Polski 
- 98% satisfied customers
- 72h delivery
- 30 dni na zwrot
Description
THREAD1 1/8"-12 UNF
TOLERANCE2A
STANDARDASME B1.1
MATERIALTool steel
Thread ring gauge UNF 1.1/8-12—where this thread is used
Limit gauging per ASME B1.2
| TECHNICAL DATA | |
|---|---|
| Thread type | Unified inch fine thread UNF |
| Thread size | 1.1/8-12 |
| Threads per inch | 12 TPI |
| Thread pitch | 2.117 mm |
| Nominal diameter | 28.575 mm |
| Tolerance class | 2A |
| Pitch diameter d2 | 27.003 – 27.155 mm |
| Gauge type | Set: GO ring + NO-GO ring |
| Material | Tool steel, hardened |
| Hardness | 58-62 HRC |
| Standard | ASME B1.1 / ASME B1.2 |
| Manufacturer | Varel |
T
GO ring gauge — screwed on by hand along the full bolt thread.
Z
NO-GO ring with a groove in the knurled surface — stops after no more than 3 turns.
The 1 1/8-12 UNF-2A engraving on the face of both ring gauges indicates the size and tolerance class of the bolt being inspected.
UNF 1.1/8-12 thread ring gauge checks an external thread—on a bolt, fitting end, or stud. The GO ring gauge must thread on by hand over the full thread length; the NO-GO ring gauge must advance no more than three full turns per ASME B1.2.
One and one-eighth inches belongs to the twelve-thread-per-inch family, in which ASME B1.1 specifies the same pitch for five consecutive diameters. This particular size is the least common in the family: hydraulic systems skip it, and cylinder catalogs more often list the neighboring sizes—1 1/4 and 1 3/8 inches.
Identifying the thread before measurement
Caliper, thread pitch gauge, and thread gauge
The entire family from one inch to one and a half inches has identical pitches 2.117 mm and differs only in diameter. A thread pitch gauge will give the same result for all five sizes. Measurement distinguishes them: 25.400 mm is one inch, 28.575 mm is 1 1/8, and 31.750 mm is 1 1/4.
The pitch is derived from the designation: 12 threads per inch means 25.4 divided by 12, or 2.117 mm. The basic pitch diameter is 28.575 − 0.6495 × 2.117 = 27.200 mm. Class 2A ring gauges check it within the range 27.003 – 27.155 mm, below the basic value by an allowance of 0.046 mm.
Classes 1A, 2A, and 3A—size 1.1/8-12
Which class to use for each application
Comparison of external thread classes
The basic pitch diameter for this thread is 27.200 mm. Classes 1A and 2A have an allowance of 0.046 mm, so their upper limit lies below the basic value. Class 3A has no allowance.
| Class | Allowance [mm] | d2 permissible [mm] | Tolerance zone | Application | Status |
|---|---|---|---|---|---|
| 1A | 0.046 | 26.927 – 27.155 mm | 0.229 mm | Field assembly, threads exposed to impact damage | |
| 2A | 0.046 | 27.003 – 27.155 mm | 0.152 mm | Commercial standard — bolts and threaded studs | THIS PRODUCT |
| 3A | 0.000 | 27.087 – 27.201 mm | 0.114 mm | Aviation, precision engineering |
Class 2A is the commercial standard — it covers the vast majority of inch bolts and mates with class 1B, 2B, and 3B internal threads. Class 3A is used where tightening torque must be repeatable from part to part.
GO/NO-GO inspection of external threads
Three steps per ASME B1.2
1
The GO ring gauge is threaded by hand, without force, over the full thread of the 1 1/8-12 UNF bolt.
2
The NO-GO ring stops after no more than 3 full turns, without forcing.
3
The GO ring passed and the NO-GO ring stopped — the bolt meets class 2A.
