Many sign companies and manufacture use the Sbap-On/ Systematics mig machines. The Long-John Spool Gun has a custom nine-inch barrel designed for fabrication of aluminun channel letters. The barrel is 0.750 in diameter. This uses standard 4 spools of wire. The Long John Direct is unique in the "retro-fit" spool gun market.
It attaches directly to Snap-On® Muscle MIGs (and most Systematics®) MIG welders. It requires no adapter or separate gun power supply: just "plug and weld"! Revolution Direct is the spool gun solution for Snap-On® Muscle MIG, Snap-On® YA212, FM 140 (140A), MP MIG 140, 175, or 250 welder, Systematics FW112, SCS112, or MPG 3 welder or wire feeder.The advantage of the electronic control is simple; at the slowest speed (1RPM), you have full motor torque. The control assures that you have consistent wire feed speed at any speed setting with all sizes of wire.
The Long John spool gun uses the industry standard 4-inch spools of wire available anywhere! Aluminum, mild steel, stainless steel, copper, silicone-bronze, aluminum-bronze and many more alloys are available on these standard-size spools. Many other guns use only a proprietary spool design that locks you into expensive OEM wire supply. If your welding machine has the MIG gun receptacle pictured below, then the Revolution Direct gun will install on your machine -- no adapter needed. The item "WELDMART RETROFIT CHANNEL LETTER SPOOL GUN (NINE INCH BARREL) FOR SNAP-ON WELDER" is in sale since Saturday, September 30, 2017. This item is in the category "Business & Industrial\CNC, Metalworking & Manufacturing\Welding & Soldering Equipment\Welding\Other Welding Equipment". The seller is "m5090cld" and is located in Cleveland, Texas. This item can be shipped worldwide.