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What is a limit thread gauge?

The limit thread gauge is a set of GO and NOGO. The GO can pass the thread under test smoothly, and the gauge must stop within 2 rotations (tooth) for this thread to be qualified.
Thread bolt gauge (also known as plug gauge, thread bolt gauge), thread bolt gauge is a gauge for checking female threads.
Thread ring gauge (also called ring gauge, ring tooth gauge), thread ring gauge is a gauge for checking male threads

The accuracy of ring gauges and bolt gauges must comply with "international standards" such as ISO, JIS, ANSI, DIN, BSI, etc. The accuracy test report is also attached. However, each brand has some "tolerance" in the specification. Therefore, it is recommended to use the "same brand" ring bolt gauge for testing with the corresponding manufacturer, which is less prone to tolerance disputes.

According to the requirements of different "workpiece types" and "tooth pitch", ring gauges and bolt gauges can be divided into:
M metric thread, UNC American thread coarse thread, UNF American thread fine thread, UNEF American thread extra fine thread, W inch thread,
Parallel threads for PF pipes, parallel threads for NPSM American pipes, pitch thread gauges for PT British pipes, pitch thread gauges for NPT American pipes,
BC bicycle etc.

Specification accuracy:
1. "ISO" metric standard: the commonly used grade of general bolt gauge is 6H, and the grade of ring tooth gauge is 6g
2. "JIS" new standard: the commonly used grade of general bolt gauge is 6H, and the grade of ring tooth gauge is 6g.
3. "JIS" old standard (divided into work and inspection): grades are divided into grades 1, 2 and 3 (commonly used grades are grade 2).
4. "ANSI" American standard: The grade classification is the same as the new JIS, but the tolerance range is different (not mixed).
American teeth: (UNC, UNF, UNEF, UNS, UN)
1. "JIS" old system standard: bolt thread gauge grades are 3B, 2B, 1B; ring thread gauge grades are 3A, 2A, 1A.
2. "ANSI" American standard: the grade is the same as the Japanese standard, but there is no difference between work and inspection, and the tolerance range is also different.

JIS is a Japanese standard. According to the purpose of use, thread gauges are divided into two types for work and inspection, while ISO standards have no such distinction.
According to the purpose of use, the Japanese JIS standards can be divided into: GP-IP (inspection regulations), GP-WP (working regulations), and GP-NP (ISO standards).

Example: outer diameter 3mm, pitch 0.5mm

  Outer diameter gap Pass end Stop Precision
ISO M3 x0.5 GP NP 6H
What is a needle gauge?

Necessary inspection tool for needle gauge to measure precision holes

Needle gauges, also known as plug gauges, bolt gauges, pin gauges, cylindrical gauges, PIN gauges and PIN GAUGE, etc., are gauges designed to check whether products meet standards. They are made of stainless steel, tool steel, ceramics, tungsten steel, and bearing steel. A round rod with a specific size made of high hardness and other materials. It is used to check the position, measure the size of the hole, check the distance between two holes, and can also be used as a stop gauge and measure the depth of the hole. It is a necessary inspection tool for standardized inspection of holes.

The precision specifications of the needle gauge are as shown in (below):

The outer diameter of the needle gauge size ranges from φ0.200 to φ50.00m, and the standard product is below φ20mm, and can be produced to three decimal places. 0.2mm~10.00mm, the accuracy of the general standard pin gauge is ±0.5um, and the accuracy of the ultra-precision type is ±0.3um (applicable to high-precision industries such as optical fiber).

