How to rebuild a busted CAT gear WITHOUT welding!
Here we have the circle drive gear of a heavy Caterpillar motor grader. The top part of the teeth is worn down to almost nothing, and for an official dealer, this means only one thing: buying a new part for crazy money and weeks of machine downtime. But local mechanics solve the problem in a single day.
Check out this hardcore approach. First, using an oxy-acetylene torch, the welder cuts a new blank from a thick sheet of armor-grade steel. Next comes the precision work on a heavy lathe. The worn part of the original gear is ruthlessly turned down to a smooth shaft, and an external thread is cut into it. Then, a hole is drilled into the new "cap," an internal thread is tapped, and the two parts are screwed together dead-tight.
The master undoubtedly cut the thread considering the drive's direction of rotation. Under load, this gear won’t loosen; instead, it will permanently self-tighten. Tearing this assembly apart is practically impossible.
After the final turning, a new kind of madness begins. Using an ordinary angle grinder, the master manually carves the involute profile of the new teeth, using the intact bottom half of the gear as a template.
The thing is, this gear rotates at a very low speed but transmits massive torque, and the entire system is heavily bathed in thick grease. For such low-speed components, micron-level precision of the tooth profile simply isn’t necessary. Having the correct pitch and depth is enough, which is exactly what the master achieved by extending the lines of the old teeth.
A few final strokes of black paint, and the part is indistinguishable from the factory original.
What do you think of this hardcore practice? Let me know in the comments and hit that like button!#caterpillar, #heavyequipment, #gearrepair, #machining, #lathe, #metalworking, #restoration, #industrialengineering, #mechanic, #heavyrepair, #engineering, #custommachining, #manualmachining, #welding, #shorts