American Thread Identification Kit | Includes: Thread Pitch Gauge, Fitting Identification Cards, Vinyl Bag for identifying NPT, JIC, ORFS, O-Ring Boss, NPSM, and SAE 45
Find out what an unmarked fitting is
This kit identifies six common U.S. hydraulic fitting standards: NPT, NPSM, JIC, SAE 45°, ORFS, and O-Ring Boss. Match the part to a card, find its size, then confirm the thread and seat angle with the gauge.
It works on male and female ends and packs into one vinyl bag for the service truck or the bench.
How to identify a fitting
1Match the shape
Compare the end of the fitting to the drawings and pick the card that matches. If it has a flare or cone seat, hold it against the angle gauges on the tool to confirm the angle.
2Find the size
Test the part against the sizes on that card until you find the closest fit. The chart on the card gives you the dash size and nominal size.
3Confirm the thread
Set the pitch gauge in the threads. When the teeth sit flush with no light showing between them, read the TPI and check it against the card's chart.
Male outside diameter
Female inside diameter
Inside or outside threads
The six standards on the cards
Where a fitting seals is often the fastest way to narrow it down.
| Standard | Thread | Seals on |
|---|---|---|
| NPT | Tapered pipe | The threads |
| NPSM | Straight pipe | 30° seat (60° included) in the female swivel |
| JIC | Straight UN/UNF | 37° flare |
| SAE 45° | Straight UN/UNF | 45° flare |
| ORFS | Straight UN | O-ring in the flat face |
| O-Ring Boss | Straight UN/UNF | O-ring at the base of the male thread |
Fittings that are easy to mix up
Some of these standards share a thread, so a thread count alone won't settle it. Check these instead.
JIC or SAE 45°?
Several dash sizes use the same thread. Check the flare instead: JIC is 37° and SAE is 45°, and the gauge has a guide for each.
NPT or NPSM?
They share threads per inch and are close in diameter. NPT threads taper and seal on the threads. NPSM threads run straight, and the swivel seals on a 30° seat.
JIC or O-Ring Boss?
Male ends share the same UN/UNF thread sizes. A JIC male has a 37° flare on the nose. An ORB male has an O-ring at the base of the thread instead.
What's in the bag
Six identification cards
One card per standard. Each has a chart of dash size, nominal size, and threads per inch for every size on the card.
Angle and thread pitch gauge
Reads 11, 11.5, 12, 14, 16, 18, 19, 20, 24, 27, and 28 TPI, plus 1.0, 1.5, and 2.0 mm metric pitch, on inside or outside threads.
Angle gauges for 37°, 45°, 30° (60° included), and 12° (24° included) seats. Also sold separately.
Blue vinyl bag
Holds the cards and gauge together so nothing goes missing between jobs.
Working on British or metric equipment?
The cards cover U.S. standards only. The gauge reads metric pitch, but to identify BSPP, BSPT, JIS, DIN, Komatsu, or Kobelco fittings, use the TGK-01 BSP and metric thread gauge kit.
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