Types and classification of needle gauges

EISEN needle gauge materials are divided into three categories

  1. Bearing steel
  2. ceramics
  3. Super hard (tungsten steel)
Needle gauge introduction Steel standard product Ceramic standards Super hard standard

φ0.05~φ1.499mm SKH-51 tool steel

φ1.50mm~SUJ-2 bearing steel (high carbon steel)

φ0.2~20.00mm ceramic

φ0.10~φ0.30mm ultra-fine super-hard alloy

φ0.30~ V-20mm tungsten steel

Abrasion resistance general good excellent
Rustiness general excellent good
Temperature effect general good excellent

Our company is the general agent of EISEN, a major Japanese manufacturer, in Taiwan. The needle gauges sold are all made in Japan and imported with original packaging. EISEN is a world-renowned manufacturer of gages such as bolt ring gauges and diamond knives. Few listed and OTC companies are their users.

What types of metal hardness testers can be subdivided into?

Hardness testers are roughly divided into metal hardness testers, rubber (plastic) hardness testers, gem hardness testers, cement hardness testers, etc. Generally speaking, most of what we discuss are metal hardness testers and rubber hardness testers.

The types of metal hardness testers can be subdivided into

  • Rockwell Hardness Tester
  • Micro Vickers Hardness Tester (Micro Vickers Hardness Tester)
  • Vickers Hardness Tester
  • Brinell Hardness Tester
  • Leeb Hardness Tester

Rubber (plastic) hardness testers are generally distinguished by English characters, such as A type, D type, C type, F type, etc., which are roughly divided into rubber, plastic, foam, etc., such as Teclock, Kori, etc. There is a Barcol Hardness Tester that can also detect plastics, aluminum products, PE and leather.

Then explain the general purpose of the metal hardness tester:

Rockwell hardness

Common test rulers are HRC, HRB, HRA, HRE and HR15N, HR30N, HR15T, HR30T, etc. In fact, Rockwell hardness testing machine can also measure plastic products whose rulers are HRR, HRL, HRM, such as detecting the hardness of substrates. HRC hardness scales are generally used to detect the hardness of hard metals and heat-treated steels, HRA are generally used to detect the hardness of tungsten steel, and HRB are used to detect the hardness of soft metals or untreated steel. As for HRE, the general inspection is aluminum products. As for HR15N and HR30N, the surface hardness is tested. HR15T and HR30T detect the hardness of thin iron or tinplate.
It is widely used for metal hardness testing of various metal parts, molds, heat treatments, etc. It can be tested immediately and quickly for checking material strength, incoming material inspection, and metal hardening energy test.

Micro Hardness Tester/Micro Vickers Hardness Tester (HMV)

The detection range is very wide, ranging from soft metals to hard metals. It can also detect the hardness of coatings, glass and ceramics. The ruler is displayed as HV. There is also a Knoop Hardness Tester (Knoop Hardness Tester), and the ruler is displayed as HK. The use load is 10g to 1kg. As for the Vickers hardness gauge, the ruler is HV, but the load is 1kg to 50kg. At present, many specifications use 10kg to beat the hardness of the material.

Vickers/Vickers Hardness Tester (HV)

It is suitable for measuring thin materials and small metal materials. The measurement range can cover almost all metals. According to the characteristics of the test, the hardness value of the material obtained after the force of the same material is similar, and the test High precision, compared with Rockwell hardness method, it is suitable for hardness testing with a wide range of changes.

Leeb Hardness Tester (HL)

It is widely used in the hardness test of large materials, special structures such as pressure vessels such as elevators and boilers, metal warehouse materials, molds, aerospace, transportation, offshore wind power and other permanent assembly components. It is not only convenient to carry, but also can use different shapes Impactor, to meet different test requirements, and can maintain stable testing in harsh environments.

Brinell hardness tester

The large load force used in the detection, the large diameter of the probe, the large indentation diameter, are suitable for the hardness testing of large-grain metal materials, such as cast iron, forging materials, non-ferrous metals and their alloys, various annealing, quenched and tempered metals, and For steel materials, for softer metals such as pure aluminum, copper, lead, zinc, tin, etc. and their alloys, the test accuracy is stable and accurate.

How to choose the best hardness test method?

The hardness test you choose should be determined based on the microstructure (such as uniformity) of the material you are testing, the type of material, the size of the part and its condition.