That is full sized 4’x8’. When working on it, I change the parameters a lot to make sure nothing breaks, so depending on what save you are looking at it could be 2’ to 20’ in either direction.
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Isnt the point of parameteic to be that it can also be full sheet capable?
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Any thickness material works. I recommend MDF but Aluminum works just fine in that file.
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Sorry for mistaking it for being small! I will edit the above comment about it!
At some point in myu life I may just let someone else to the design work and just take something as designed… that point hasn’t come yet. I’m liable to at least tweak something or do my own add-on.
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Huge thanks to Ryan, not only for all his design genius that I parroted for this, but also for releasing his table design. I worked to finish two Fusion 360 files (parametric, editable) for both a wood side rails version and a metal strut side rails version. I also completed DXF files, and two ready-to-cut, pre-arranged DXF cut plans (for a common thickness of 4’x8’ sheet goods, 23/32"). See below for details and links.
Views, info, and downloads for parametric CNC Table with Wood Side Rails and option with Metal Strut Side Rails:
Table with Wood Side Rails
Table with Metal Strut Side Rails (aka Unistrut, aka Superstrut)
As of April 13, 2023, I have completed Fusion 360 editable parametric files for both a CNC table with wood side rails and a CNC table with metal strut side rails. Also, I have completed ready-to-cut, pre-arranged DXF cut plans (in inches, not metric) for both the wood side rails version and the metal strut side rails version.
IMPORTANT: This is all based on a common sheet good thickness of 23/32″ for the torsion box, and that can be cut from a single sheet of 4’x8′ plywood / MDF.
Please measure your plywood / MDF, and if it is different from 0.719” (18.2562 mm) thickness, then you will need to download the Fusion 360 file, edit the user parameters, and change the value of the parameter named Slot_Width. Then in each component, right-click on the sketch identified as “for DXF” in the name, and choose “Save as DXF” to export it. The only two components affected by this are the “X Ribs” and “Main Y Spars” (which together make the main body of the torsion box).
For the metal rails version, only one 4’x8′ sheet is needed for the torsion box, with off-cut strips from the MDF “bottom skin” serving as side rail supports for the metal struts.
NOTE: for the metal strut rails version, you can download and use my printable table extenders that insert into metal struts to provide endstop/tensioner support. The link is: https://www.printables.com/model/220187-lowrider-3-cnc-table-extenders-to-use-lr2-table-wi
For the wood rails version, the cut plan also includes a second sheet (of which only half is needed, so the unused part can be saved for some other project) which handles all the “long” items for the “riding plates” and the side supports for them. Any reasonable thickness of any 4’x8′ sheet good can be used for these cuts. These are set up for cutting each long part as 3 pieces that can then be glued together.
As of this current set, other thicknesses of plywood / MDF can be handled by either downloading and editing the Fusion 360 file (edit the user parameters and change the value of the third parameter, named Thickness_Plywood_Material) or make a request to me to edit and generate a new cut plan.
Note: My design plan calls for a 1/2″ thick MDF “top skin” on the torsion box, which is considered “permanent,” and then a sacrificial 1/2″ thick MDF spoil board on top of that. If you only re-surface the sacrifice layer, then the torsion box itself only has to endure maybe screw holes from attaching things, and should not need much attention when time comes to replace the spoil board. If this plan is not your cup of tea, you can edit the X Rib sketch and the resulting solid body to change the wing heights as needed.
Inspired by Ryan’s 3D “napkin sketch” illustration of a CNC-cut table for LR3…
Benefits
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- Affordable, requiring only one (1) 4’x8′ sheet of 3/4″ plywood / MDF for the torsion box, and for the “riding plates” (also referred to as “side rails”) either a second 4’x8′ sheet, 1/2" thick (of either MDF / OSB / particle board / plywood), or two (2) 10′ metal struts (aka “superstrut,” aka “unistrut”). As of April 2023, my material cost locally for the 3/4" plywood + 2 unistruts approach is $140 (not including the 1/2" MDF sheets for bottom skin, top skin, and sacrificial spoil board layer, or screws, bolts, etc).
- Incredibly strong torsion box design, helps make the task of getting a decently flat table more within reach.
- Can be “bootstrapped” for new LowRider v3 makers who don’t yet have a table, through making a temporary cut surface by laying a spoil board “stack” on the flattest floor you have available, flanked by some boards for the LR3 to ride on, clamped to the spoil board stack.
- CNC cutting of the X ribs and Y spars helps ensure proper dimensions, ease of assembly, greater stability, and best shot at flatness.
- Compatible with my mod to protect/hide one of the long side belts. If you choose the option for metal strut side rails, my mod is ready to implement. If you choose the wooden side rails option, some remixing would be required.
