Stone knowledge: Stone cylinders

Types of ordinary cylinders
The ordinary cylinder introduced here mainly refers to a cylinder with a straight or curved generatrix, but a circular cross-section of equal or unequal cross-section, such as an equal diameter cylinder, a conical cylinder, a drum shaped cylinder with a diameter less than the middle diameter at both ends, and a railing column.
Roman pillar
Generally, it refers to a special-shaped cylinder with several grooves machined in the direction of the generatrix on the outer surface of the cylinder. From the cross-section of the Roman column, its circumference is composed of equal sized straight segments and concave circular segments, connected by equal intervals. The grooves on Roman columns are generally not continuous near the base and cap of the column. According to the different heights of the columns, Roman columns can be a whole column made of stone, or a column formed by splicing several sections of the column with the column base and cap.

The diameter and height of an ordinary cylinder mainly depend on the size of the waste material, with a minimum diameter of 100mm and a maximum diameter of 2000mm or less; Whether it is a whole or a part of a cylinder, its individual height is generally less than 5000mm, but there are also some special cylinders with a height exceeding 5000mm. A standard stone column includes three parts: a column base, a column body, and a column cap.

Processing process of cylinders
Stone columns refer to solid or hollow core columns used for architectural decoration made of marble and granite. They can be divided into marble columns and granite columns according to the type of stone used; According to the external characteristics of the columns, they can be further divided into Roman columns, plum blossom columns, twisted pattern columns, railing columns, carved columns, multi prism columns, as well as monochromatic columns and polychromatic columns; According to cross-sectional dimensions, it can also be divided into equal diameter columns with equal cross-section, conical columns with unequal cross-section, and drum columns. The difference from the circular arc plate is that the circular arc plate is only used to wrap the decorative column and is a part of the outer surface of the column; A stone column is a solid or hollow solid or spliced cylinder.

（1） Grinding and Polishing of Cylinders
The grinding and polishing of a cylinder is generally carried out on a lathe equipped with a pneumatic or hydraulic pressure grinding head. The abrasive installed on the grinding head can be quickly replaced. The abrasive used for grinding and polishing the cylinder is usually a circular ring type, using a line grinding and polishing method with the end face in contact with the cylinder. Ruyi Daliomac Company’s cylindrical machining lathe grinds and polishes cylinders.
Due to the fact that the grinding force during grinding and polishing is much smaller than the cutting resistance during forming and cutting, when clamping the grinding and polishing cylinder, only the center hole support can be used at one end of the headstock.
The grading of grinding abrasives varies depending on the material of the polished stone. When processing granite, 5 different types of abrasives with different thicknesses can be used, and when processing marble, abrasives can be used.
Due to the large fluctuations in the contour lines of railing posts, vases, and other products, it is difficult to grind and polish them using the above-mentioned circular abrasive ring. Therefore, simple grinding and polishing equipment for manually grinding irregular rotating bodies is still used to complete the polishing process of railing posts and other products.

（2） End face trimming processing
After the polishing process of the cylinder is completed, a diamond saw blade can be used to cut the two end faces of the cylinder to meet the requirements of the finished product size. It must be noted that the angle between the cut end face and its axis should be slightly less than 90 degrees, so that the joint can be small and beautiful during installation.
（3） Cleaning, Inspection, and Packaging
The processed cylinder can be packaged after cleaning, inspection, and drying. The packaging of the cylinder is divided into two steps. Firstly, the cylinder is sealed with a plastic film with a thickness of 0.5mm, and then fixed in a wooden fence. During packaging and transportation, attention must be paid to preventing collisions with the cylinders.

The processing steps for Roman columns are even more complex
Roman column groove processing
The cutting tool for processing Roman column grooves generally uses a milling cutter disc with embedded diamond blocks. The cutting section of the diamond blocks is in the shape of an arc, in order to machine grooves with curved sections. The width of the clump determines the width of the groove, so when machining Roman columns with large diameters, the milling cutter head is similar to a diamond roller.

There are also techniques for processing twisted grain columns, solid column foundations, and column caps
There is also a type of irregularly shaped cylinder similar to the Roman column, which is called a plum blossom column in China. The circumference of its cross-section is formed by evenly dividing and connecting convex circular curved segments. This type of plum blossom cylinder can be machined using a milling cutter disc with concave diamond blocks embedded and welded, and the equipment requirements are the same as when machining Roman columns. Roman columns are generally decorated with matte or chiseled or burned surfaces. When decorating with matte finish, the glossiness of the outer surface can reach the level after diamond cutting. If it is necessary to polish the surface of a Roman column, the cylindrical part of its outer surface should be polished at most because polishing in the groove is difficult. If you need a bright groove surface, you have to use a soft grinding disc for manual polishing.

A seemingly simple cylinder
Behind it, there are so many processing steps hidden
Containing the immortal spirit and exquisite craftsmanship of stone craftsmen

Case study of stone cylinders