Step 07.30 — Set the 150 mm measuring span¶
Step 30 of 39 with a helper · Chapter 07 — A/B belts and tensioning
Parts: none.
Do: Move the X extrusion forwards by hand until the XY joint idler centres are 150 mm from the front idler centres. Measure centre to centre with the rule on both sides, with the gantry square to the frame, not skewed.
Check
150 mm on the left and 150 mm on the right, measured to the same features.
Helper Holds the rule between the two idler centres and reads the number aloud on each side.
What you're looking at
The two idlers a belt runs between, one in the XY joint, one in the front idler block, and the free belt between them that you pluck. A plucked belt's pitch depends on the span, so the figure means nothing without it.
Provisional: the squaring procedure starts by releasing this tension completely (V2 gantry squaring, step 5; survey §4.4 #2 and §5.2 W1). What you set here only needs to be good enough to home, QGL and run the bring-up in Ch 13; Ch 14 Step 14.4 owns the final number.
Tip
The CAD shows a parked 250 machine, not the measuring pose. Take which two centres from the picture, take the number from the rule.
Source: Voron docs § Secondary printer tuning — A/B Belts · Voron manual p.141 · Video: Part 6 @0:10:08 · CAD: Voron 2.4r2 STEP @ de7e89d