Tweco 39 CutMaster - Manual (Page 40)

cutmaster 39
OPERATION 4T-4 Manual 0-4975
Dross
When dross is present on carbon steel, it is com-
monly referred to as either “high speed, slow speed,
or top dross”. Dross present on top of the plate is
normally caused by too great a torch to plate dis-
tance. "Top dross" is normally very easy to remove
and can often be wiped off with a welding glove.
"Slow speed dross" is normally present on the bot-
tom edge of the plate. It can vary from a light to
heavy bead, but does not adhere tightly to the cut
edge, and can be easily scraped off. "High speed
dross" usually forms a narrow bead along the bottom
of the cut edge and is very difficult to remove. When
cutting a troublesome steel, it is sometimes useful
to reduce the cutting speed to produce "slow speed
dross". Any resultant cleanup can be accomplished
by scraping, not grinding.
4T.07 Hand Torch Operation
Standoff Cutting With Hand Torch
NOTE
For best performance and parts life, always use the
correct parts for the type of operation.
1. The torch can be comfortably held in one
hand or steadied with two hands. Position
the hand to press the Trigger on the torch
handle. With the hand torch, the hand may
be positioned close to the torch head for
maximum control or near the back end for
maximum heat protection. Choose the
holding technique that feels most comfort-
able and allows good control and move-
ment.
NOTE
The tip should never come in contact with the
workpiece except during drag cutting opera-
tions.
2. Depending on the cutting operation, do one
of the following:
a. For edge starts, hold the torch perpen-
dicular to the workpiece with the front
of the tip on the edge of the workpiece
at the point where the cut is to start.
b. For standoff cutting, hold the torch 1/8
- 3/8 in (3-9 mm) from the workpiece as
shown below.
A-00024_AB
Shield Cup
Torch
Standoff Distance
1/8" - 3/8" (3 - 9mm)
Standoff Distance
3. Hold the torch away from your body.
4. Slide the trigger release toward the back
of the torch handle while simultaneously
squeezing the trigger. The pilot arc will
start.
Art # A-03962
Trigger
Trigger Release
5. Bring the torch within transfer distance to
the work. The main arc will transfer to the
work, and the pilot arc will shut off.
NOTE
The gas preflow and postflow are a characteristic
of the power supply and not a function of the
torch.