whomisi
Member
No going back now! I built 8 very tall adjustable frame stands, made lots of measurements and scribe marks along the chassis rails and sent it with a zip disc. Intimidating stuff.
Now I'm getting the extension segments made, as well as the internal stiffeners, then stitch this machine back together. The bend radius needs matching, which affects the flange lengths... trial and error to get the profile dialled in.
Lots of stringlines and straight edges will be required to ensure this all lines up just right. I couldn't find much detail online about this process so I'll document it fairly heavily in the hopes it helps someone else foolish enough to do this.
In Canada at least, finding identical material to the frame has proven impossible, so I went down the rabbit hole of learning about High Strength Low Alloy steels, grades and composition. For my chassis I've landed on the Canadian spec "350W" in 1/4 inch. It seems interchangeable with A572 Grade 50. They are a little higher in carbon content than the original material, and 10% lower in yield strength. However, I've seen test reports showing that the actual measured strength exceeds the minimum. Also, 1/4" is 6.35mm whereas my chassis is 6.0mm, but I'm calling it close enough. My second feasible option was a grade 80 material, far exceeding the strength of the stock material, which gave rise to concern about welding compatibility and failure of the weld. So I've decided a little less is better than a lot lot more. On top of all this will be the stiffening double skin frame overlapping bits.
And it's a bit overdue but the CAD model has finally been started, including a pretty poor quality 3D scan performed by my drone...
Now I'm getting the extension segments made, as well as the internal stiffeners, then stitch this machine back together. The bend radius needs matching, which affects the flange lengths... trial and error to get the profile dialled in.
Lots of stringlines and straight edges will be required to ensure this all lines up just right. I couldn't find much detail online about this process so I'll document it fairly heavily in the hopes it helps someone else foolish enough to do this.
In Canada at least, finding identical material to the frame has proven impossible, so I went down the rabbit hole of learning about High Strength Low Alloy steels, grades and composition. For my chassis I've landed on the Canadian spec "350W" in 1/4 inch. It seems interchangeable with A572 Grade 50. They are a little higher in carbon content than the original material, and 10% lower in yield strength. However, I've seen test reports showing that the actual measured strength exceeds the minimum. Also, 1/4" is 6.35mm whereas my chassis is 6.0mm, but I'm calling it close enough. My second feasible option was a grade 80 material, far exceeding the strength of the stock material, which gave rise to concern about welding compatibility and failure of the weld. So I've decided a little less is better than a lot lot more. On top of all this will be the stiffening double skin frame overlapping bits.
And it's a bit overdue but the CAD model has finally been started, including a pretty poor quality 3D scan performed by my drone...
