What does a no go thread gauge check?

Asked By: Alvydas Woude | Last Updated: 6th June, 2020
Category: automotive auto parts
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A go/no-go gauge refers to an inspection tool used to check a workpiece against its allowed tolerances via a go/no-go test. Its name is derived from two tests: the check involves the workpiece having to pass one test (go) and fail the other (no-go). ISO 1502 sets a standard for threads and gauging to test them.

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In respect to this, how many turns can a no go thread plug gauge?

three complete turns

Subsequently, question is, what is difference between GO gauge and no go gauge? To inspect hole size of a part, the Go gage is inserted into the hole. If the gage can be entered into the hole, then the hole is considered to be above its low limit. Following that, the No Go gauge is used: if it enters the hole, than the hole is too big.

Secondly, what does a thread gauge check?

A solid thread ring gauge is used to check acceptance of a “screw” – i.e. externally threaded part. The GO and NO-GO rings are normally separate pieces. A thread ring gauge is designed to check the correctness of the thread, to include thread depth and pitch diameter (to the given pitch / TPI).

What is 6g tolerance?

The 5g indicates the tolerance class for the pitch diameter and 6g is the tolerance class for the major diameter. A fit between threaded parts is indicated by the nut thread tolerance designation followed by the bolt thread tolerance designation separated by a slash.

34 Related Question Answers Found

What is a thread plug gage?

A thread plug gage is designed to check the pitch diameter (to the given pitch / Threads per inch). In order for the part to pass inspection and be accepted, the GO gage should pass through the entire length of the nut, without requiring the use of too much rotational force.

What does 6h mean on a thread?

The 6H is the tolerance position and designates the tolerance/fit to be used when machining the thread.

What is the difference between 6g and 6h threads?

It is based on ISO 1502. The basic profile of the ISO threads is shown below. BS 3643 Pt1 and Pt2: 2007 specifies the fundamental deviations and tolerances for e.g. 5H, 6H, 6G and 7H for internal threads, and 4H, 6g, 6e, 8g for external threads.

ISO Metric Theads.
GO 6H 0 338
NOGO 6H 0 339
GO 6g 1108
NOGO 6g 1109
Knife Any 2144

How is thread depth measured?

Generally thread depths are designed to be measured from the center line of the first full thread in the bottom of the threaded hole. This means that the gage must also be manufactured to measure from the same location. The depth notch on the go thread plug gage is usually ground 90 degrees to the axis of the gage.

How do you find the pitch diameter of a thread?


The three wire method is used to measure pitch diameters using conventional, flat anvil micrometer screw gauges. This process involves placing three wires (one wire on one side of the thread with the other two wires on the opposite side) of known diameter within the pitch of the threads.

What gauge is used to check internal threads?

A thread gauge, also known as a screw gauge or pitch gauge, is used to measure the pitch or lead of a screw thread. Thread pitch gauges are used as a reference tool in determining the pitch of a thread that is on a screw or in a tapped hole.

How do I check my NPT threads?

To gage Internal N.P.T. taper pipe threads, screw the N.P.T. thread plug firmly into the product – do not force. The thread is within the permissible tolerance when the gaging notch of the plug is not more than one turn plus or minus from being flush with the end of the product.

Do I need both go and no go gauges?

No, you don't need both. You only need the GO gauge. Gordy Gritters uses a single piece of scotch tape on the back of the go gauge. That makes the gauge .

How do you use NPT thread gauge?

To gage Internal N.P.T. taper pipe threads, screw the N.P.T. thread plug firmly into the product – do not force. The thread is within the permissible tolerance when the gaging notch of the plug is not more than one turn plus or minus from being flush with the end of the product.

How do you calibrate thread gauges?


Calibration Procedures for Thread Ring Gages
  1. Select the corresponding master set plug.
  2. Clean and inspect ring gages for nicks and embedded metal filings and burrs.
  3. Turn the ring gage locking screw counter-clockwise until it is loosened.
  4. Turn the adjusting screw clock-wise which opens the ring to a larger pitch diameter than the setting plug.

What is a go no go feeler gauge?

The Go NoGo feeler gauge works by incorporating a design which differentiates between a thinner tip and a thicker body. The tip is able to 'Go' into the space and the thicker body stops 'NoGo'. Each leaf has an upper and lower value, typically 0.002″ (0.05mm) apart.

How do you use a 6 step NPT gauge?

Screw the L1 plug into the fitting (hand tighten). This classifies the thread as to “Maximum”, “Basic”, or “Minimum”. Insert 6-step Crest Check plug into the fitting. When the L1 plug is at the maxi- mum notch, the 6-step gage must go between “MX” and “MXT” notch.

What is go no go decision?

go/no-go decision. Determination to proceed with or abandon a plan or project. In quality control, 'go' denotes that a product conforms to the specifications; when it does not, it is 'no go. '

What is gage tolerance?

Gage tolerance is the gage's increments of measure (also called resolution or discrimination). Your process tolerance is the allowed deviation from a target value that keeps product purpose (process variation). For example, your company manufactures ball point pens with a ball outer diameter of 0.35 mm.

What is the purpose of ring gauge?


A ring gauge, or ring gage, is a cylindrical ring of a thermally stable material, often steel, whose inside diameter is finished to gauge tolerance and is used for checking the external diameter of a cylindrical object.

How many types of gauges are there?

All gauges can be divided into four main types, independent of their actual use.

What is Gauge and types?

Plug Gauges : These are used for checking holes of many different shapes and sizes. Ring Gauges : External diameter measuring gauges. Taper Gauges : Taper testing gauges. Snap Gauges : These are used for checking shafts. Thread Gauges : These are used for pitch diameter of the thread.