Lincoln Electric KP2746-1 is the 350A air-cooled, thread-on Magnum PRO brass gas diffuser. It is not the similarly numbered slip-on KP2746-2 or the smaller 100A KP3076-1. Order the KP2746-1 only when the parts list for your actual gun and front-end nozzle system calls for that exact number. The connector and amp rating in a marketplace title are not enough to verify a replacement.
Arc Weld currently lists the Lincoln KP2746-1 single gas diffuser as an active product, with an exact SKU and positive available inventory at the time checked. Inventory may change after this article is prepared; the linked product page is the place to confirm the current offer and package before ordering.
What makes KP2746-1 different from the other diffusers?
Lincoln’s official Magnum PRO diffuser selection guide lists KP2746-1 as 350A, air-cooled, thread-on, brass. The same chart lists KP2746-2 as the corresponding 350A slip-on version, KP3076-1 as a 100A thread-on diffuser, and KP2747-1 as a 550A thread-on diffuser. The suffix and nozzle attachment style are functional, not cosmetic, differences.
The diffuser distributes shielding gas near the front of a MIG gun and provides the interface for compatible front-end components. It is part of an assembly: the neck, insulator, contact-tip design and nozzle all have to be correct together. A diffuser with a matching general description can still have the wrong thread, shoulder, seating surface or nozzle system. Use the exploded view associated with the gun’s exact model and revision.
Begin with the gun, not the diffuser
If the gun is marked Magnum PRO, that is a starting point rather than a conclusive parts match. Record the complete gun model, its part number, any production or connector variant, and the original front-end parts. Compare those identifiers with Lincoln’s current replacement-parts documentation. The “350A” diffuser designation is a product-family classification; it does not certify that every gun labeled 350A uses the KP2746-1.
Inspect the existing nozzle retention method without modifying or defeating the original assembly. If the nozzle threads onto its front-end holder, you may have a thread-on configuration; a slip-on nozzle uses a different attachment interface. The official guide explicitly separates thread-on KP2746-1 from slip-on KP2746-2. Do not select the one you happen to have on the shelf based solely on amperage.
Check the selling unit and exact part number
- Manufacturer: Lincoln Electric. Confirm packaging identifies a genuine Lincoln part where OEM is required.
- Part number: KP2746-1, not KP2746-2, KP2747-1 or KP3076-1.
- Type: 350A air-cooled brass diffuser with thread-on nozzle connection per Lincoln’s guide.
- Selling unit: the verified Arc Weld listing is one diffuser; a “-B25” suffix in the manufacturer guide describes bulk-pack numbering, not the single unit.
- Condition and kit scope: check whether seals, insulators or related components are sold separately before assuming a diffuser order constitutes a complete front-end rebuild.
The product’s advertised package is one each. If you are stocking an industrial maintenance bin, count individual gun stations and replacement cycles separately from how a supplier packages parts. A case quantity should never be silently inferred from the SKU or a photo of several diffusers. Verify current variant, pack quantity and inventory on the exact Arc Weld KP2746-1 listing.
Symptoms that justify inspection — not a blind diffuser replacement
Poor shielding gas coverage, irregular flow at the nozzle, an overheated contact-tip interface or visible front-end damage can lead a technician to inspect the diffuser. Those symptoms can also arise from an incorrect nozzle, a damaged neck, a blocked gas path, an improperly seated consumable, contaminated base metal or a shielding setup problem outside the gun. Replacing a diffuser without confirming the actual cause can leave the weld defect unchanged.
For example, porosity can have several causes. Check the entire system under the OEM troubleshooting procedure, qualified welding procedure and applicable shop controls: shielding-gas supply, connections, gas delivery, nozzle condition, work preparation and environmental exposure. A visible diffuser defect is relevant evidence, but it is not a substitute for an actual root-cause diagnosis. For broader gun issues see WSP’s Magnum PRO gun liner guide, which distinguishes mechanical wire-feed trouble from front-end consumable questions.
Match the front-end assembly before installation
Use the gun manufacturer’s service instructions for safe isolation and correct assembly. Confirm the gun is made safe from electrical and thermal hazards before any inspection. Compare the original components with the current parts drawing: diffuser, insulator, nozzle, tip, any applicable seal and the correct order of assembly. Do not force an apparently close thread fit, improvise seals or substitute a nozzle just because it threads partly onto a replacement.
The Lincoln chart identifies the O-ring replacement for 350A diffusers as KP3982-1. That is a separate part-number reference, not a claim that an O-ring is included with every KP2746-1 single-pack purchase. Check the existing design and current OEM instructions before determining whether a seal also needs ordering.
When to buy this exact part
Choose KP2746-1 when your actual Magnum PRO gun’s OEM parts breakdown identifies that number, the nozzle uses the proper thread-on front-end arrangement, and the required selling unit is one diffuser. Do not choose it merely because a listing says “Lincoln 350A diffuser,” because your current gun has gas-flow trouble, or because another brand offers a visually similar brass component.
If the removed component is missing or unidentifiable, pause the order and get the gun model/serial information, a photo of the full front-end assembly and the relevant diagram. This is more reliable than comparing worn threads by eye. WSP’s part identification resource provides a useful starting point when the existing part has no readable marking.
Short procurement checklist
- Confirm gun manufacturer, model, exact parts drawing and front-end revision.
- Verify KP2746-1 is listed, rather than KP2746-2 slip-on or an alternative capacity family.
- Check whether separate insulator, nozzle, contact tip or 350A O-ring KP3982-1 is also required according to the gun’s documented assembly.
- Confirm one-each selling unit, current online availability and the product’s current SKU before placing a maintenance order.
- Record the reason for replacement and use the original gun’s safety and troubleshooting guidance rather than assuming every gas issue is a diffuser failure.
A correct replacement prevents wasted purchasing and another teardown. The important choice is not between similar-looking brass pieces but between exact compatible front-end configurations. See the verified Lincoln KP2746-1 at Arc Weld once the OEM parts match is confirmed.
Sources: Lincoln Electric Magnum PRO Diffusers selection guide for model/type and related seals; Arc Weld exact active product and package for current commerce details, checked October 26, 2026.
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