In my research of CNC designs I came accross the mindsparx design before I found and chose LR4.
One thing I rememered from his build is the fact that the torsion box was made in 2 pieces and screwed together, re-watching it just now I also noticed how he didnt glue the top and bottom sheets down.
I have a problem, my workspace is up a flight of narrow stairs and at the top there is an immediate right turn. I can just about get a sheet of 8x4 up and around the corner but dont think I would get a thicker and larger LR4 (for 8x4 ) base out of the workspace when it comes time to move.
For those who have built a torsion bed or a LR before, can I ask how do you think this design would perform? i.e
2 box pieces roughly 1200x1200 each that screw together
Side rails that unscrew
Top and bottom sheets are removable
If required I could add bracing on the sides to strengthen it but since most of the strength is gained from the top and bottom surfaces, I don’t know how much use this would be.
I love Zach’s parametric torsion box design Zach’s Torsion box, I would look to modify the DXF files it produces for my build.
That should be fine. I would use big bolts (5/16" or larger) to attach the two sides and a lot of screws on the top/bottom. Alternatively, you could glue the top and bottom on and if you ever needed to remove it, you could cut those sheets.
Torsion boxes use the tension in the top/bottom to stay rigid. So it is important they have very strong grip on the frame.
Yes I considered smaller, but unfortunately, I regularly need to cut 8x4 sheets.
The worst case scenario is that I would have to destroy the torsion base and rebuild a new one from scratch in the new location.
Just a thought, as the slot together ribs are mainly in compression and as far as I know function only to keep the top and bottom surfaces seperated would a glueless and screw/bolt only verstion work?
PS. Many thanks Zack for the great design youve shared
I built this torsion box table at 5’ X 9.5’. I didn’t glue the top and bottom sheets. They were screwed pre drilled and countersunk into both sides of the of the joints. Seems to be pretty stiff. It would be interesting to see another right beside it that was glued. I don’t have legs on mine as I set it up to be hoisted to the ceiling. It just sets on two sawhorses and I have moved them closer to the center so there is a lot of overhang on both ends just for a test and didn’t notice any deflection. The torsion box with spoil board and LR4 is almost 300 pounds. Maybe this can give you some ideas.
Dan, you are a star! The photos and your message are great verification that what I am hoping to do could be possible. Your LR4 is a whopper!
I am pushed for space and never thought of using a hoist to the ceiling. I will measure up. I had been thinking of building a lid for it so I could both use it as a work bench when not cutting with it and protection.
My parts are almost all printed and everything else has arrived… the build is about to begin (
Dan, did you cut your 9.5’ spars from a 10’ sheet, or did you join shorter pieces?
Also I am in the UK and we dont use Dado blades much, if your struts are interlinking/overlapping slot type, how did you cut them? I have an old dewalt site table saw and a mitre saw with ond stops. The sliding mitre has a depth stop and I am thinking of cutting the slots with the saw but I am not sure how accurate/tight a fit I can acheive…
Not sure if it is available where you live but I used MDF trim for my X & Y stringers. That trim is roughly 3/4” X 3-1/2” and it is available in 12’ lengths. The other trim that the LR4 rides on is roughly 3/4” X 5-1/2”. I used a dado blade to cut the notches in the stringers. The notches that I cut in the stringers slipped together as I did not want to fight them while putting them together. The top and bottom skins are 1/2” MDF as well as 1/2” MDF spoil board. I think if I wanted the table lighter I would use 1/4” MDF for the top and bottom skins but I would glue and screw them. I would recommend leaving enough tolerance so you can slip the stringers together. If you have to force them together it can spread the notches in the stringers and cause them to bow. Just my two cents!
