Fabrication of tube assemblies consists of tube cuttings, deburring, bending, and tube joint preparation. The procedures found in this chapter are for instructional purposes only. When fabricating tube assemblies, refer to the Manual, NA01-1A-20.

When you cut tubing, the objective is to produce a square end free from burrs. Tubing should be cut with a standard tube cutter, or the Permaswage chipless cutter.

Place the tube in cutter with cutting wheel at the point where the cut is to be made. Apply light pressure on tube by tightening adjusting knob. Too much pressure applied to the cutting wheel at one time may deform the tubing or cause excessive burrs. Rotate the cutter toward its open side (fig. 6-5). As the cutter is rotated, adjust the tightening knob after each complete turn to maintain light pressure on the cutting wheel.

Permaswage Chipless Cutter 

Select the chipless cutter according to tubing size. Rotate cutter head to accept tubing in cutting position. Check to ensure the cutter ratchet is operating freely and the cutter wheel is clear of the cutter head opening (fig. 6-6).

Center the tubing on two rollers and cutting blade. Use the hex key provided with the kit to turn the drive screw in until the cutter wheel touches the tube. Tighten the drive screw one-eighth to one-fourth turn. Do not overtighten the drive screw. Overtightening can damage soft tubing or cause excessive wear or breakage of the cutter wheel in hard tubing. Swing ratchet handle back and forth through the available clearance until there is a noticeable ease of rotation. Avoid side force on cutter handle. Side force will cause the cutter wheel to break. Tighten the drive screw an additional one-eighth to one-fourth turn, and swing ratchet handle back and forth, retightening drive screw as needed until cut is completed.

Figure 6-6.Permaswage chipless cutter.

If neither tube cutter (standard or Permaswage) is available, a fine-tooth hacksaw should be used to cut tubing. A convenient method for cutting tubing with a hacksaw is to place the tube in a flaring block and the clamp block in a vise. After cutting the tube with a hacksaw, remove all saw marks by filing the tube.