BUCKET G 1246616 - Caterpillar

Cutting And Beveling Of Sprocket
1. Remove the sprocket as shown in the Service Manual and place it on a welding fixture similar to the one shown, with the inside of the sprocket down. Centering cone (1) on center shaft (2), along with adjustable hub support (3), will permit quick centering for all size sprockets. The time needed to put a sprocket into position for welding can be greatly decreased if the fixture has a rollover feature so that the sprocket does not need to be removed at any time during the welding operation. This is especially adaptable to spoke welding.
An accumulation of any flammable substance may ignite and cause personal injury. Wipe away any spilled oil or other flammable substance before cutting with an air carbon arc torch or similar tool.
2. Use an air carbon arc torch or similar tool to cut the rim off of the worn sprocket to dimension B from the Standard and Snow Sprocket Charts.3. Chamfer the hub or spoke ends with an oxy/fuel torch with beveling tip to the correct joint shape as shown in the joint shapes illustrations. The joint shape is referenced in the Standard and Snow Sprocket Charts.4. Use a grinder to assure the surfaces are clean and all slag has been removed.Reference Dimension Locations
Joint Shapes
Procedure For Spoke Welding
Excess heat input in the spokes and the rim and/or uneven cooling of the hub and rim can cause stress concentrations that will usually cause cracks in the rim and the weld. Heat input can be controlled effectively by closely following the procedures in this instruction.
The repair surfaces must be clean. Remove all foreign material before welding.1. Put the replacement rim and hub on the fixture in welding position according to dimensions B, C, D and E from the Standard and Snow Sprocket Charts. Use dimensions B and C under the Spoke Welding heading.2. Put numbers on the spokes clockwise in a sequence of 1, 9, 6, 3, 8, 5, 2, 7 and 4. Before welding, be sure the weld zone on the rim and hub are preheated to 149°C (300°F). The welding fixture should be located in an area free from drafts. Use dry, low hydrogen electrodes according to AWS Specification E7018 (available from Caterpillar [1U5232 - 3.18 mm (.125"), 1U5234 - 4.76 mm (.188")]). Do not use any electrodes that have been open to the atmosphere for more than four hours.3. Using 3.18 mm (.125") electrodes and a setting of 120-145 Amperes, DC reverse polarity, weld one pass on spokes numbered 1, 2 and 3.4. Clean the welds and weld one pass on the same spokes with 4.76 mm (.188") electrodes at 230-250 Amperes.5. Using 3.18 mm (.125") electrodes and 120-145 amperes, weld one pass on spokes 4, 5, 6, 7, 8 and 9 in that order.6. Turn the sprocket over and clean the weld joints. If the gap is too small to clean, scarf out with air carbon arc equipment. For minimum heat concentrations, do not weave the