A track welding machine needs a rail laid and aligned before the first arc is struck. On a long seam that is time well spent. On a stiffener, a bulkhead or a run of short fillets it is most of the job.

Trackless machines skip that step. Powerful permanent magnets hold the carriage to the workpiece, guide wheels track the web or the flange, and the machine is welding within a minute of being lifted out of the case. Pull the handle and the magnet releases for repositioning.

The K-BUG family covers most of what a fabrication shop needs. A compact single-torch tractor for flat fillets. A dual-torch machine that welds both sides of a stiffener simultaneously. An all-position oscillating machine with a wireless remote and five weave patterns. A machine that runs along a vertical wall inches from the floor. Two of them run on 18 volt batteries, so there is no power lead to drag or trip over.

Alongside the K-BUGs sit two purpose-built machines: the Uni-Bug III, which clamps to a profile rather than magnetising to a plate and comes in kits matched to flat bar, angle, channel, I-beam, T-profile and bulb flat; and the Stiffener Welder, which welds both sides of an I, T or angle stiffener at once on flange widths up to 12 inches.

The honest comparison against track: trackless wins when laying rail costs more time than the weld saves, and when the joint is short, repetitive or awkward to reach. Track wins on long seams and on anything where the same weld has to be identical over many metres. We sell both.