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Abrasive Grit Size: How To Choose the Right Coarseness
The right abrasive makes a huge difference on your finished projects. Whether tackling massive pieces or small, delicate parts, you need abrasive tools with the right level of coarseness to create a smooth, refined finish. Brush up on the basics of abrasive grit size with this guide on how to choose the right coarseness for your metalworking project.
Defining Grit Size
Before you can choose the right sandpaper or grinder for your project, you need to make sure you understand what you’re looking for. Metalworkers classify sandpaper and other abrasives by grit size. This refers to the number of sharp particles per square inch of the sandpaper. A higher grit size means there is a greater density of particles, which creates a smoother finish.
Coarse Abrasives
When you have tough jobs that require subtle shaping or stripping outer coatings, coarse abrasives are the way to go. Extra coarse abrasives refer to sandpaper and other abrasives with a grit size of 24- to 36-grit. This low grit size is extremely tough and is only useful for jobs that require you to remove tough outer coatings.
You can also use coarse abrasives, which have a grit size range of 40- to 60-grit. These are good for removing previous finishes or roughly shaping the surface of the piece.
Medium Abrasives
Medium abrasives fall between 60- and 120-grit. These abrasives work well to smooth the surface of the piece. You can also use medium abrasives to remove small imperfections such as scratches or planning marks from your piece.
Fine Abrasives
Fine and extra-fine abrasives give your piece a super smooth, even finish. Fine grit sizes range from 120- to 220-grit. However, many intricate parts and products you make in your machine shop will require an extra-fine finish, which ranges anywhere from 240- to 600-grit depending on your project. Extra-fine abrasives are ideal for creating an ultra-smooth surface to apply finishes or other coatings. Additionally, 600-grit abrasives are useful for polishing pieces.
Other Factors To Look For
Grit size isn’t the only thing to look for in your abrasives. In addition to choosing the right coarseness and abrasive grit size, you also want to pay attention to material quality. The higher the quality of your grit material, bonding agent, and backing, the better your finish will be. You also need to choose between open-coated and closed-coated abrasives. Open-coated sandpaper features gaps between grits to collect shavings and other particles as you work, while closed-coated sandpaper does not.
Finding the right abrasive for your project doesn’t have to be complicated. Explore a comprehensive selection of grinding abrasives and other abrasive tools at TMT Toolbox. Our extensive inventory and expert service makes it easy to find the perfect tools for your next project.