MK Products Collets

In MK Products Python and Cobra gun systems, collets grip the contact tip or the gooseneck liner assembly to maintain precise wire alignment and secure electrical contact. Different collet sizes correspond to different wire diameters (0.030 in., 0.035 in., 3/64 in., 1/16 in., etc.) and to gun body styles. Using the wrong size collet allows the wire to wobble at the tip, causing inconsistent arc starts and accelerated tip wear.

Check the existing collet for a stamped part number or measure the wire bore diameter with a caliper. The part number will correspond to the wire diameter (e.g., 0.035 in., 3/64 in., 1/16 in.) and the gun model family (Python or Cobra). Lincoln's MK Products documentation lists the complete collet-to-gun compatibility matrix; when in doubt, provide the gun model number (e.g., K6042-1 for the 15 ft. air-cooled Python) to cross-reference.

Collets are wear items that should be inspected every time you change a liner or contact tip. Look for deformation, cracking, or a loose fit that allows wire play. A worn collet is a common but overlooked cause of erratic wire feeding — it effectively adds play at the critical current-transfer junction where the wire enters the gun. Replace at the first sign of physical distortion or when feeding becomes inconsistent despite a fresh liner and tip.

No — MK Products collets are proprietary to the Python/Cobra gun geometry. Generic or off-brand collets will not seat correctly, which can cause gas leaks, wire misalignment, and heat build-up at the connection point. Stick with genuine MK Products (KP-prefix) parts to maintain the system's designed wire-feed accuracy and current transfer.