Lincoln Bester 215MP Parts FAQs
Practical answers on the torch consumables, wire feed parts and holder spares used with a multi-process MIG welder, and how to match them to your machine.
How do I tell when a MIG contact tip is worn out?
The most telling sign is the hole: when the bore is no longer round and has become oval or eroded, the tip no longer feeds the wire precisely and should be replaced. Strong discolouration from overheating is another reason to change it.
In use, a worn tip shows up as an erratic arc, wire that snags or feeds unevenly, or the wire burning back into the tip. A blackened or spatter-covered tip is not always a reason to replace it, and a fixed swap schedule is less reliable than looking at the bore. Check the tip each time you change the wire spool.
How tight should a contact tip be, and does it matter?
It matters a lot. A tip that is loose, or not sitting flat on its holder, gives a poor electrical connection, which makes it overheat and wear quickly. The tip should sit flat on the tip holder with the threads in full contact, tightened with a suitable tool.
As a rule, screw it in by hand and then snug it with the correct tip tool; over-tightening can damage the tip or the holder. Do this with the torch cold and the machine isolated, and make sure the tip, holder and diffuser are all clean and fully seated before you start welding.
How do I choose the right liner for my wire?
The liner guides the wire from the feeder to the contact tip and must suit both the wire material and its diameter. Hard wires such as steel and stainless generally use a spirally wound steel liner, while soft wires such as aluminium and copper generally use a PTFE liner. A liner with too large a bore gives the wire too little support, so it can fold and tangle in the feeder.
So choose by wire type first, then by the diameter range printed on the liner, and make sure it is long enough for your torch. Do not rely on colour codes alone, as these can differ between makers. Check the torch manual for the liner type it takes.
How do I fit and cut a new liner properly?
Cut the liner with a sharp side cutter for a clean edge and remove any burrs, because burrs shave the wire and cause feeding trouble. A common reason for a liner wearing out early is cutting it too short. The liner should seat flush against the contact tip, with slight pressure when the tip is screwed in.
Keep the cable as straight as possible while fitting, and compare the new length against the old one and the torch manual. A pull test helps: if you cannot pull the wire through by hand with the feed rolls released, the wire or liner needs attention. Isolate the machine first.