basically, with a top beam design (a solid piec of wood between the motors) you
have the stiffness that you need, fastening it to the wall doesn’t change things
The rest of the frame just needs to be stiff enough that it doesn’t let the
material you are cutting warp so much that the sledcan end up riding on high
spots and not cut the low spots in between (which means it doesn’t need to be
especially strong, a piece of plywood wih one 2x4 cross the back of it is
angle and sled have not seen significant experimention recently, and none since
we have chain sag compensation, we need to have soemeone test this again
either of the two triangular kits should work, unfortunantly nobody has had the
time to do any accuracy tests of both linkage kits and the ring kit (we now have
a good way to measure the accuracy)
I repeat my offer that if someone is going to compare the kits, I’ll send them a
top mount kit for free.
As for other improvements, if you are planning to cut thick stuff (over ~1 inch)
you should probably plan to have some way for the top beam to move forward of
the rest of the frame so that the chains can stay parallel to the frame.
See the topic I posted last night on chain takeup for a possible improvement for
dealing with the slack chain.
it uses five 2x4’s (plus some scrap 2x4), a piece of 1/2" conduit as the hinge, and a 10’ piece of unistrut for the top beam. The supports for the conduit hinge are pocket screwed into the wall framing.