Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Introduction The sine bar is the most accurate instrument for measuring angles. It consists of a accurate straight rectangular bar made of high quality steel and having two accurately lapped cylindrical plugs or rollers at the ends. The rollers are so fixed that when sine bar is placed on surface plate, the surface of the bar is exactly parallel to surface plate. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Types Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Principle of Working of Sine Bar: By placing the slip gauges under the one roller, the bar surface can be made parallel to any angular surface of work. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Measuring known angles For this purpose the surface plate is assumed to be having a perfectly flat surface, so that its surface could be treated as horizontal. One of the cylinders or rollers of sine bar is placed on the surface plate and other roller is placed on the slip gauges of height h. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH https://www.youtube.com/watch?v=F7uCEeipdCw Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Measurement of Angle for Small Component: For checking the angle of small size components, a sine bar is set up approximate (Nominal) angle on a surface plate by suitable combination of slip gauges. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Measurement of Angle for Large Component: When component is too large to be mounted on the sin-bar, the sine bar can be mounted on the component. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Sine Bars Used on surface plates and any angle by raising one end of bar with gage blocks Made 5 in. or in multiples of 5 in. Lapped cylinders with 5 in. ±.0002 or 10 in. ± .00025 between centers Face accurate to within .00005 in. in 5 inches Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Activity Run to the Board Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Sine Bars Hypotenuse of a right-angle triangle Gage block buildup forms side opposite Face of surface plate forms side adjacent Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Example Calculate the gage block buildup required to set a 5 in. sine bar to an angle of 30º buildup = 5 (sin 30º) = 5(.5000) = 2.5000 in. Note: This formula applied only to angles up to 60º . Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Sine Bars Angles > 60º Better to set up work using complement of angle Angle plate turned 90º to produce correct angle When sine bar in near-horizontal position, small change in height of buildup will produce smaller change in angle than near-vertical position Small angles Sometimes impossible to get buildup small enough to place under one end of sine bar Place gage blocks under both rolls of sine bar Net difference in measurement equal to required buildup Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Sine Centre Conical workpiece difficult to mount so Sine centre is used. Centre can be adjusted. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH

Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH Sine Table One roller of the sine bar is hinged on its datum surface It can be sung at any angle from 0 to 90 degree. Measuring Angles of Taper Plug Gauge. Unit-2 , M&M, Sine Bar , B SUSILA AP/MECH