OH accuracy means that in order to satisfy a predetermined internal thread accuracy, the accuracy of the tap can be selected according to the working conditions.

This is OSG's unique tap accuracy method, in which the accuracy of the tap is set in a step-type manner.

When determining the accuracy of a internal thread , the pitch diameter of the tap is one of the most important quality characteristics.

Normally, the standard level of tap accuracy is class 2 specified by JIS, but tapped internal thread does not always have the same accuracy as the grade of tapping.

This is because the finished dimensions of the internal thread change depending on the sharpness of the tap, the material used, and other factors.

For this reason, OSG has adopted a unique OH accuracy method that allows you to set the cutting tap accuracy in stages and select it according to the work situation.

It is aimed at machining with the OH precision tap and machining the screw within the thread accuracy of the drawing instructions, depending on how much the pitch diameter of each is used.

internal thread Accuracy and tap accuracy e.g. M10X1.5

(1) Pitch diameter (2) Reference pitch diameter (3) JIS tap accuracy (4) OH tap accuracy (5) Pre-JIS internal thread accuracy (6) JIS internal thread accuracy