WMD, Day 2
Picked up another six 2x4s and continued work on the trebuchet. I had a new/better idea for the trigger mechanism, which has been bothering me. The need to support 60 lbs. of weight and release it cleanly, without jerking the engine around or blocking the arm motion, is a little tricky. It would be a lot easier with a traditional design, but the floating arm bit adds to the challenge.
So, I cut the four long and four short pieces for the weight guides, then the remaining two base frame pieces plus the two cross brace piece. Cut lots of dadoes and pre-drilled some bolt holes and screw holes. Theron showed up in time to help with that.
A lot of people don't understand screws that well. When you want to screw two pieces of wood together, you want to pre-drill the first board so the screw doesn't bite into it. Then, when you tighten the screw, it goes into the second piece and pulls the first piece to the second piece. It's nice and tight. When you just screw through the two boards, the screw doesn't pull, and you get a looser join, or even, if the screw doesn't bite nicely into the second board, end up pushing the boards apart.
Anyway, then we assembled the four base frames and the two wight guide frames. Each is rectangular, with dadoed joints that were fastened with carpenters glue and two screws in each corner. The assembled base frames are 18" wide and 24" tall, while the weight guides are 8" wide and 79 inches tall.
Day two complete.
Next session (in a couple of weeks, when Bernie gets back from a summer roadtrip with the grandkids), I'll add the mounds for the base frame pieces to the base, get all of the bolt holes drilled, test assemble the base devise, and maybe even get the fixed wheel mount built.
So, I cut the four long and four short pieces for the weight guides, then the remaining two base frame pieces plus the two cross brace piece. Cut lots of dadoes and pre-drilled some bolt holes and screw holes. Theron showed up in time to help with that.
A lot of people don't understand screws that well. When you want to screw two pieces of wood together, you want to pre-drill the first board so the screw doesn't bite into it. Then, when you tighten the screw, it goes into the second piece and pulls the first piece to the second piece. It's nice and tight. When you just screw through the two boards, the screw doesn't pull, and you get a looser join, or even, if the screw doesn't bite nicely into the second board, end up pushing the boards apart.
Anyway, then we assembled the four base frames and the two wight guide frames. Each is rectangular, with dadoed joints that were fastened with carpenters glue and two screws in each corner. The assembled base frames are 18" wide and 24" tall, while the weight guides are 8" wide and 79 inches tall.
Day two complete.
Next session (in a couple of weeks, when Bernie gets back from a summer roadtrip with the grandkids), I'll add the mounds for the base frame pieces to the base, get all of the bolt holes drilled, test assemble the base devise, and maybe even get the fixed wheel mount built.