Hi! I want to change mine to a 12 foot top bar. I saw a post awhile ago that the top bar was made with a very stout plywood long box, does anyone remember that post?
I did a 12’ bar using some microlam beam bits I had laying around. It is quite stout and seems to be working pretty well (aside from some possibly static dust collector related hardware issues)
I added 20" of chain and went with 30" from the chain to the top of the work piece. I also did counterweights instead of a spring or bungee.
Do you remember what your chain length values are? It’s easier I feel if I just find lengths that worked well for other people, I want to copy your top bar design also
for a 10’ top beam you need ~11’ of chain, once you get to 12’ and longer, you
need enough chain to go over both sprockets, so ~top beam length + 6 in, so
I added 18" for 12.5’, as the wise dlang suggested.