@Willja67: Good to see the variation on the design. I like the cost-saving methods you employed on the sled. The plywood you used also looks to be pretty nice, which should give you a good, strong sled.
This is a concern of mine as well. I have specified Baltic Birch in the instructions in the hope that the more even ply layers will give more strength. You may also be able to shape out a bit of solid wood to make something more reliable.
If you check out @huntleybill’s sled above, he actually printed plastic clamps for that reason. I know that doesn’t help anyone without a 3D printer, but the alternative is a good one.
The ring currently is the most commonly used triangular kinematics system because it’s @Bar’s idea. I’ve attempted to test which system, whether it’s the ring, 45 degree linkage, or top-mount linkage, but haven’t had the time to finish the test. I tested the two linkage systems against one another but I haven’t procured a ring from Bar yet to test it. When I get more time to work on my machine, I plan on finishing my own tests. So much has changed with my machine both with the hardware and with all the improvements to the firmware that I would need to test each system again (although I’ll be skipping the old quadrilateral this time). That being said, anyone should be able to run the tests if they have the different styles of triangular kinematics.
We go into more detail in this thread:
Depending on the style of linkages, it’s either 1/4" birch plywood in the case of the 45 degree linkage, or 3/16" stainless steel for the top-mount.