An internal angle of 120 degrees creates a 1:1 on each leg of the chain.
The current design would have a angles greater than 140%.
https://www.ropebook.com/information/vector-forces/
I’ll keep reading. Thanks for sharing all the knowledge and ideas.
Just some thoughts.
-Tim
If you use a unistrut top beam, it would be fairly easy to get some trollies and hang a panel saw frame under it.
yes, but what are you meaning from this?
In this frame there just aren’t that many places you need to do this.
If you are trying to do bolts for the top beam supports, they need to be at as close to a 90 degree angle as possible, and even more importantly, the same on both sides. Bolts 2 inches apart are just not going to be accurate enough (the little amount of error you get in each bolt hole will multiply out the length of the part)
The only other place that needs a bolt is the top of the legs, and that can accept some error.
I edited my first post as you typed this.
I’d like both: unistrut top beam for motor mounts.
Conduit top rail for frame rigidity and carriage rail.
Also added the YouTube vid.
“yes, but what are you meaning from this?”
Edge cutting accuracy.
As the force vectoring increases above 100% does this impact the ability and accuracy of the edge cuts?
Tall top beam, higher motors, smaller angle on the sled attachment, means less force required to drive the sled.
you are worrying about the wrong area, at the outer edges, the chain angle gets up to 80 degress (10 from vertical, so an included angle of 20 degrees), the side force available there is small.
This is why going to a 12’ top beam is expected to improve things noticably, but 10’ is already pretty big, and it looks like we are getting close to ‘good enough’ accuracy now, so the ‘stock’ design will probably remain at 10’ wide
I’ve started a wiki page so that we can tweak the assembly guide without huge walls of text here
slight tweak in the ordering, step 1 is attach lower blocks (opposite side of the kickers), same process as the kickers, but without the need to raise things from the ground
The wiki page I’m working on is https://github.com/MaslowCNC/Mechanics/wiki/Feb-2018-Frame
I’m late to the party here. Robotics season is upon us, so even though our Maslow kit has arrived, assembly of it will have to wait until we get our robot built. But before build season started, we did finish our frame with panel saw. So I’m gonna use this thread to show it off. It’s my “alternate frame design” which I posted quite some time ago. The panel saw sled was cobbled together with whatever hardware was around, so it’s not the most refined design, but it’s solid. The counterweights aren’t installed in the picture.
That looks like it works well with the Unistrut. Are those rollers at the top? Do you get any sag from the weight?
Think I’m going to add that to the ToDo list 
Building robots means you have lots of bearings to work with. We happened to have some that were just slightly smaller in diameter that the interior width of the unistrut. The round things you see at the top are just fender washers to keep the counterweight cables from slipping off their bushings. I haven’t noticed any sag even with the weighty sled.
unistrut has roller trucks that are designed to hang from the strut and roll, so if you put the slot on the bottom, you can use those (just find a way for your track saw to not interfere with the slack chain)
thinking about the panel saw, it doesn’t need to have rollers, something that just hooks over the top beam would work. I’ll do up a CAD of it after I finish doing the assembly step diagrams
going through all the details in making the step-by-step ssembly instructions, I ran across one issue.
With 5’ rear legs, you have to clip the top front corner of the legs or they will hit a full sheet of plywood.
To avoid this, we would either need to
I think it’s reasonable to clip the corner (and then I don’t need to tweak 16 different cad models )
Thoughts?
Don’t drop the plywood. The current height is already challenging enough.
Just a thought when you are figuring out a list of what a somebody would need for lengths of 2x4’s if you double the length the price is over double.
Here is a list from Menards.
8’ $2.98, 10’ $3.95, 12’ $4.98, 14’ $5.29, and 16’ $6.89.
If you could get stud length.
92 5/8 $2.75, 104 5/8 $3.19, and 116 5/8 $4.49.
There is also the problem of not everybody having a vehicle that can handle long loard lengths.
We need to get a 10’ long board for the top beam, so it doesn’t make much sense to try and use ones smaller than that.
There are advantages to going to a 12’ top beam (although that needs an extra foot of chain on each side)
I discovered that onshape has an option to export all sheets in one file in dxf/dwg please check if you can use these
Maslow Assembly Steps.dxf (91.4 KB)
I’ve got to run, so I can’t convert these pdfs to .svgs until later
I can’t figure out how to add images to the wiki
https://github.com/MaslowCNC/Mechanics/wiki/Feb-2018-Frame
step 1.pdf (488.8 KB)
step 2.pdf (468.8 KB)
step 3.pdf (494.0 KB)
step 4.pdf (468.8 KB)
step 5a.pdf (504.4 KB)
step 5b.pdf (479.7 KB)
step 6.pdf (475.0 KB)
step 7.pdf (477.4 KB)
step 8.pdf (481.2 KB)
step 9.pdf (482.9 KB)
step 10.pdf (489.8 KB)
step 11.pdf (476.0 KB)
step 12.pdf (483.2 KB)
step 13.pdf (485.3 KB)
step 15.pdf (496.3 KB)
step 16.pdf (503.6 KB)
step 17 (complete).pdf (430.4 KB)
Tried importing into visio and only got one sheet (and by size of file, likely just one sheet was exported) Title block was messed up and everything was line segments, so trying to color wouldn’t work. Still thinking on how best to do it… You can’t put fasteners into onshape, correct?