Thread inspection in 3 steps
1 GO ring (GO gauge)
Screwed on by hand — passes over the full length
2 NO-GO ring (NO-GO gauge)
Screwed on by hand — no more than 3 full turns
✓ Acceptable thread
Class 2A confirmed
At a pitch of 2.117 mm, the three permissible turns of the NO-GO ring gauge equal 6.351 mm. For a short thread, the limit must be reduced.
GO ring (GO gauge)
Represents the maximum material condition—27.155 mm. It must pass over the full thread length without resistance; resistance indicates an oversized thread or a damaged thread form.
NO-GO ring (NO-GO gauge)
Represents the minimum material condition—27.003 mm. It may advance up to three full turns, which equals 6.351 mm at this pitch. The body may be stamped LO.
✓ Thread acceptable — GO screws onto the full thread, NO-GO stops.
✗ Thread oversized — GO does not screw onto the bolt.
✗ Thread undersized — the NO-GO ring screws on more than 3 turns.
▲
Do not confuse it with the hydraulic 1 1/16-12 thread
In ORB O-ring ports, dash -12 uses the thread 1 1/16-12, or 26.988 mm—not 1 1/8 inches. The difference of one-sixteenth of an inch is 1.588 mm, enough to prevent the fitting from screwing in. When identifying a thread in a hydraulic body, measure the diameter before selecting a gauge.
Inspection scope and storage
What the gauge confirms and what it cannot measure
INCLUDED IN THE SET:
| ▸ | GO (pass) ring gauge UNF 1.1/8-12 2A |
| ▸ | NO-GO (reject) ring gauge UNF 1.1/8-12 2A |
| ▸ | NO-GO ring marked with a groove or dot |
WHAT IT CANNOT MEASURE:
| ▸ | Thread major diameter — for 2A, this is 28.240 – 28.529 mm |
| ▸ | Stud straightness and runout |
| ▸ | Thread flank roughness |
Frequently asked questions
No. In ORB ports, dash -12 has a 1 1/16-12 thread, or 26.988 mm, not 1 1/8 inches. These two sizes differ by one-sixteenth of an inch and have the same pitch, so they are easy to confuse. Measure the diameter with a caliper before selecting a gauge.
Only by diameter, because all have the same pitch of 2.117 mm. A caliper measurement distinguishes them: 25.400 mm is one inch, 28.575 mm is 1 1/8, 31.750 mm is 1 1/4, 34.925 mm is 1 3/8, and 38.100 mm is 1 1/2 inches.
No. The GO ring gauge will detect an oversized thread, but it will also screw onto an undersized thread. Only the NO-GO ring gauge checks the other limit of the tolerance zone. Inspection with a single ring gauge is the most common mistake in external thread acceptance inspection.
No. Ring gauges assess pitch diameter and thread form. The major diameter is checked with a separate plain gauge—the permissible range for class 2A in this size is given in the section on inspection scope.
Product accessories
Reviews
No customer reviews for the moment.
Shipping
All orders are delivered by courier company GLS. For orders exceeding 369 PLN gross shipping is FREE
| Courier GLS | Przelew24 / Prepayment | 14,76 zł gross | Delivery time 1 working day |
| Courier GLS | Cash on delivery | 17,26 zł gross | Lead time 1 working day |
Recommended for you
This website uses its own and third-party cookies to improve our services and show you advertising related to your preferences by analyzing your browsing habits. To give your consent to its use, press the Accept button.
Cookie preferences
Functional cookiesTechnical
Functional cookies are strictly necessary to provide the services of the shop, as well as for its proper functioning, so it is not possible to refuse their use. They allow the user to browse through our website and use the different options or services that exist on it.
Advertising Cookies
These are cookies that collect information about the advertisements shown to users of the website. They can be anonymous, if they only collect information about the advertising spaces shown without identifying the user, or personalised, if they collect personal information about the user of the shop by a third party, for the personalisation of these advertising spaces.
Analytics cookies
Collect information about the user's browsing experience in the shop, usually anonymously, although sometimes they also allow the user to be uniquely and unequivocally identified in order to obtain reports on the user's interests in the products or services offered by the shop.