0 items in your basket
Total £ 0.00 EX VAT
Multi Process Welders
MIG Torches
TIG Torches
Welding Helmets
Welding Gloves & Clothing
MMA Electrodes
MIG Wire
Shop 55,000 Products
SERVICEDEPT.
RAPID BLOG
FEEDBACK
HIRE
Straight answers to common questions about choosing, fitting and looking after M8-thread MIG contact tips.
M8 is the diameter of the thread that screws the tip into the torch. Contact tips come with several thread sizes, commonly M6, M8 and M10, and the thread must match the torch's tip holder.Larger tips are generally found on torches built for heavier current, but the thread size does not tell you a torch's rating. Check the torch's data plate and parts list for the correct tip, including its length and body diameter, as these differ between designs.
For medium to high current, harder copper alloy tips are the usual standard because plain copper softens at relatively modest temperatures. The alloy has slightly lower conductivity, which normally does not matter in practice.For demanding, long-duty work, especially with flux-cored wire, tips with a hardened core and a special surface coating are used, as the coating helps spatter not stick. Plain copper is better suited to lower current. Match the material to your current, duty and wire.
Yes. Aluminium wire is soft and expands more than steel wire when heated, so tips for aluminium usually have a slightly larger bore to prevent the wire gripping. They are normally marked for aluminium use.The tip material matters too: copper tips pass current to aluminium wire better than harder alloys. Pair the tip with a smooth-bore plastic-based liner and suitable drive rolls, and avoid steel-wire tips for aluminium.
Choose the tip whose bore is stated for your wire diameter, which is printed on the wire spool. The tip is usually marked with its bore size as well.An oversized tip with a smaller wire causes arcing and speeds up wear. When you change wire size, change the tip, the drive rolls and the liner together, as each one is sized to the wire. A liner that is too big for the wire can cause the wire to tangle.
Look at the hole. The wire wears the bore into an oval shape, which is the first and most telling sign. You may also see an unsteady arc, difficult starts, wire that feeds in fits and starts, or wire welded into the tip.Change tips by their condition rather than a fixed schedule, and do not file or ream a worn one. On heavier work, wire travels through the tip in large amounts, so tips wear steadily and should be inspected often.
Hand-tighten the tip until it seats, then snug it with the proper tool. Avoid over-tightening, which can cause feeding issues and damage the threads.A loose tip overheats and wears out sooner, and blue or purple threads are a sign it has been running hot. If it keeps working loose, check the tip holder for damage, make sure you have the right thread and seat, and replace worn parts.