Please ask the old fitter master to tell me about the scraping and grinding of the bearing bush.

Scraping is divided into rough scraping and fine scraping. Coarse scraping should be combined with the machining allowance, and the scraping speed of the bearing gap is faster.； The scraping blade should be "light", "accurate" and "quick" in precision scraping (grinding points), "removing the solid and leaving the virtual" while taking into account the contact angle. This requires many years of practical experience to achieve.

Please let me know how to do fine scraping, Master.

When scraping finely, use a dummy shaft to apply red elixir and grind the spots repeatedly to remove the high spots. After repeated contact, the area will naturally increase.

The scraping process of horizontally split bearing bush (1) Coarse scraping of bearing bush. As shown in Figure 5 a Figure 5 Scraping of the split sliding bearing (bearing bush) a Lightly scrape the machining knife marks on the upper and lower bushes. It is required that all the tile surfaces should be scraped, the scraping should be even, and the processing marks should be scraped off. b. Paint the color on the shaft, scrape it roughly with the upper and lower tiles several times, then insert the upper and lower tiles into the tile base and cover respectively. Paint the tiles, scrape them roughly with the grinding point of the shaft. After the contact area and grinding points are evenly distributed, you can switch to fine scraping. When rough scraping, you should be careful not to scrape off the tile mouth. Full contact within 180° is required. (2) Scrape the bearing bush carefully. As shown in Figure 5b. When scraping the bearing bushes finely, the upper and lower bushes should be padded (the joint surface of the bearing bushes). After assembly, the bearing bushes at both ends are scraped, painted on the bushes, and ground with a shaft. When starting to press and assemble, the pressing force should be uniform, and the shaft should not be pressed too tightly, as long as it can rotate. Remove the pad as you scrape it, and tighten it as you go. At this time, you should also be careful not to scratch the tile mouth. After repeated scraping, the spots on the tile contact surface will be evenly distributed and dense. (3) Precisely scrape the bearing bush. As shown in Figure 5c. The purpose of fine scraping is to scrape the contact spots and contact area to meet the requirements specified in the drawing. The grinding method is the same as rough scraping. The spots are from large to small, from deep to shallow, from sparse to dense. During the scraping process, large spots can be broken with a scraper to become dense small spots. After multiple scrapings, the scraping will gradually reach the requirements. At the end of the fine scraping, it is very important to scrape out the lubricating oil wedge (opening hole) and side clearance so that they can reach the performance of the bearing bush. When scraping the bearing bush, the condition of the shaft-related parts, such as the center distance deviation, the contact condition of the step wheel tooth surface, etc., should be considered at the same time during rough scraping and fine scraping, so as to ensure the accurate position of the shaft. Small accumulated errors caused by machining can be further eliminated by scraping. Larger errors cannot be solved by scraping.

I just don’t understand the rough hanging at the end. I usually hang the side gaps first, and then scrape the 60° contact area underneath.

Follow the WeChat public account and there is an open class on tile scraping given by Wang Zhen.