Online Preview Links
Editable F360 archive file downloads…
for LR3 TABLE WITH WOOD SIDE RAILS:
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- Wood Side Rails, 21/32’’ plywood (Slot_Width 0.65625’’ or 16.66875mm) 3 5/8’’ tall
- Wood Side Rails, 23/32’’ plywood (Slot_Width 0.719’’ or 18.2562mm) 3 5/8’’ tall
- Wood Side Rails, ~.75’’ plywood (specifically Slot_Width 19.15mm, or 0.75393701’‘) 3 5/8’’ tall
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for LR3 TABLE WITH METAL STRUT SIDE RAILS:
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- Metal Strut Side Rails, 21/32’’ plywood (Slot_Width 0.65625’’ or 16.66875mm) 3 5/8’’ tall
- Metal Strut Rails, 23/32’’ plywood (Slot_Width 0.719’’ or 18.2562mm) 3 5/8’’ tall
- Metal Strut Rails, ~.75’’ plywood (specifically Slot_Width 19.15mm, or 0.75393701’‘) 3 5/8’’ tall
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DXF cut plans
for TABLE WITH WOOD SIDE RAILS:
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- Wood Side Rails, 21/32’’ plywood (Slot_Width 0.65625’’ or 16.66875mm) 3 5/8’’ tall
- Wood Side Rails, 23:32” plywood (Slot_Width 0.719” or 18.2562mm) CUT PLAN
- Wood Side Rails, ~.75’’ plywood (specifically Slot_Width 19.15mm, or 0.75393701’‘) 3 5/8’’ tall
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DXFs for TABLE WITH METAL STRUT SIDE RAILS:
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- Metal Strut Side Rails, 21/32’’ plywood (Slot_Width 0.65625’’ or 16.66875mm) 3 5/8’’ tall
- Metal Strut Rails, 23/32’’ plywood (Slot_Width 0.719’’ or 18.2562mm) 3 5/8’’ tall
- Metal Strut Rails, ~.75’’ plywood (specifically Slot_Width 19.15mm, or 0.75393701’‘) 3 5/8’’ tall
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Nice work. I think I will add a new tag for tables to make this a bit easier to find in the future.
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I like your thinking here. However the current designs leverage the strength and rigidity of the torsion box to create a straight, dependable place for the riding plates.
You are kind! Thank you for all your amazing work and generous sharing of your design genius!
Pouring it on thick, just a dude in his garage that likes to build stuff.
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My admiration is genuine. As soon as I saw the new way you were doing the riding plates and supports I immediately saw that it allows various thicknesses to be used and quickly switched my files to emulate that. I can recognize it but I am not yet to a place of thinking to do it without seeing it first! Clever!!
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@jtcweb made some suggestions to me for bootstrapping a way to cut this on the floor. He can chime in here.
One way he suggested is to have the three full sheets of 1/2” MDF (which are planned to be bottom skin, top skin, and spoil board) and lay two side by side making an 8’ x 8’ square, put the third sheet on top in middle, screw it down, and lay some long strips beside the one MDF on top for riding plates. Screw them to the bottom MDF sheets. Attach Y rail and belt tensioners. Boom. Cut your torsion box!
(For the riding plates- could cut shorter strips and screw them in an arrangement to form longer strips.)
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Or t caps
Or 90 degree printed brackets
Or cut the rib layout into the first board 1/3 and totally ditch the front to back boards.
On my scab plan that’s what I am going to try.
The domino or racking or whatever you call it would be gone. Basically a semi monocoque structure.
Wood on floor like you said cut the 1/3 DOC grooves with the rib woods thickness.
Cut your ribs
Glue rib joint into slot channel. Then you have full pass through storage space and lots of strength and no fasteners.
The glue joint on a 3/4” width x1/4” doc.
Would be pretty strong along the whole span and should spread the stress out nice and even. Imo
Haha
Brain seed
On the project page on my website, where I have made download links available, I have now added more resources and information, a clickable table of contents, and a new Q&A section, in which I address the question of whether one can start with the Wood Side Rails version and yet later switch to use of metal struts for side rails.
Bottom line on that question: It’s technically doable, but I don’t recommend it.
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I’m going to read it right now, seems like a lot of good information!
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I also just added (to the notes on my website) this note which is important for any makers who are new to CNC, and wanting to make this torsion box table! Thought I would add it here as well!
IMPORTANT: When setting up your cut job (regardless of whether in ESTLcam or some other CAM software) it is crucial to use the “Overcut” feature on all inside corners that will have another piece of wood fitting into the opening. This feature is also called “dog bones” because of how the result looks. If you don’t do this, your torsion box WILL NOT fit together without a lot of work chiseling and sanding! Below is a screen shot that not only shows me using this feature in ESTLcam, but also showing my tool settings for a 1/4″ end mill cutting plywood, including speeds, feeds, and RPMs. For reference, 17,000 RPM on a Makita 700 series router is done by setting the dial on “3.” If you are using a 1/8″ end mill, the RPMs should be about 24,000 RPM, which on a Makita 700 series router is done by setting the dial on about “4.5.”
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Another important note: When assembling, pay close attention to the orientation of the X-ribs, because on both the design by Ryan and the designs by me, the X-min side is different from the X-max side. Make sure the ribs are turned the right way, so all the X-min sides are together, and all the X-max sides are together. You may want to mark them or label them after cutting and before moving them, so you can easily tell which side is which.
I have just used the one of these designs that is for metal strut to CNC cut (with my LowRider 3) the torsion box out of 3/4” plywood (23/32”). I used glue while assembling the cross lap joints to build the torsion box. I had some OSB that could go on the bottom, and two pieces of MDF that could go on the top, one as a top skin, and the other, as a spoil board. I have assembled the OSB onto the bottom, but I ran out of screws. As soon as I can get some more screws, I will finish attaching the bottom, and flip it over and attach the top skin and spoil board. I took video, but I have not edited or posted it yet.
Got more screws (Home Depot had a sale — got 5 pounds of “yellow zinc plated” all-purpose screws for $7 — can’t beat it).
Got the bottom skin completely attached (screws attaching it to not only the X-ribs but also the Y-spars), and the same on top for the MDF top skin. Also attached the MDF spoil board.
I used off-cuts from the OSB bottom skin to serve as backer boards for the metal struts. Glued the OSB backer board onto the X-Ribs, and used screws to hold them in place overnight, and now I’m removing the screws (so they won’t be in the way for the larger screws that will hold on the metal strut. I plan on pre-drilling for the larger screws in such a way that they bite into not only the backer board but also the tips of the X-ribs. I’m currently attaching the first of the metal struts.