Ground Joint Hammer Lock Air Hose Fittings, 2 in and 3 in, Couplings, Unions and Clamps
Ground joint fittings, also called hammer lock or hammer union fittings, are the heavy duty way to terminate large bore air hose. The joint seals metal to metal on a ground seat and is tightened with a hammer wrench rather than by hand, which is why it holds up on 2 in and 3 in bull hose running rock drills, blast pots and jackhammers where a lighter coupling would not survive a week.
This listing covers the complete couplings, the unions and the clamps that go with them.
What each part is
- S1282 (GJ200F): 2 in complete coupling, hose barb x 2 in female NPT
- S1283 (GJ300F): 3 in complete coupling, hose barb x 3 in female NPT
- S1284 (GDS200): 2 in full union, both halves
- S1285 (GMS200): 2 in union half x 2 in male NPT
- S1286 (4BC200): 2 in four bolt hose clamp
- S1287 (4BC300): 3 in four bolt hose clamp
How the pieces fit together
The complete coupling is what you put on the end of a hose: the barb goes into the hose, the clamp goes over the outside of the hose to hold it on, and the ground joint end is what mates to the next piece. Order a clamp with every barbed end, because the barb on its own will not hold under pressure.
The full union joins two lines together. The union half with a male NPT is for landing a hose on a pipe, a manifold or a piece of equipment that already has a female port.
Fitting it
Use a hammer wrench on the lugs, which is what they are there for; a pipe wrench on a ground joint chews the lugs and the next person cannot undo it. Make sure the ground seat is clean before you close the joint, because a bit of grit on the seat is the whole reason a ground joint leaks. Check the clamp bolts after the first pressurisation and again after a day of use, as hose relaxes around the barb.
Safety
These fittings have no shutoff. Bleed the line down fully before you break a joint, and fit anti whip safety cables across every coupled joint on large bore air hose. A 2 in hose that separates under pressure is a serious injury, and the cable is the cheapest part in the whole assembly.
Related parts
We also stock 2 in and 3 in black close nipples for joining ground joint fittings to pipe, plus air hose, anti whip safety cables and twist lock hose couplings for smaller lines.
Not sure which one
Tell us the hose ID and what you are connecting it to, and the Warthog Air Compressor Store team will put the right combination together before you order.
Ground joint hammer lock air hose fittings in 2 in and 3 in: complete barb couplings, full unions, male NPT union halves and four bolt hose clamps.
NOTE: Actual product may be different from pictured!
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