HOT ROD LINCOLN

If you hear the word “Caterpillar,” your first thought is probably a bulldozer. However, you might be surprised to know Cat built engines for marine and industrial purposes as well. In 1955, they branched out to service the welding markets with a unique unit.

The full story is unclear, but late in 1954, plans were made to produce a welder powered by a Cat engine. Cat engineers teamed up with Lincoln Electric in Cleveland, Ohio, to produce a powerful 400-amp welder powered by a Cat D315, four-cylinder diesel. They called it the Cat Twin Arc-welder because it placed two 300-amp, 40-volt NEMA Lincoln generator heads end-toend behind the Cat engine, with a souped-up 1.5 KW exciter to run them both. Generally, the unit was intended to allow for simultaneous operation of two welders using up to 300 amps each, but by bridging to the two units together and running them in parallel, Cat rated it for 400 amps.

Even though he has had a career in welding, current owner Mike Schreiber had never seen a rig like this. That’s been true of pretty much anyone else who has seen it. Mike, a well-known Caterpillar collector and restorer, is well-versed in Cat products, but this rig was a bit of a mystery. He contacted both Caterpillar and Lincoln and learned that the D315 engine powering it was built in May of 1955—the same for a companion welder found at the same time. The generator head was one of a 19-unit order from Lincoln built around the same time. Cat produced a brochure and a parts book, but it seems this welder was not a

The welding unit has two sets of controls for each 300-amp head. If you can’t get the job done with 300 amps, you can add some bridging cables and run them in parallel for 400 amps. It isn’t clear why you can get the full 600 from doing that, but what do we know?

uthe head of the oversized exciter sticks out of the cable end, but again, you can see the welding lead connections for the two welders. It’s here that you would bridge the two heads to get more than 300 amps. The unit still had the remnants of the Contracting & Material Company decal, so Mike had it reproduced to offer a little historical context.