Torsion LR4 table generator

LowRider CNC Advice
162

I would love to use your generator for a torsion box build, but I don’t get why the y spars is bigger than the rail max length dimension. :thinking:

I’m planning on making a table with cutting surface of 1300x2440mm. The sheet size I’m able to buy is 1220x2440mm, so how would I get y spars, which seems to be bigger than 2440mm?

163

Hi,

The y-spars should be just about equal to your Y-length. There are y-runners (rails, I think they are called in the source) which the side cars run on and which should be split into two pieces, designed to fit into your sheet size.

164

I’m just wondering why the Y beams are automatically split into two by the “Rail max length”, and the Y spars aren’t. :blush:

Thank you for your time!:blush:

165

I’m confused. Your Y spars should be 2440, which is your Y dimension of sheet. It’ll be tight (ends might be a bit short) but it should fit?

166

@franklyrosalind

Thanks for the great tool!

I’ve made an improvement in the below pull-request. It’s got added dogbones with bit-size setting and a fix for the sizing of the exported SVG:

I’m going to make a table soon!

Scherm­afbeelding 2026-07-03 om 22.13.12
Scherm­afbeelding 2026-07-03 om 22.13.121018×602 2.84 KB

167

You guys are way ahead of me. I just started printing my parts.

I have not yet settle on the table size. I am aiming for 1220 x 1220 mm (48x48 in) cut area.

I generated the table and here is what I got:

Screenshot 2026-07-21 231346
Screenshot 2026-07-21 231346958×968 64.6 KB

I must be doing something wrong- or am I missing something?

MillMerge : 1240 x 1240 project.

thanks

168

let me know if you figure it out.

169

Seems there was a mix-up somewhere regarding the units. Mm/inch, mm/cm, something like that.

170

I fixed this in my pull request.

You can run my version on your own computer if you know how to use nodejs with npm.

171

No!

I will do some research!

:thinking: :sad_but_relieved_face:

172

You could try processing the SVG in a LLM like Claude or ChatGPT. Ask it to convert 1px to 1mm. I believe that will also work.

173

:waving_hand:

Mr. Claude did it!

174

Hi there, just a quick question: is it meant to be different? If it won’t be pushed till the end, it will have a gap in between, otherwise, it will stick out.

image
image2632×976 298 KB

175

@ledniy – it’s meant to be a bit deeper than needed. You will have skins attached to the top and bottom which should help keep everything flush. Since this is meant to be buildable without a perfectly-dialed-in machine, it’s much easier to overcut than undercut here.

176

So started to build the torsion box!

I was missing a couple of features in the generator, so i’ve added features to Zach’s table generator:

I’ve changed the size to be exactly right, so any changes in slot-sizes is made in CAM.

IMG_6633
IMG_66331920×2560 905 KB

IMG_6635
IMG_66351920×2560 810 KB

Edit: right quote :grimacing:

177

How long did it take to cut the table?

178

Around 3:30h total for 2 multiplex sheets (easily done in one day with removing tabs and sanding).

Material and size:

  • 18mm multiplex pine (underlayment)
  • Full sheet size 2440x1220mm
  • 70mm rib height for table

CAM Settings

  • 6mm single flute endmill
  • 5mm dept per pass
  • 6 tabs per part
  • 2000 mm/min speed
  • 16.000rpm on DeWalt D26200 (setting 1)
  • Conventional milling

The pine multiplex was bend badly, that made it hard to perfectly align everything… will be much easier with MDF i think… or better multiplex. :sweat_smile:

The top sheet is a 22mm Okoume sheet (2500x1220) we had lying around from a previous project.

IMG_6650
IMG_66501920×1585 606 KB