Any Miter Cut-back Calculation in 5 Seconds.

Discover the 5-second trick every pipefitter needs for any miter cut back calculation.
For a 4" pipe with 4 cuts, write 44 and divide by 4 = 11mm cut back—instant!
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Works for any pipe size up to 9 cuts; matches full circumference × angle/360 formula exactly.
Mark reference lines, offset by cut back top/bottom, assemble for smooth bends every time.