ねじ用限界ゲージの種類と使い方＜ねじゲージ＞ | オーエスジー

The use of screw gauges is determined by JIS standards.

Use the accuracy grade of the drawing instruction and inspect the screws according to the prescribed method.

[Limit gauge for screws types and how to use them]

Name Shape	Plug gauge		Ring gauge
use	For internal thread		For external thread
	GO	Stoppage	GO	Stoppage
Current JIS 6H, 6g, etc.	GP	NP	GR	NR
Conventional JIS Grade 1~3	GP	WP (Machining)	GR	WR (Machining)
		IP (for inspection)		IR (for inspection)
use JIS B0251	When screwed in by hand without applying excessive force You have to go through GO → overall length Stopping side (current JIS) → Passes if it is not screwed in more than 2 revolutions Stopping side (conventional JIS) → Pass if you do not enter more than 2 rotations

In the conventional JIS and the current JIS (ISO), not only the accuracy of the screw has changed, but also the symbol of the gauge has also changed.
The GO of the plug gauge is now and has always been GP, but the stop side of the current JIS is NP,
Conventionally, JIS stops are divided into two types: WP for machining and IP for inspection.
The same is true for ring gauges, where GO is GR.
On the stopping side, there are NR of the current JIS and WR/IR of the conventional JIS.

GO What is a screw plug gauge?
This is a external thread -shaped gauge that inspects the total effective diameter of a internal thread .
If you pass through, it will pass in that the effective diameter is not too small,
Thread accuracy is guaranteed by inspecting and passing the set with the stop screw plug gauge.
In addition to the effective diameter, the tolerance of the half-width of the mountain and the tolerance of the pitch are also determined.

What is a stop side screw plug gauge?
A external thread -shaped gauge that inspects the effective diameter of a internal thread .
If it stops within the regulations, it passes in that the effective diameter is not too large.
Thread accuracy is guaranteed by inspecting and passing the test as a set with the thread screw plug gauge.
If there is a distinction between machining and inspection, machining is mainly used in the manufacturing department and at the shipping source.
Inspection is mainly used in inspection departments and shipping destinations.

GO What is a thread ring gauge?
This is a internal thread -shaped gauge that examines the total effective diameter of external thread .
If you pass through, it will pass in that the effective diameter is not too large,
Thread accuracy is guaranteed by inspecting and passing the set with the stop screw ring gauge.
In addition to the effective diameter, the tolerance of the half-width of the mountain and the tolerance of the pitch are also determined.

What is a fast-side screw ring gauge?
A internal thread -shaped gauge that inspects the effective diameter of a external thread .
If it stops within the regulations, it passes in that the effective diameter is not too small.
Thread accuracy is guaranteed by inspecting and passing the thread as a set with the thread ring gauge.
If there is a distinction between machining and inspection, machining is mainly used in the manufacturing department and at the shipping source.
Inspection is mainly used in inspection departments and shipping destinations.

* How to use the gauge
There is a slight difference between the current JIS and the conventional JIS in terms of the passing conditions on the stopping side.
When screwed by hand without excessive force,
GO must go through overall length .

・ISO (current JIS)
The current JIS stop side, which determines the pass/fail of 6H ( internal thread accuracy) and 6g ( external thread accuracy) thread accuracy, is
If it is not screwed in more than 2 turns, it will pass

・Conventional JIS
The conventional JIS stop side, which determines the pass/fail of the thread accuracy of grade 1 and grade 2, passes if it does not enter more than 2 rotations.

If you read exactly, when it was just 2 turns,
It passes the current JIS and fails the conventional JIS.
However, depending on the feelings of the user, it is just two revolutions that will be doubtful
I think that it is a source of trouble to consider it as a pass.
A good screw that is properly made to the hole entrance and tip often does not fit a single turn.
For screws that hold a stop gauge for nearly two turns, it is a good idea to check the machining status, including the tool.

・Limit gauge
The limit method used in the term limit screw gauge is:
It is to check the minimum and maximum to prove that it is within the specified tolerances.
The thread limit gauge verifies that the effective diameter of the screw is within the tolerance.
In addition, there is also a gauge called a plug gauge that does not have a screw.
This inspects whether the hole diameter is within the tolerance.