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close this bookBending - Course: Technique of Working Sheet Metals, Pipes and Sections. Instruction Examples for Practical Vocational Training
View the document(introduction...)
View the documentPreliminary Remarks
View the documentInstruction Example 14.1.: Mounting Angle
View the documentInstruction Example 14.2.: Half-round Bracket
View the documentInstruction Example 14.3.: Hasp
View the documentInstruction Example 14.4.: Double Pipe Knee
View the documentInstruction Example 14.5.: Beaker Jacket
View the documentInstruction Example 14.6.: Beaker

Instruction Example 14.4.: Double Pipe Knee

Practise the rounding of a pipe with the pipe bending device and hammer.



Steel pipe

(380 MPa)


25 mm


about 1000 mm


Pipe bending device, smooth file 200 mm (flat and round), hand-type hacksaw, welding torch, machinist's hammer

Measuring and testing means

Steel rule, template R 400 and R 89, steel square

Auxiliary means

Vise, fine-grained sand, wooden stopper

Previous knowledge required

Manual material working: Measuring, testing, scribing, sawing, filing.

Sequence of operations


1. Prepare the working place and make available the working material.

Check completeness.

2. Calculate stretched length.

Subdivide total length into 5 partial lengths.

3. Saw pipe to length and deburr it.

4. Fill pipe with sand and close it with wooden stopper.

Only use dry and fine-grained sand.

After filling, compress the sand by knocking.

5. Bend radius of 400 without heating in the bending device.

6. Bend radius of 80 on the vise with the hammer by uniform heating.

Before bending, scribe length to be heated.

7. Check bendings.

- Accuracy to size

- Angularity

- Shape

Double pipe knee