Do both angles have to match?

No. Each opening takes its own angle, which is the point of the part: solving two different offsets in one cut of plate.

Why does the result come in two flat patterns?

The part is delivered as two halves that together close the tube. Each half can be checked separately against the single-cut cylinder.

Double Cut Cylinder flat pattern

What it is

A rolled shell cut at an angle on both ends, each with its own angle. Developed, it gives two waves — one per edge — which can differ in height and phase. It is the part that clears two offsets with a single length of tube.

Where it is used

Connecting runs between misaligned equipment, intermediate gores of field-assembled bends, adaptations to existing pipework.

Measurements the calculation needs

D Outside diameter of the tube
X Straight run between the two cuts
ANG1 Cut angle of the first mouth
ANG2 Cut angle of the second mouth
DV Divisions
THK Plate thickness

Calculate with your own measurements

No account needed: enter the measurements in millimetres or inches and get the figures and the drawing. The scaled PDF template, the DXF for the cutting table and the 3D model take a free account.

Diameters and sides are outside measurements. The flat pattern already allows for the plate thickness, working on the mean line.

Units: mm inches

Worked example

The values the form comes pre-filled with, run through the tool itself:

Outside diameter of the tube	200 mm
Straight run between the two cuts	100 mm
Cut angle of the first mouth	35°
Cut angle of the second mouth	35°
Divisions	16
Plate thickness	10 mm
The flat pattern fits a plate of	597 × 187 mm
Flat patterns produced	2

Result of the example

Plate 1	597 × 187 mm
Area and weight	0.072 m² · ≈ 5.6 kg in 10 mm steel
Plate 2	597 × 187 mm
Area and weight	0.072 m² · ≈ 5.6 kg in 10 mm steel

Double Cut Cylinder flat pattern: drawing of the template with the worked example dimensions — Cut lines in purple, welds in green and reference lines in orange. Plate 597 × 187 mm.

Ordinate table

#	Position on the plate	Element height
1	0 mm	53.5 mm
2	37.3 mm	58.6 mm
3	74.6 mm	73 mm
4	111.9 mm	94.6 mm
5	149.2 mm	120 mm
6	186.5 mm	145.5 mm
7	223.8 mm	167.1 mm
8	261.1 mm	181.5 mm
9	298.5 mm	186.5 mm
10	335.8 mm	181.5 mm
11	373.1 mm	167.1 mm
12	410.4 mm	145.5 mm
13	447.7 mm	120 mm
14	485 mm	94.6 mm
15	522.3 mm	73 mm
16	559.6 mm	58.6 mm
17	596.9 mm	53.5 mm

Assembly notes

Weld the sheets with the longitudinal seams 180° apart, not lined up. Lined up, the piece assembles into a different shape — and the longitudinal seam crosses the circumferential one.

Guides about this part

How to lay out a mitre-cut pipe: paper template, sine wave and ordinate table

Frequently asked questions

Do both angles have to match?: No. Each opening takes its own angle, which is the point of the part: solving two different offsets in one cut of plate.
Why does the result come in two flat patterns?: The part is delivered as two halves that together close the tube. Each half can be checked separately against the single-cut cylinder.

Double Cut Cylinder dimension drawing: D (Outside diameter of the tube), X (Straight run between the two cuts), ANG1 (Cut angle of the first mouth), ANG2 (Cut angle of the second mouth), DV (Divisions), THK (Plate thickness), marked on the part

Calculate here, no account Open the full calculator

You can work out the figures right here, with no account. PDF, DXF, 3D and history take an account — free, with unlimited calculations.