Gore layout
Metal jacket gores for a mitered elbow, laid out the trade way: miter heel and throat from the ASTM C450 chart, half circle at the insulation OD, 16 segments on the layout line. Pick the line size, thickness and radius; the transfer points are done for you.
Inputs
Transfer points
| Line | Above and below 1/16" | Decimal |
|---|
Gore pattern
Shaded ends are the laps. Orange lines are #5 (bead and crimp) and #9 (centre). Height is stretched so the shape reads on a phone; mark from the table.
- Draw the layout line long and divide it into 16 segments of . Add one segment at each end for the lap.
- Number the lines 6 down to 1, up to 9, and back down to 4. Square a line through each mark.
- Mark each distance from the table above and below the layout line on its numbered line. Join the marks.
- If a lap is more than 2", trim it back to 2" at each end.
- Mark the #5 lines as bead and crimp start and stop, and #9 as the centre mark.
- Label the gores LEFTS and RIGHTS with the exterior surface facing out.
Reference drawing
The drawing the numbers come from: half circle at the insulation OD, each quarter split in 4, projected square down to the line between the throat and heel points. Throat on the left, heel on the right.
Method: IIIATF Metal Layouts, Elbow Gore, Method 1. Gore count, miter heel and miter throat from ASTM C450 (same data as the Mitered ells page). Insulation OD from the Knauf Earthwool 1000° chart. Check the first gore on the fitting before cutting a batch.