could use aluminum if you'd like. It'll be easier to cut but usually costs more. I suppose you could even use a wooden dowel but you'll get a bit more friction. Check the distance between your uprights and cut an appropriate length of rod to serve as your primary axel. Tap it through the hole in your throwing arm. Cut another short piece to go between the lower arms to support your counterweight.
Then it's time to add the release pin. This is the business end of the trebuchet and it's important to mount the pin securely. I used a little length of wire from a jumbo paper clip as my pin. The 1/16" hole I originally drilled to accomodate my pin proved too large. Forcing a bit from a smaller paper clip into the hole along with it made for a nice tight fit. You may even get away with chucking a bit of wire right into your drill and trying to drive it directly into the end of the arm.
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Sep 23, 2009. 8:49 AMFallenAngels
says:
what's the width of that metal rod?
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