scrap and finished parts and can pierce holes to make inside cuts without operator assistance.
What degree of dimensional accuracy can be maintained in cutting machines?
About
How should you adjust the torch tip preheat orifices in a normal cut?
If there are two preheat orifices, the tip should be rotated in the torch so that a line drawn between orifices will be perpendicular to the cut line. If more orifices, two should fall on the cut line and the rest divided equally on each side of the cut line. This symmetrical preheating improves the quality of the cut. See Figure 2–16.
Figure 2–16Location of preheat orifices in relation to kerf for a normal cut
For making a bevel cut how should you adjust the preheat orifices?
See Figure 2–17.
Figure 2–17Location of preheat orifices in relation to kerf for a bevel cut
What is the best torch technique to start a heavy cut?
See Figure 2–18.
Figure 2–18How to start a cut on heavy steel
What are the proper terminating conditions when making a heavy cut so as not to let the effect of drag permit the cutting action to skip a small triangular area at the bottom of the end of the cut?
As the end of the cut nears, tilt the torch away from the direction of travel. This permits the bottom of the cutting action to proceed ahead of the top cutting action and eliminates premature breakout of the flame which leaves a triangle at the end of the cut. See Figure 2–19.
Figure 2–19How to complete a cut on heavy steel
What is the easiest way to remove a rivet with a cutting torch?
Follow the steps in the Figure 2–20.
Figure 2–20Steps to remove rivet
How can a countersunk rivet be removed?
See Figure 2–21.
Figure 2–21Steps to remove a countersunk rivet
What are two ways to pierce steel with OFC?
•Begin by preheating the material in the pierce location to a dull red color, kindling temperature, with the torch perpendicular to the metal. When metal becomes dull red, slightly raise the torch from the surface and angle the tip away from perpendicular. This prevents the slag blown back from the surface from landing on or in the torch tip. Then squeeze the oxygen lever to start cutting action. As soon as the material is completely pierced, restore the tip to perpendicular and the preheat flame to just above the surface. Complete cutting the opening wanted.
•If a small hole is wanted and the surrounding material is to be protected from cutting action, drill a
Figure 2–22Piercing steel
What is the best way to cut out a circle?
Pierce the material inside the circle and away from the finished edge. When cutting action is established, extend the cut into a spiral and begin cutting the circle itself, Figure 2–23. With small circles to avoid damaging the finished edge, drill a
Figure 2–23Cutting a circle
What is the easiest way to sever an I-beam?
Follow the numbered steps in Figure 2–24.
Figure 2–24Severing an “I” beam
What is the AWS designation for oxygen lance cutting?
The abbreviation for oxygen lance cutting is LOC.
What is an oxygen cutting lance and how is it used?
An oxygen lance is a length of steel pipe connected to a source of oxygen. An oxyacetylene welding or cutting torch is used to bring a spot on the work up to ignition temperature. The torch is then removed and the lance pipe end placed over the heated spot and the oxygen supply opened. The lance cuts through the work like a large cutting torch. The steel lance pipe is usually
Figure 2–25Oxygen lance process
Trouble Shooting
What causes a bell-mouthed kerf?
Excessive oxygen pressure, see
