Description
Product Overview
The SK 2.00–2.50mm AA-Grade Gauge Pin Set gives you 51 precision ground steel pins in 0.01mm steps — the exact increment resolution you need when qualifying bores, setting plug gauges, checking reamer sizing, or dialling in fine clearance fits right at the lower end of the metric pin range. This is a toolroom-grade set built to AA/2A accuracy standards, meaning each pin is ground and lapped to within ±0.001mm of its nominal — the kind of traceable reference you can actually trust when a bore tolerance is ±0.005mm and you’ve got one shot at the fit.
- AA/2A Accuracy Class — ±0.001mm tolerance per pin: The difference between an A-grade and AA-grade pin set is real when you’re checking a 2.10mm bore on a Swiss-type lathe or verifying the go/no-go status of a reamed hole. AA class means each pin is ground to within a micron of nominal — not just “close enough” but traceable reference quality suitable for inspection and production use.
- 0.01mm incremental steps across 2.00–2.50mm: Fine-step coverage across this range lets you walk a pin through a bore to find the actual size, not just confirm go/no-go. That’s the difference between knowing your bore is 2.24mm and only knowing it passed a 2.20mm pin. Useful for identifying tool wear progression or dialling in reamer geometry incrementally.
- Knurled steel handles with engraved size markings: Each pin is fitted with a knurled grip body with the size etched into the top face — readable at a glance on the bench without needing to squint at a label. The handles also provide consistent grip force, reducing the risk of cocking the pin in the bore and getting a false reading.
- Organised in a labelled plastic holder inside a timber case: The foam-lined timber box with individual labelled slots is not a luxury — it’s a calibration management tool. Pins stored correctly stay undamaged, and slots make it immediately obvious when one is missing. The original SK case is included with this set.
- Ideal for: Checking small bore diameters on Swiss-type lathes and CNC turning centres, qualifying reamed holes in jig plates, verifying punch and die clearances, setting adjustable bore gauges, and inspecting small EDM-machined cavities where a dial bore gauge won’t reach.
Condition
Used (Good Condition / Partial Seal, 2 Pins Missing)
This is a used set in genuinely good working condition, with a transparent caveat: two pins are missing — 2.21mm and 2.49mm — and buyers should factor that into their application before purchasing. Of the remaining pins, a number are still sealed in their original factory plastic bags, unused and in factory-fresh condition. The used pins have been stored correctly — coated in protective oil and housed in the closed plastic holder inside the timber case — which is exactly how you want precision gauge pins stored. There is no sign of abuse, corrosion, or handling damage reported on the working surfaces. At this size range, a pin with a raised burr, a rust pit, or a rolled edge is useless; oiled, handled pins that seat cleanly in the holder suggest the set has been used by someone who understood what they had.
The absence of 2.21mm and 2.49mm is a real limitation if your work demands full sequential coverage across the range — for example, walking a pin set through a bore to find the exact size. If your application only requires spot-checking specific nominal sizes, or if you’re setting adjustable gauges at known points, the gap may be entirely irrelevant. Replacement individual SK pins can often be sourced separately if required. As with any used gauge pin set, we recommend verifying individual pin diameters against a calibrated reference — either a high-resolution micrometer with a calibrated anvil and spindle, or a benchtop comparator zeroed to a certified ring — before relying on the set for critical inspection work.Included:
- 1 x SK 2.00–2.50mm AA/2A Gauge Pin Set (49 of 51 pins present — 2.21mm and 2.49mm missing)
- 1 x Original SK labelled plastic pin holder
- 1 x Original timber storage case with foam-lined lid
- Remaining factory-sealed pins in original plastic bags
Not included:
- 2.21mm gauge pin (missing)
- 2.49mm gauge pin (missing)
- Calibration certificate
Brand Information
SK (Shinwa Sokutei / SK Japan) is a well-regarded Japanese precision measuring instrument manufacturer with a long history supplying the toolroom and inspection market across Asia-Pacific and beyond. SK tools sit in the same tier as RSK and Niigata Seiki — a step below Mitutoyo and Mahr in price, but manufactured to genuine Japanese quality standards with consistent ground surfaces and proper hardened tool steel. For gauge pins specifically, Japanese manufacture is a meaningful quality indicator: the precision grinding and lapping culture in Japanese metrology manufacturing is reflected in dimensional consistency that holds up in production use, not just on the first check out of the box.
Specifications
| Feature | Specification |
|---|---|
| Brand | SK (Shinwa Sokutei, Japan) |
| Product Title | SK 2.00–2.50mm Gauge Pin Set AA-2A |
| Type | Cylindrical Gauge Pin Set |
| Accuracy Grade | AA / 2A — ±0.001mm per pin |
| Measuring Range | 2.00mm – 2.50mm |
| Graduation / Step Increment | 0.01mm |
| Total Pins in Full Set | 51 |
| Pins Present | 49 (2.21mm and 2.49mm missing) |
| Pin Handle Type | Knurled steel handle with engraved size marking |
| Material | Hardened and ground tool steel |
| Country of Origin | Japan |
| Condition | Used (Good Condition) — mix of used (oiled, stored) and factory-sealed pins; 2 pins missing |
| Included Items | 49 gauge pins, original SK labelled plastic holder, original timber case with foam lid |
| Not Included | 2.21mm pin, 2.49mm pin, calibration certificate |
Keywords
SK gauge pin set, SK 2.00-2.50mm pin set, AA grade gauge pins metric, precision gauge pin set Australia, small bore inspection pins, toolroom gauge pins, plug gauge pins metric, gauge pin set 0.01mm steps, cylindrical gauge pins machinist, bore checking pins CNC, Japanese gauge pins, metric pin gauge set inspection
