精度表記stdとは | オーエスジー

Accuracy notation STD is the accuracy of the tap recommended when machining thread accuracy grade 2 or 6H female thread equivalent. The accuracy notation STD indicates how much tolerance the effective diameter of the tap is controlled. It is an abbreviation for Standard. STD+1, STD+2, etc. are called oversizes.

As the number of STD+1, STD+2, and so on increases, the tolerance position of the tap effective diameter increases. How large the tolerance position varies depending on the type of tap and the pitch. For cutting taps, it is +20 μm for every STD+1 at a pitch greater than or equal to 0.7. The pitch is +15 μm with a pitch of 0.6 or less. For rolled taps, it is +12.7 μm for every STD+1, regardless of pitch.

The tap accuracy STD is set so that it is easy to aim for passing the thread accuracy grade 2 and 6H gauge for each application and size, such as taps for general use and taps for SUS. Therefore, even with the same thread size, the tap accuracy may vary depending on the type of tap.

・ Cutting tap accuracy OH accuracy

・ Rolling tap accuracy RH accuracy

・ Is there a tap that can be processed with a thread accuracy of 6H?