Champion Big-Lock Threaded Adapter and Reducer (73mm to 220mm)

Two Big-Lock parts, two different jobs, and they are easy to confuse at the counter.

• A threaded adapter takes a grooved Big-Lock connection to an NPT thread. This is how an aluminum main lands on a receiver, a dryer, a compressor discharge, a valve or an existing steel header.
• A reducer steps the main from one Big-Lock size down to the next. Both ends are grooved tube connections.

One thing to get right before you order: the reducers are supplied WITHOUT couplings. Every reducer needs two straight union couplings, one for each end, ordered separately. The elbows and tees elsewhere in the Big-Lock range include theirs; the reducers do not. This is the most common short order on the range.

Choose your fitting from the dropdown above.

Model Selection Chart

Threaded adapters, grooved to NPT

Champion catalogs threaded adapters in 73mm, 90mm and 115mm only. Above 115mm, a main is normally taken to a flanged connection with a Big-Lock flange kit rather than a thread, which is also what most equipment that size expects.

Reducers, tube to tube, couplings NOT included

The range has gaps: there is no catalogued 168mm to 73mm, 220mm to 73mm or 220mm to 90mm reducer. Those steps are made with two reducers in series, or more sensibly with a reduction tee. Ask us if you are trying to drop more than one size at once.

Reduce Only Where the Demand Drops

Reducing a main is a decision about flow, not about tidiness. Diameter is the single biggest lever on pressure drop, and every step down costs you capacity for the whole length of pipe that follows it.

Reduce where a genuine chunk of demand has already been taken off, typically after a major branch. Do not reduce simply because the far end of the building is quieter; on a loop main, air reaches the far end from both directions and the diameter should stay constant the whole way round. If you are unsure, send us the layout and we will tell you whether the step is costing you anything.

Shared Technical Specifications

Specification note. Champion's price list publishes description, part number and list price for the Big-Lock range and nothing else: no pressure rating, no temperature band, no weights and no dimensions, and we have not found a Big-Lock datasheet that supplies them. This listing states only what Champion publishes. Ask us and we will source anything further from the factory before you order.

Ideal Applications

Landing a Big-Lock main on a compressor discharge, a receiver tank, a refrigerated or desiccant dryer, a large filter housing or an isolation valve; tying new aluminum into an existing threaded steel header during a phased retrofit; and stepping a plant main down after a major branch has been taken off.

Building a Complete Big-Lock System

• Big-Lock aluminum pipe, 73mm to 273mm
• Straight union couplings - two per reducer, plus one per tube joint
• 90 and 45 degree elbows and street elbows, couplings included
• Junction tees and reduction tees, couplings included
• Plug caps
• Air dryers and compressed air filtration, which is usually what the threaded adapter is landing on

Ordering Notes

• All Big-Lock products and accessories are NO CANCEL / NO RETURN, per Champion's current price list.
• Freight: freight collect from Huntersville, NC 28078 or Las Vegas, NV 89113.
• Shipping weights: Champion publishes no weight for any Big-Lock fitting, so no catalog weight is carried on these variants.
• Photography: Champion publishes no photograph of the Big-Lock adapters or reducers, so this listing is deliberately shown without an image rather than with a stand-in from another manufacturer's grooved range.

Why Buy from Air Compressor Store

Air Compressor Store is an authorized Champion Pneumatic distributor. The adapters are where a new aluminum system meets whatever is already in the building, and that is exactly the interface that gets mis-specified. Send us photos of the connections you have to land on and we will tell you which adapters and couplings the job needs.

Frequently Asked Questions

Do reducers really not come with couplings?

Correct, and it catches people out. Reducers are the only fitting in this part of the Big-Lock range supplied bare. Order two couplings per reducer. Elbows and tees end WC for with couplings; the reducer part numbers do not.

Why is the 73mm x 2-1/2 in male adapter only $52 when the 1-1/2 in and 2 in are both $113?

That is what Champion's August 2026 price list publishes, and it is a sharp enough outlier that we have queried it with the factory. We list it at the book price. If you are ordering a quantity of these, tell us and we will have the price confirmed in writing first.

Why is the 115mm x 4 in male adapter cheaper than the 3 in?

$151 against $158, which is what the book prints. Another inversion we have flagged. Both are listed as printed.

Male or female thread?

Match what you are landing on. A male adapter goes into a female port such as a receiver boss or a valve. A female adapter accepts a male thread. Champion catalogs female adapters in only three places, 73mm x 2-1/2 in, 90mm x 3 in and 115mm x 4 in, all at the full line size.

Can I adapt a 168mm or 220mm main to a thread?

Not with a catalogued threaded adapter; they stop at 115mm. Use a Big-Lock flange kit to a mating flange, which is the normal approach at that size, or reduce to 115mm first and then adapt. Ask us which is cleaner for your connection.

Do I need thread sealant?

On the NPT side, yes, PTFE tape or a liquid sealant rated for compressed air. The grooved side seals mechanically on the gasket and needs nothing.