Introduction
Shaping, smoothing, and removing material from surfaces all heavily rely on grinding discs. Fundamental in their way, grinding discs come in many different grit sizes. They can help you attain the appearance that you want. A comprehensive guide shows you how to choose the correct grinding disc for each project.
Understanding Grit Size
The size of the grains refers to the grade of coarseness or fineness of these grains to be present in a grinding wheel. It is denoted by a number, where lower numbers represent coarser grades and higher numbers represent finer grades of grains. Thus, a 36-grit wheel is much coarser than a 120-grit wheel
The Grit Size Spectrum
The size of a grinding disc’s individual grits can vary from as few as 16 to well over 600. The standard for all grinding discs is that every individual abrasive on the disc must always stay exactly the same dimension after it’s used for just one wheel turn. However, the next common part of the specification is grit size. Usually, the grit sizes on disc labels range in groupings of ten (10) from 16 through 600. Yet, some 6-1/8-in.-dia. discs I recently purchased specified “600 & Beyond” on the packaging.
Factors Influencing Grit Selection
- There are several factors to consider when choosing the right grit size. One of the most important is the type of material being worked with. You must match up the coarseness or fineness of the abrasive particles to the hardness or softness of the work material. For example, the fabulous Mr. Ron Covell, an expert in metal fabrication, says you should employ rougher (20- to 60-grit) abrasives to work on steel, and use finer (80- to 120-grit) abrasives on softer metals like aluminum (of which we have a fine example in our ’64 Valiant art car, “Dodge by Chuck.”)
- Another factor affecting grit-size choice is the desired finish. The old “start rough and finish fine” method still works on many projects (Figure 3)
General Guidelines
While there are no hard and fast rules, here are some general guidelines for grit selection:
- Rough Grinding: 36-60 grit
- General Purpose Grinding: 60-80 grit
- Blending and Smoothing: 80-120 grit
- Finishing: 120-220 grit
- Polishing: 240+ grit
Tips for Choosing the Right Grit
Follow the manufacturer’s advice. Look for the information right on the package of the grinding disc or find it on the manufacturer’s website. They’ll tell you what to use for the specific task you’re doing. If you don’t get that guidance, start with a coarse grit and move to a medium, then fine grit to complete the job. You could even use extra fine grit for really smooth finishes. If you want to be perfect on the safety front, take the advice of the Arffman engineer and use those dust-collecting systems they feature on job sites. They might be a good thing to ask for if you’re renting a grinder instead of working in your home shop with your “outdoor” dust collection system.
Conclusion
It is important to select the appropriate grain size when choosing a grinding wheel. The grain size affects both the efficiency and the finish of the grinding process. The tool life and safety of the grinding wheel are also affected by the grain size. Since the grain size of a grinding wheel cannot be changed, it pays to be careful when selecting the right grain size. The type of work the grinding wheel will be used for and the material density of the workpiece largely determine the grain size.
Credit to: UDO is the distributor of NKK grinding discs and cutting discs, which are products that emphasize quality. and low costs for technicians and industrial manufacturers in various fields who need to use it Find information about grinding work and additional product information at: www.udo.co.th/category_product/ใบตัดใบเจียร
