Because the thickness gauge is very thin, you should pay special attention to it and be careful when handling it. If you don't pay attention, you will scratch the ruler. If several pieces are used together, the thinnest piece should be sandwiched. The gauge must be wiped clean before use.

The operation method of the seam on the table top (planar) is as shown in the right figure. First, insert a small piece of the front end of the ruler into the slit, hold the ruler cover with the left hand, and press the ruler with the right index finger (as close as possible to the workpiece). The friction of the piece (sometimes lined with fine gauze) is gently pushed forward (this method is mainly used for thin pieces below 0.10).

The operation method of the seam on the arc surface is as shown in the figure below, the same as above, but the ruler should be attached to the outer arc surface.

The operation of the seam on the vertical seam is as shown in the figure below. The left hand is provided with a ruler sleeve, and the right thumb and the second finger are held as far as possible to hold the ruler. The other three fingers are naturally gathered and gently tried to insert into the inside.