4623R - Insulator cap

Keep Your MIG Gun Running Smoothly with the Bernard 4623R

Every welder knows that the front-end consumables of a MIG gun take the most abuse, and the nozzle insulator is often the unsung hero of the assembly. The Bernard 4623R AccuLock™ Nozzle Insulator is the genuine replacement part you need to keep your Miller® MDX-250 or Bernard™ BTB™ MIG gun operational and safe. Over time, heat, spatter, and general wear can degrade your insulator, leading to loose nozzles, poor gas coverage, or even frustrating electrical shorts if the nozzle touches your base metal. Swapping out a damaged insulator with a fresh 4623R restores the tight, secure fit of your nozzle and ensures your shielding gas is directed exactly where it needs to go.

This insulator is designed for versatility and ease of use. Whether you are running a Miller MDX-250 in a fabrication shop or using a custom Bernard BTB gun on a production line, this single part fits the bill. It works seamlessly with both AccuLock™ S and AccuLock™ MDX diffusers, meaning you don't have to worry about matching the insulator to the specific diffuser type within the AccuLock family. The installation is straightforward—simply remove the nozzle, unscrew the old insulator (or pull it off depending on the specific assembly state), and seat the new one. It’s a quick fix that can prevent significant downtime.

Using genuine Bernard and Miller parts like the 4623R ensures that you aren't fighting your equipment. Generic knock-offs often suffer from poor heat resistance or slight size variations that cause the nozzle to rattle or fall off. The 4623R is built to withstand the heat of 250+ amp welding, maintaining its shape and insulating properties shift after shift. If you are noticing your nozzle wobbling or seeing signs of arcing on your nozzle, check your insulator. Keeping a few of these 4623R insulators in your toolbox is a smart move for any serious welder or maintenance team looking to maintain high-quality welds and efficient equipment performance.