Lincoln Viking 3350 Hard Hat Adapter Guide: Run Your Hood Under a Hard Hat

← All Posts helmets Weld Gear Team Last updated on July 19, 2026

Work on a jobsite that requires a hard hat and you hit a problem fast: your Lincoln Viking 3350 headgear and a hard hat both want to live on your head, and they will not share. The answer is a hard hat adapter, a kit that lets the Viking shell mount to a slotted hard hat so you get overhead protection and your auto-darkening hood together. This Lincoln Viking 3350 hard hat adapter guide covers which kit to buy, the slotted-versus-non-slotted trap, and how to set it up.

The Two Adapter Types

The most important thing to understand before ordering is that there are two versions, because there are two kinds of hard hats:

Slotted hard hat adapter, Lincoln KP3486-1. This is for the common cap-style hard hats that have accessory slots on the sides (the standard slots that also accept earmuffs and face shields). Most jobsite hard hats are slotted.
Non-slotted / Halo-style adapter, Lincoln KP3047-1. This is for hard hats without accessory slots, using a strap-around mounting.[^https://www.amazon.com/dp/B0BQXFKGSQ?tag=mysuggestions01-20]

Both fit the Viking auto-darkening family, including the 1740, 1840, 2450, and 3350. Buying the wrong style for your hard hat is the number one adapter mistake, so check your hard hat for accessory slots before you order.

What Comes in the Kit and How It Works

A Viking hard hat adapter kit replaces the standard headgear mounting with brackets that clip into the hard hat’s slots (or strap around a non-slotted shell). The Viking shell then pivots on those brackets the same way it would on the normal headgear, flipping up and down as you work. You keep the hard hat’s own suspension for head protection, and the welding shell rides in front of it.

How to Install It

Remove the standard headgear. Take the normal Viking headgear off the shell by releasing the side pivots and rear mount.
Attach the adapter brackets to the hard hat. For the slotted KP3486-1, slide the brackets into the hard hat’s accessory slots until they click. For the non-slotted KP3047-1, fit the strap mount around the hard hat shell.
Mount the shell to the brackets. Attach the Viking shell’s side pivots to the adapter brackets, the same pivot points the headgear used.
Set pivot tension and distance. Adjust the tension so the hood flips up and stays down, and set how far the lens sits from your face.
Check clearance. Flip the hood down and confirm the lens seats correctly and the hard hat brim does not foul the shell.

The Honest Trade-Offs

Two things to accept going in. First, a hard-hat-mounted setup sits farther from your face and higher up than the standard headgear, so the lens is a bit more distant and the whole rig feels bulkier and more front-heavy. That is the price of stacking two pieces of PPE, and it is universal to hard hat adapters, not a Lincoln flaw. Second, comfort over a long day is worse than the standard headgear, because you are carrying the hard hat plus the hood. Use the adapter when the jobsite requires a hard hat, not by choice.

Who should skip it: shop welders with no hard hat requirement, who are far more comfortable running the standard Viking headgear.

The Bottom Line

A Lincoln Viking 3350 hard hat adapter lets you stay compliant on a hard-hat jobsite without giving up the 3350’s excellent lens: choose the slotted KP3486-1 for standard slotted hard hats or the non-slotted KP3047-1 for shells without slots, both fitting the 1740 through 3350. Accept that the setup rides farther out and heavier than normal headgear, install it slots-first, and check your clearance. Match the adapter to your hard hat rather than guessing, and one head can finally wear both the protection the site demands and the hood you actually like.

Frequently Asked Questions

What hard hat adapter fits the Lincoln Viking 3350? There are two: the slotted adapter KP3486-1 for hard hats with accessory slots, and the non-slotted Halo-style adapter KP3047-1 for hard hats without slots. Both fit the Viking 1740, 1840, 2450, and 3350.

How do I know if I need the slotted or non-slotted adapter? Check your hard hat. If it has accessory slots on the sides (the ones that accept earmuffs and face shields), use the slotted KP3486-1. If it has no slots, use the non-slotted KP3047-1.

Does the hard hat adapter fit other Viking models? Yes. Both adapters fit the Viking auto-darkening family, including the 1740, 1840, 2450, and 3350.

Do I keep the hard hat’s suspension? Yes. The adapter mounts the welding shell to the hard hat while you keep the hard hat’s own suspension for head protection.

Does a hard hat adapter change how the helmet feels? Yes. The lens sits farther from your face and higher up, and the combined rig is heavier and more front-heavy than the standard headgear. That is normal for any hard hat adapter.

Can I still flip the hood up with the adapter? Yes. The shell pivots on the adapter brackets just like it does on the standard headgear, so it flips up and down and you can set the tension.

Should I use a hard hat adapter in the shop? Only if a hard hat is required. For shop work with no hard hat rule, the standard Viking headgear is more comfortable.