How to Prepare Tube Ends (Fittings)

For proper tube preparation, you will need a tube cutter or a hacksaw and tube saw guide, a tube deburring tool, a marker, a tape measure, and proper personal protective equipment.

Before starting, be sure to wear safety glasses to prevent injury. If using a hacksaw, wear cut-resistant gloves.

Before cutting, inspect the tube for dents, scratches, and other damage. If the tubing is damaged, cut off the damaged section or use different tubing. Do not use damaged tubing. Scratches that can be detected with a thumbnail are too deep, and the damaged area should be cut off.

Also, ensure the tubing is round. Flattened or oval tubing will not fit properly into the tube fitting and should not be forced to fit. If the tubing is not round, it should not be used.

Be sure to read the lay line to validate the size, wall thickness, and material specification of the tubing.

After inspecting the tubing and reading the lay line, measure and mark the tubing where you want to cut it.

The Swagelok tube cutter is designed to cut tubing materials from 3/16 to 1 in. or 4 to 25 mm OD.

To use the tube cutter, position the marked tubing between the rollers and cutting wheel. Turn the handle until the wheel touches the tubing. Advance the handle an additional 1/16 turn. The handle knobs are spaced in 1/8-turn increments; use them for reference points.

Rotate the cutter around the tube. When cutting stainless steel or other alloys, advance the handle 1/16 turn after every second rotation. For softer materials, such as copper, advance the handle after each rotation. Continue until the tubing is cut through.

Always use a sharp wheel, since this is the best way to minimize burring. Replace the wheel if it is dull.

Depending on the size or material type of the tubing, a tube cutter may not always be the best tool. A hacksaw is useful for cutting tubing with a very small diameter, a thick wall, or a diameter too large for the Swagelok tube cutter.

Once you determine the overall length, mark the tubing and align it in the cutting slot. To use a hacksaw, properly secure the tubing using a tube saw guide and align your cut mark in the cutting slot. Using a hacksaw with at least 24 TPI (teeth per inch), cut through the tubing. A hacksaw with a higher TPI may make cutting easier.

The burrs on tubing cut with a hacksaw are different from those made with a tube cutter. Regardless of how you cut the tubing, you must remove all burrs, both on the outside diameter and inside diameter, prior to installation. Failure to do so may affect the fitting sealing capability and system cleanliness.

The Swagelok tube deburring tool has two ends. One is for the inside diameter and the other is for the outside diameter. The tool is for 3/16 in. inside diameter to 1 1/2 in. outside diameter and 4 mm inside diameter to 38 mm outside diameter stainless steel, steel, and hard alloy tubing.

To deburr the outside diameter of tubing, place the deburring tool over the end of the tubing with the blades on the outside. Rotate the tool in a clockwise direction for 4 to 5 revolutions. If burrs still remain, continue the process until the burrs have been removed.

To deburr the inside diameter of tubing, place the deburring tool over the end of the tubing with the blades on the inside. Rotate the tool in a clockwise direction for 4 to 5 revolutions. If burrs still remain, continue the process until the burrs have been removed.

To remove excess cutting and contamination, wipe the deburred end of the tube clean with a cloth. If there is excess oil on the tubing, wipe the tubing with rubbing alcohol to remove it. You can also clean the tube with dry compressed air before use unless it will be used for welding. Compressed air may contain moisture.

The deburred tube end should have a uniform edge break with no burrs. Internal and external chamfers should not exceed half the wall thickness of the tubing. If they do, the tubing is too thin.

After you have cleaned and inspected the tubing, it is now ready for installation.