Sweep gores
Gores for a sweep or any elbow you know the turning radius of. The heel and throat formulas are done for you, with your laps added.
Inputs
From the Knauf chart, or type your own
2R, 3R, 5R... fills the turning radius from the line size
Bend centre to the pipe centreline. Field verify any sweep not on the drawing.
Elbow
¾" to 1" is normal (bead and crimp)
½" is normal, ⅜" minimum
0Miter heel
0Miter throat
0Gore heel (+ heel lap)
0Gore throat (+ throat lap)
0Stretch-out (circumference + 3")
0Space (raw circumference ÷ parts)
Transfer points
| Line | Each side of centreline 1/16" | Decimal |
|---|
Gore pattern
- Cut the metal to the stretch-out length, . Draw a centreline down the middle.
- Mark a 1½" end lap at each end, leaving the raw circumference between them.
- Divide the raw circumference into equal spaces and number them as shown: seam side, up to the heel, down to the throat (0), back up to the seam side.
- Mark each distance from the table on both sides of the centreline on its line. Join the marks in a smooth curve.
- Punch a reference dot at the side lines and the heel. Use them to line up the gores and to start and stop the bead and crimp.
- Trace out gores. Crimp first, then bead. Fade the crimp on and off, heel half only.
Method: Advanced Metal Jacketing (IIIATF), Task B.7, Sweeps. Miter heel = (radius + ½ OD) × π ÷ 2 ÷ gores, throat the same with radius − ½ OD (90°). Check the first piece on the job before cutting a batch.