Craftsman 113.201892 Spécifications télécharger pdf (Page 21)

UNDERCUT

OVER-LAPFED

_gure 13

Figure 14

BACK-UP STRIP

Figure ]5 Figure 16

Figure I7

HORIZONTAL WELDING

Horizontal welding refers to one type of butt weld between

two plates in a vertical plane. For practice, set up a plate

as for vertical welding and run straight beads across from

left to right (fig. 12). Use the some current settings as for

vertical-down welding and hold the rod as indicated with

a short arc. Move the rod in a straight line and deposit

a light bead. The rate of travel will depend upon the current

used. Too slow a travel will cause the bead to sag (fig. 13).

Practice with 3/32, 1/8 and 5/32-inch rods until a weft

formed bead can be macle with each size rod (fig. 14).

Sheet metal up to 1/16-inch thick con be butt welded from

one side. If the seam has numerous gaps, use a back-up

strip, allowing a slight gap between edges of 1/8-inch

thick metal and weld from both sides (fig. 15). All metal

3/16-inch thick and over should be beveled and welded

with a number of passes (fig. 16). Thoroughly clean each

bead before laying the next and use higher current than

for single-pass welching.

The appearance of a multiple-pass horizontal weld can be

improved by vertical down beads laid closely together.

Use a swift circular motion to the right; stowly downward

while welding (fig. 17).

OVERHEAD WELDING

Although overhead welding is generally considered diffi-

cult, do not become discouraged, as it is being done every

day by people who have taught themselves. Once the art

of maintaining a short arc has been mastered, the rest

will be easy.

Since there will be a shower of sparks, wear a leather jacket,

tight fitting cap and ear plugs and keep the practice plate

slightly higher than the top of your head when standing. To

keep sparks out of your glove, grasp the electrode holder as

indicated in figure 18 and hold the rod in a nearly vertical

position with a slight tilt to the right. Drape the cable over

your shoulder so its weight will not interfere with the use

of the electrode. Use 1/8-inch rods and a current setting the

same as for vertical welding, and move the rod in a straight

line without any weaving or whippir_g motions. A

reasonably fast rate of travel must be used_ to prevent the

bead from sagging and undercutting along the edges. Vary

the rate of travel and notice its effect on the size and

appearance of the weld. When you feel you can run a

satisfactory bead, try the side-to-side weaving motion and

deposit a thin weld approximately 3/4-i:nch wide. The

movement must be somewhat faster than for other

positions to keep the bead from sagging. (This method of

weaving is used only for the last pass on heavy welds where

improved appearance is necessary,)

The whipping motion is used where a gap exists between

the plates as it provides better penetration with higher

welding current. For practice work, set up two plates ap-

proximately 1/8-inch thick, allow|ng a gap between them.

Burn in deep for good penetration with 1/8 and 5!32qnch

rods, varying the plate size and gap distances.

Figure 18

Figure 19

Fillet welds for tap or tee-joints are most common in the

overhead position. Tack-weld two pieces of scrap iron

together to form a tee-ioint, and clamp in the overhec_d

position so one plate is held vertically (fig. 19). Hotd the

rod at angles indicated and deposit a [ight bead from left

to right without weaving or whipping movements. A slightly

higher current than used for overhead butt welds will be

necessary to get good penetration at the root of the weld.

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Craftsman 113.201892 Spécifications Page 21

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