The next step is to lay out the dimensions on the tubes. I use a blue layout spray ink and mark the cuts with a fine scribe. Next I cut the tubes to length with a cut off disc. To miter the tubes I do things a little differently now. I used to use bi-metal hole saws to miter tubes on a lathe using a tube holder in place of the tool post. Now I use a mill based belt sander I built to work with very thin walled True Temper S3 tubes. It makes for very accurate cuts in any diameter required. You just need to make a simple round spindle for each size.