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Checking workpieces for accuracy
Published in David Salmon, Penny Powdrill, Mechanical Engineering Level 2 NVQ, 2012
Workshop protractors are instruments used for setting and measuring angles. They can be read to an accuracy of about ±1/2° (±30 minutes). Workshop protractors are usually supplied as part of a combination set. The components that make up a combination set are: hardened steel rule (usually 300 mm)moving protractor head that incorporates a spirit levelsquare head with 45° edge and a spirit levelcentre head.
Marking out and measuring
Published in Andrew Livesey, Alan Robinson, The Repair of Vehicle Bodies, 2018
When the edge of the workpiece forms an angle which deviates from the usual angles of 90° and 45°, this angle may be determined with the aid of an adjustable protractor. The protractor consists of a semi-circular segment covering 180°. The movable blade which indicates the angle reading is secured by a locknut which can be set and tightened at any angle, thus allowing angles to be read directly from the workpiece. Such a protractor may also be used for marking out when the marking lines do not form one of the usual angles.
Analysis of drilling behavior of flax/PP composites
Published in Materials and Manufacturing Processes, 2023
Deepak Kaushik, Inderdeep Singh
Three standard twist drill bits (Make: Miranda) of point angle 118° were purchased. The point angle of the drill bits was then changed using a tool point grinder to fabricate the TW135 and TW90 drill bits. Point angle measurement was performed using protractor and later validated with the help of Image J software. Hollow drill bits (TP and US type) were designed and fabricated to reduce the TF and delamination. The trepanning tool used in this study has two cutting edges as shown in Table 3. Diameter of all drill bits was maintained at 6 mm as per ASTM standard for bolted joints in polymer matrix composites. Wall thickness of hollow drill bits was kept as 1 mm, and the inner diameter was 4 mm. Table 3 represents the geometry of the drill tools used for conducting the experiments.
Introducing the concept of angle to young children in a dynamic geometry environment
Published in International Journal of Mathematical Education in Science and Technology, 2020
Some researchers have studied the implementation of a variety of technological tools such as graphing calculators TI-73 (Browning & Garza-Kling, 2009), Kinect for Windows program (Smith, King, & Hoyte, 2014), dynamic geometry systems such as LOGO activities (Simmons & Cope, 1990; Clements & Burns, 2000), Sketchpad (Kaur & Sinclair, 2012) and mobile learning using Sketchpad Explorer (Crompton, 2015) as an alternative method for promoting children’s understanding of angles. Crompton (2015) worked with fourth-grade students interacting with a real-world environment while using mobile technology with Sketchpad Explorer program to support their learning. In her study, students interacted with the real world by taking photographs of physical objects in the environment and then using dynamic tools such as protractor within the program to measure the angles. Crompton (2015) reported about students’ moving to higher van Hiele levels of geometric understanding after the teaching experiment. The present study is different from Crompton’s study in the sense that it does not focus on the standard measurement using dynamic protractor and classification of angles; rather it focuses on promoting and developing the interpretation of angle as a turn using dynamic sketches in Sketchpad.
Surface parameters measurement of braided preform based on local edge extreme
Published in The Journal of The Textile Institute, 2019
Zhitao Xiao, Lei Pei, Fang Zhang, Ying Sun, Lei Geng, Jun Wu, Jun Tong, Jia Wen
For comparison, the pitch lengths are also measured manually by clicking the corner points of image FL on the computer screen. As illustrated in Figure 12(a), from the coordinates A(131, 283) and B(129, 377) we can calculate the pitch length as dM = dAB × dP, where and dp is true distance per pixel according to image calibration. dM is measured ten times and the average value is chosen as one pitch length. Manual measurements of the surface braiding angle by protractor are demonstrated in Figure 12(b). Angle θ is measured to be 69.35° and thus the surface braiding angle θM is set to θM = θ/2 = 69.35/2≈34.68°. θM is also measured ten times and the average value is chosen as one surface braiding angle.