Introduction
In previous session we learned about Tube fitting Installation procedure .In this session we are going to discuss about Tube cutting & tube bending
Tube Cutting
Tubing must be cut with a perpendicular cut (90˚).
There are two common methods of cutting tubes:
• Tube cutter
• Hacksaw
The use of a fine-toothed hacksaw (in guide block) is recommended for dimensions greater than 3/4” (20 mm).
When using a tube cutter:
1. Ensure that the cutting wheel is sharp and suitable for the material the tool will be used on.
2. Do not over tighten. Tubing can easily be deformed (become oval).
3. After every second turn of the cutter, tighten the handle by about 1/8 of a turn until the tubing has been cut.
4. After cutting, remove internal and external burrs with a tool. Clean all the metal shavings out of the tubing after removing burrs.
Tube Bending
L – Straight tube length required from end of tube to beginning of bend.
R – Radius of tubing bend as required or minimum allowed for specified wall thickness and tube size as recommended by bender manufacturer.
T – Tube outside diameter
Always use a bending tool suitable for the tubing’s size. It is recommended to use a bending machine when bending larger dimensions (e.g. from 20 mm) and thick wall tubing. It is good practice to measure up, mark and bend lengths one at a time. Remember to measure from centre line to centre line.
90 degree bend:
1. Place the tubing so that the mark lies directly below the 90 degree mark on the hand tube bender.
2. Depending on the type of bender, this is marked with 90 or ‘L’ (left).
3. If your reference measuring point is from the right, the ‘R’ (right) mark must be used.
4. Make sure the 0 marks on the hand tube bender are directly above each other and lock the tubing in place in the bender
5. Make sure that bending is in the right direction (use a help line).
6. Bend the tubing in a controlled manner to the 90 degree mark.
7. Check the angle. Experience shows that one has to compensate for tensions in the tube, approx. 1-3 degrees.
45 degree bend:
1. Place the tubing so that the mark lies directly below the 45 degree mark on the hand tube bender.
2. Lock the tubing in place in the bender.
3. Bend the tubing in a controlled manner to the 45 degree mark.
4. Check the angle