Before using an angle grinder, fit the guard, wear safety glasses plus a face shield, hold it firmly with both hands, and never mount a wood saw blade to cut wood

Cost

Safety glasses plus a face shield cost a few dozen CNY. Each time before starting, take a look at the guard and the disc, and unplug it before changing the disc, which takes a minute or two. The hard part is not removing the guard or working one-handed when you find it a nuisance.

What you get

Practices listed by the Canadian Centre for Occupational Health and Safety and a workplace safety agency in Queensland, Australia, are as follows. Before starting, check the guard and the disc, and don't use one with cracks, chips or deformation. The maximum speed marked on the disc must not be lower than the speed marked on the machine. The disc's diameter and center hole must fit the machine. Disconnect the power before changing the disc. Clamp down whatever you will grind or cut first. Wear safety glasses or goggles, with a face shield over them. Hold both handles with both hands and stand firmly. A cutting disc must not be used for grinding, since that makes it more likely to break. Don't set the machine down until the disc has fully stopped. Direct sparks and debris toward where no one is, and keep flammable things away. A Queensland notice says the edge of a cutting disc is designed for about 70 meters per second. Putting a 356 mm disc on a 230 mm machine takes the edge speed to at least 120 meters per second, and the disc easily breaks. In February 2016 a local worker using a 230 mm angle grinder was hit in the chest by fragments and died of internal injuries. There are two accident investigation reports in China. In 2019 in Harbin a worker swapped the cutting disc for a toothed saw blade and, with no guard fitted, went to cut a board. The blade caught his trousers, cut his thigh artery, and he died of blood loss. In 2024 in Futian, Shenzhen, a worker used an angle grinder fitted with a wood saw blade and with no guard or auxiliary handle to cut a wooden door frame. The machine kicked back, cut his carotid artery, and he died. The national standard cited in the report says “do not attach a saw chain, wood-carving blade or toothed saw blade.” In South Korea's emergency-room injury surveillance from 2011 to 2018, 8697 visits were for injuries from high-speed rotating cutting tools, of which 4603 were with grinders of this kind. 46.4% were hurt on the hand and 23.0% on the head. Compared with other similar tools, grinder injuries were about twice as likely to be serious (OR 2.07, 95% CI 1.88–2.29). A hospital in Mianyang, Sichuan, treated 36 inpatients with grinder eye injuries over two years. After surgery, 10 still had a best vision below 0.05. At one hospital in Turkey, of 742 acute hand and forearm injuries in a year, angle grinders caused 82. Apart from 8, none happened on the job, and 44% were retired people. At a trauma center in Japan, of 15 grinder injuries in 2017 to 2018, 9 were misuse such as fitting a saw blade to cut wood. Of these, 2 people lost whole fingers and 1 lost part of one (Canada, Australia / China / South Korea, Turkey, Japan).

Notes

Why grade C: these practices come from safety agencies' guidance and accident investigations, and no study has calculated how many injuries following them would prevent. The injury data show only how severe injuries are, and each is a case series from one hospital or one country. The size of benefit is set at medium based on judgment: the consequences can be death, blindness or lost fingers, but they fall only on the person using the grinder. The manual of the Harbin machine itself said not to fit toothed saw blades and that the guard must be fitted. The worker had a hand saw at hand, and for cutting wood you should use a woodworking tool like that. Loose clothing, dangling jewelry and long hair should all be tied back, since they can get pulled in. Dust and noise are heavy while grinding; for the details on masks and earplugs, see §19.10 (the employer must provide protective equipment). If a large blood vessel is cut, press hard on the wound first; see §13.12 (for heavy bleeding, press hard on the wound first). The beneficiary is mainly you, and also family members standing by to help.

Evidence grade

C : The author's experience or common practice, without direct literature.

Sources

1. Canadian Centre for Occupational Health and Safety (2025). Abrasive Wheels - Use of Portable Grinders. https://www.ccohs.ca/oshanswers/safety_haz/abrasive_wheels/safeuse1.html
2. Canadian Centre for Occupational Health and Safety (2025). Powered Hand Tools - Use of Grinder Attachments. https://www.ccohs.ca/oshanswers/safety_haz/power_tools/powered-hand-tools-use-of-grinder-attachments.html
3. Workplace Health and Safety Queensland (2017). Guards and discs on angle grinders. https://www.worksafe.qld.gov.au/news-and-events/alerts/workplace-health-and-safety-alerts/2017/guards-and-discs-on-angle-grinders
4. 哈尔滨市松北区人民政府 (2019). 哈尔滨三发装卸运输有限公司「8.28」机械伤害事故调查报告. https://www.songbei.gov.cn/hebsbq/tzgg/201910/c01_797872.shtml
5. 福田区人民政府沙头新洲南村房屋装修工程「3·14」一般机械伤害事故调查组 (2024). 沙头新洲南村房屋装修工程「3·14」一般机械伤害事故调查报告（引 GB 3883.3-2007 第 8.12.1.102 条 a、e 项）. https://www.szft.gov.cn/attachment/1/1507/1507749/11317197.pdf
6. Song J, Jeon YB, Jang JH, Cho JS, Choi JY, Choi WS. (2023). Severity of grinder injuries and related factors compared with other high-rotation cutting tool injuries: a multicenter retrospective study from 2011 to 2018. Journal of Trauma and Injury, 36(1), 32-38. https://doi.org/10.20408/jti.2021.0057
7. Ke W, Gu K, Zhu S, Wu J, Dai Y. (2025). Prognostics Factors to Avoid Eye Injuries in Angle Grinders. Journal of Craniofacial Surgery, 36(6), e629-e631. https://doi.org/10.1097/scs.0000000000011108
8. Sozbilen MC, Dastan AE, Gunay H, Kucuk L. (2018). A prospective study of angle grinder injuries in the hands and forearms during a one-year period. Hand Surgery and Rehabilitation, 37(5), 300-304. https://doi.org/10.1016/j.hansur.2018.07.002
9. Tsumura T, Matsumoto T, Matsushita M, Kishimoto K, Shiode H. (2021). Do Not Cut Wood with an Angle Grinder, or You Might Lose a Finger: A Retrospective Study. Journal of Hand Surgery Asian-Pacific Volume. https://doi.org/10.1142/s2424835521500053

Translated from the Chinese original. Original book, section 1, tip 42. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer