Scraping is the process of creating various patterns on the surface of a workpiece after it has undergone fine shaving, finishing, or grinding. This technique is also referred to as embossing or picking. The operation typically involves using a fine scraper or a specialized knife to carve the desired design into the material.
There are numerous types of patterns used in scraping, including curved, square, wavy, and scalloped designs. Among these, curved patterns are particularly common and include styles such as the moon pattern and the swallow pattern.
**1. Basic Shaving Method for Curved Patterns**
To create a curved pattern, start by placing the scraper blade on the left side of the workpiece and then scrape diagonally from left to right (as shown in Figure 1a). During this motion, the left wrist should twist to guide the blade across the surface (as illustrated in Figure 1b). This movement shifts the cutting edge from the left to the right side, with the length of the cut generally around 10 mm. The entire process happens quickly, allowing for the creation of smooth curved shapes. The same method can be reversed, where the blade moves from right to left by adjusting the wrist movement accordingly.
The effectiveness of the curved pattern depends on several factors. First, selecting the right scraper is crucial—its width, thickness, cutting edge radius, and wedge angle all influence the final shape. Second, controlling the wrist's movement amplitude and the sliding stroke length plays a key role in achieving the desired curve. Lastly, utilizing the elasticity of the scraper head helps in shaping the pattern. Generally, a larger twisting motion results in a shorter push stroke and a smaller arc angle, producing a more compact curve, as shown in Figure 1c.
**2. Moon Pattern and Scraping Technique**
The moon pattern is depicted in Figure 2. Before starting, use a pencil to mark a square on the workpiece surface at a certain distance apart. When scraping, use an arc-blade fine scraper, positioning its center line at a 45-degree angle relative to the longitudinal centerline of the workpiece. Then, scrape from the front to the back of the piece.
**3. Swallow Pattern and Scraping Method**
The swallow pattern is illustrated in Figure 3a. Similar to the moon pattern, begin by drawing a square on the surface. Use the same arc-blade fine scraper, maintaining a 45-degree angle between the blade’s center line and the workpiece’s longitudinal axis. The basic approach involves first scraping a curved pattern, then slightly below it, forming a design that resembles a swallow, as seen in Figure 3b.
**4. Square Pattern and Scraping Technique**
The square pattern is shown in Figure 4. Begin by marking a square on the workpiece surface. Use a straight blade or a large-radius arc blade for short-stroke scraping. After completing the first square, leave a space equal to the square’s size before scraping the next one.
**5. Wave Pattern and Scraping Method**
The wave pattern is presented in Figure 5a. Before scraping, draw a square on the surface. Use a slit scraper, selecting the falling knife position (typically at the intersection point), and move the blade diagonally to the left. Once a certain length is reached, tilt it back to the right and push forward to start the next cut, as shown in Figure 5b.
**6. Scallop Pattern and Scraping Method**
The scalloped pattern is displayed in Figure 6a. Before scraping, draw a square and angle lines on the surface. A hook-and-blade scraper is used (as shown in Figure 6b). Sharpen the right end of the blade and keep the left end slightly dull, ensuring the blade remains straight. The technique involves selecting a falling knife position, holding the left hand about 50mm from the blade, pressing down on the left side, and rotating the blade clockwise (typically 90° to 135°) with the right hand. A properly executed fan-shaped pattern is shown in Figure 6c. Improper pressure may cause both ends to be scraped simultaneously, resulting in an uneven and shallow pattern, as seen in Figure 6d.
**7. Conclusion**
Scraping allows for the creation of attractive patterns on finished workpieces, enhancing their appearance. Additionally, it improves lubrication between moving parts and helps assess the wear of the surface based on the disappearance of the pattern. Whether for aesthetics, functionality, or maintenance, scraping is a valuable skill in precision machining.
125mm Wall Chaser Groove Cutting Machine
The 1700W 125mm Wall chasers are a twin bladed power tool which used to cut groove on brick, stone or concrete walls, perfect for electricians and plumbers, to lay wires or water pipes in the wall.
The 1700W 125mm Wall Groove Cutting Machine Chaser with Cutting Depth 0-28mm, cutting Width 14/19/29mm.
The Concrete Wall Cutting Machines With Spindle lock for easy blade change.
BTW, The Groove Wall Chaser Machine with Laser Function for cutting line straight.
The Wall Chaser work efficiency is much higher than the 5 blades wall chaser, and Less Dust with dust blower.
The 125mm Wall Cutting Machine is comfortable to use, due to anti-slip handle with soft grip cover.
The 1700 Brick Wall Chaser With Guide handle for easy work with little effort.
125Mm Wall Chaser Groove Cutting Mchine,Marble Cutter,Wall Cutter,Wall Chaser Grooving Cutting Machine
Ningbo Brace Power Tools Co., Ltd , https://www.cnbrace.com