bought your plans and have begun planning out the construction. They are excellent by the way."
Q. Based on your design what is the weight limit of the projectile? How heavy and what do you have your counterbalance made of?
The design weight of the projectile is 3 to 5 lbs. The counterweight is 400 lbs. The counterweight material is earth (we used bags of top soil)
Q. I am looking for something that we can transport in the bed of our pickup (with a shell) and then assemble at the site in fairly short order. Do you think we can modify your plans to achieve this goal?
One of our trebuchet customers came up wwith an interesting approach to this problem. Click here to read his comment "Modified Treb fits in Van".
Q. Where did you get the axle for your treb? Thanks!
I found the axle at a steel 'scrap and recycle' yard in our town by doing an internet search. Some of the keywords I used to search are:
metal salvage yard, sarasota
metal scrap, sarasota
metal recycling, sarasota
Hint: Use the name of the town or area where you live if you want to filter out the big national companies. As you can see, I used Sarasota for my search to do this.
Q. What size line do you use for the sling?
We use 5/16" braided line.
Q. How long is the sling pin? How long is yours in total length and how much sticks "out". It looks like you have a metal ring that goes over this, how do you keep the ring from sliding off the pin when the machine is in firing position.
The sling pin is a piece of 1/2" steel pipe, it fits into a larger piece of pipe we lashed top the throwing arm. Pin is held in place with a screw into the throwing arm. It extends out around 6-8".
Q. How do you keep the ring from sliding off the sling pin when the machine is in firing position?
The weight of the projectile keeps the lines taught before you fire the treb. Lead the sling back and load it with your projectile. The ring wont slide off until the arm is going upwards.