Where do the holes and the seam sit on the sheet?

The holes at a quarter and three quarters of the stretch-out, and the seam ninety degrees from both — neither over a hole nor between them, but where the shell has plenty of solid metal.

Can the two branches have different diameters?

Not in this part: both holes come out alike. For branches of different sizes, calculate the single-hole shell twice and transfer the second marking — what you lose is the relative position arriving ready-made.

Which diameter do I enter?

The HOLE, as on the single-hole shell — for a branch set on top it goes at the branch's bore, for one set in, at its outside diameter.

Why can't the hole be as large as the shell?

Because each hole opens up to the width of the arc it occupies, and at equality that is half a turn. The two holes would touch and no shell would be left between them — the part stops existing before the arithmetic fails, which is why the guard is strict.

4-Way Cross Shell development

What it is

The run pipe of a cross, with both holes. A cross is made of three parts — this shell and the two branches, which are the pipe branch part in this catalogue. What this part gives, and the single-hole shell does not, is the RELATIVE POSITION of the two holes on the flat sheet: exactly what you cannot get by using the single-hole part twice.

Where it is used

Crosses in pipework, headers with opposed take-offs, distribution manifolds, twin runouts on air or steam lines.

Measurements the calculation needs

D2 Outside diameter of the shell
H Length of the shell
D Diameter of the holes (both alike)
ANG Angle of the branch to the axis
DV Divisions
THK Plate thickness

Worked example

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

Outside diameter of the shell	400 mm
Length of the shell	600 mm
Diameter of the holes (both alike)	150 mm
Angle of the branch to the axis	90°
Divisions	32
Plate thickness	6 mm
The flat pattern fits a plate of	1238 × 600 mm

Result of the example

Plate	1238 × 600 mm

4-Way Cross Shell flat pattern: drawing of the template with the worked example dimensions — Cut lines in purple, welds in green and reference lines in orange. Plate 1238 × 600 mm.

Frequently asked questions

Where do the holes and the seam sit on the sheet?: The holes at a quarter and three quarters of the stretch-out, and the seam ninety degrees from both — neither over a hole nor between them, but where the shell has plenty of solid metal.
Can the two branches have different diameters?: Not in this part: both holes come out alike. For branches of different sizes, calculate the single-hole shell twice and transfer the second marking — what you lose is the relative position arriving ready-made.
Which diameter do I enter?: The HOLE, as on the single-hole shell — for a branch set on top it goes at the branch's bore, for one set in, at its outside diameter.
Why can't the hole be as large as the shell?: Because each hole opens up to the width of the arc it occupies, and at equality that is half a turn. The two holes would touch and no shell would be left between them — the part stops existing before the arithmetic fails, which is why the guard is strict.

4-Way Cross Shell dimension drawing: D2 (Outside diameter of the shell), H (Length of the shell), D (Diameter of the holes (both alike)), ANG (Angle of the branch to the axis), DV (Divisions), THK (Plate thickness), marked on the part

Calculate a 4-Way Cross Shell

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