that increase the accuracy of these estimates are the vernier scale and the micrometer The term least count is applied to the smallest value that can be read. The least count of metre scale is 1mm and that of the ammeter shown below is 2 ampere Vernier callipers, an instrument for making very accurate linear. function as expected. 2. What is VERNIER. (a) A caliper gage with a vernier. (b) A Vernier, reading + is LEAST Count of the Vernier caliper.
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material and many things from research papers to e-books can be found in PDF format. Secondly the least count is used to calculate the vernier caliper readings using a precise formula which is pretty useful and accurate. Vernier caliper least counts formula is calculated by dividing the smallest reading of the main scale with the total number of divisions of the. Least count = 1 main scale division - 1 vernier scale division Now, we know 10 divisions in main scale = 1cm 1 division in main scale(1 MSD).
Posted by: admin in Mechanics April 26, 0 19, Views Vernier caliper least counts formula is calculated by dividing the smallest reading of the main scale with the total number of divisions of the vernier scale. LC of vernier caliper is the difference between one smallest reading of the main scale and one smallest reading of vernier scale which is 0. Vernier caliper is an instrument used to measure the length, diameter, radius etc.
It is used by the lathe mechanic for making metallic cylinders of different sizes. There are two scales of V. C Vernier scale Main scale The main scale is graduated is centimeter while Vernier scale slides along the main scale and is graduated in division less than the millimeter. The thickness or external diameter of an object. The jaws A and B are fixed where B and D are movable.
The movable jaws are attached to the vernier and they slide along the main scale. Read also : Micrometer screw gauge least count The smallest reading which can be accurately measured with a vernier caliper is called its least count L.
C ,it is also known as vernier constant. It is the difference between one main scale division which is 1 mm and one vernier division which is 0. Otherwise, the instrument has an error called zero error.
Zero error can be negative or positive. Negative Zero Error If the zero of the Vernier scale is to the left of the zero of the main scale then the error is negative. It is used for setting and measuring angles together with slip gauges, surface plate and dial test indicator.
The name Sine bar, because it works as a hypotenuse in a right angle triangle. A sine bar is specified by the distance between the center of two rollers. Sine bars are generally available in mm to mm sizes. What Is A Template? A Template is a model of an object which is designed according to required profile in least expense.
It is generally made from mild steel sheet.
To make identical parts. To check the shape of manufactured parts. Easiest method of marking identical parts. If the design of template is not suitable, it can be repaired or replaced easily.
It reduces the production cost. Unilateral Tolerance : If the variation from basic size is in one direction, system of tolerance is called unilateral. Bilateral Tolerance : If the variation from basis size is in both direction, system of tolerance called Bilateral Tolerance. Define Tolerance Zone? This is the graphical representation of the region between upper and lower limit.
It is the deviation which is conveniently chosen to define the position of the tolerance zone in relation to zero line. Define Zero Line?
Ii is the graphical representation of the basic size. The deviations are measured from this line. What Is The Actual Deviation? It is algebraic difference between an actual size and corresponding basic size. It saves the labour charges. It saves the material from wastage. It saves the time. It helps to reduce the manufacturing cost of the parts.
Shaft basis system — In this system, the size of shaft is and various classes of fits can be obtained by giving tolerance on hole Hole basis system — In this system, the size of hole is constant and various classes of fits can be obtained by giving tolerance on shafts Why The Hole Basis System Is More Popular Between The Manufacturers?
Hole basis system is more popular, because it has many advantages over the Shaft basis system, such as, It is easier to vary the size of the shaft than that of hole More adaptable to produce hole of standard size than that of shaft, because of majority of hole in engineering works is finished to its nominal size by using drills and reamers of standard size.
Clearance Fit — It is a kind of fit which always provides clearance with positive allowances. The tolerance region of the hole is above than that of the shaft. Transition Fit — This type of fit always has close providing by either a clearance or an interference. The tolerance region of the hole and shaft overlaps. Interference Fit — It is a fit which always provides interference with negative allowances.
The tolerance region of the hole is below the size than that of the shaft. Interchangeability is that the manufacturing of similar components under mass production can be assembled and replaced without any further treatment as well as without affecting the functioning of the component.
It saves time and labor charges. It gives more employment due to mass production. Improves the efficiency of workers. Easy to assemble due to International trade mark. Minimize overall production cost. Explain Briefly On Is: Scope.
This standard makes recommendations relating to limits of size of parts or components and to fits constituted by their assembly. When the parts are to be assembled, the relation resulting from the differences between the sizes before assembly is known as Fit. Depending up on the limits of the hole or shaft, the fit may be a clearance, a transition or an interference. Hole Basis System. In this standard, the different clearances and interference are obtained in associating various shafts with a single hole, whose upper deviation is zero and the symbol is H.
Shaft Basis System. In this, the different interference and clearances are obtained in associating various shafts with a single shaft, whose upper deviation is zero and the symbol is h. Indication of Fit. A fit is indicated by the basic size common to both components followed by symbols corresponding to each component, the hole being quoted first.
Production of a unit, component or part in large scale or number is called mass production. Time consumption of manufacturing.
Interchangeability of products. Selective Assembly — This assembly is slow and expensive, also the maintenance is difficult to manage since the spares are not easily available. For example special threaded nut and bolt in which each nut fits only one bolt. Non-Selective Assembly — It is quiet rapid and less expensive, maintenance is very easy since the spares are widely available. For example any nut fits on any bolt of same size and the type of thread.
What Is Lapping? Lapping is an operation of finishing the flat and the cylindrical surfaces to a fine degree of accuracy by means of a lap and lapping compound. It may be done by hand or by machine. To finish the job up to the last digit of accuracy.
To get good surface finish. To control the size. To get desired fit. What Is Honing?