This method which is used to measure angle of V-grooves is also very suitable for measuring angle of profile and angle of machine-tool slides.
The discs used in this method should be of such diameter that y always touch sloping sides of groove only.

A precaution is needed when small taper is measured with help of balls. If ball is allowed to drop in hole, it will wedge taper of hole. Ball weight and measuring pressure that is exerted over it can cause appreciable axial movement and can give inaccurate readings.

In this method, after placing balls gap between balls is filled with combination of slip gauges. The length of slip gauges between balls should be noted very carefully.

The shape of tails and pins in dovetail joint is trapezoidal. A dovetail joint or simply is a joinery technique which is most commonly used in woodworking e.g. furniture, timber framing etc.

To check angle of tapered hole, balls of different size are used. This method is suitable for checking angle of a tapered ring gauge and very suitable for measuring relief clearance of dies.

In method of measuring angle of V-groove, First step is that small disc is placed in groove. After that height of smaller disc above surface plate is measured with help of height gauge.

Formula for finding angle of an internal dovetail is Tan A = (l₂-l₁/2) / h where l₁ and l₂ are distance across pins and h is height of slip gauges. Thus by knowing se three parameters, angle A can be calculated.

When internal taper of blind hole is measured by using balls n error in angle measurement of taper can be decreased by choosing height of slip gauge combination as large as possible.

Sin A/2 = (d₂-d₁)/2 ÷ (h₂-h₁)-((d₂-d₁)/2) is formula of angle of groove where A is angle of V-groove, d₂ and d₁ are diameters of discs and h₂ and h₁ are height of discs from surface plate.

In this method to check angle of tapered hole, balls are used. Smaller ball is of such size that it will be seated somewhere between hole that is not at bottom and not at top. Above it bigger ball will be placed.