Screw Gauge - Definition, Formula, FAQs

What is a Screw gauge Scale Using Micrometer unit

Screw gauge is a tool that usually makes it easy to measure the width or radius or the thickness of a thin wire or even the thickness of a thin metal wire with great accuracy.
This tool consists mainly of a U-shaped frame and a nail (or screw) attached to a thimble. There are usually two scales known as the Pitch of screw gauge Scale which is a large scale and is written on a barrel with vertical lines. The other is a circular circle inscribed horizontally on the thigh. Pitch of screw gauge scale measures the distance in millimeters (mm) propelled by a spindle for each change. Another change in a circular motion equal to half a millimeter of screw transfer is called a micrometer screw gauge. Micrometer scales are very accurate and accurate compared to the Vernier Caliper scale.

Before you start measuring, it is important to make sure that the 'Stud-end' and 'Spindle (or Screw) end' areas are cleaned; otherwise the measurements obtained will provide the wrong size.

‘Anvil’ motionless and attached to the U-shaped frame. When the anvil and the spinning tin (or screw) are touched, the Pitch of screw gauge Scale zero (or large zero scale) must correspond to the zero of the circular scale. This is considered a reference.

As the anvil is repaired, therefore, it is appropriate to place the object, its size to be measured, firmly near the temple. At the same time, a circular thimble at one end of the gauge needs clockwise rotation. This action will cause the spinning section (or screw) to move forward in the direction of the anvil. Continue to rotate the sceptre so that the spindle (or screw) reaches the object, which is placed near the temple.

In the latter case, the object, the size of which is available, must be held firmly and firmly between the temple and the tile. A three-click Ratchet is used as long as a direct spinning operation is performed. This position can be locked using the lock key located next to the spinning wheel.

Once the previous step is detected, the pitch of screw gauge scale and the circular scale should be read. Pitch of screw gauge scale reading is the significance of the Pitch of screw gauge scale when it touches the sleeve of a circular scale. Round scale reading is a line-based reading on a pitch of screw gauge scale. A magnifying glass can be used to read measurements. Suppose a reading of a field is 'X' and a circular reading is a 'Y'.

The final calculation will be as follows:

Total reading = X (mm) + (Y x LC gauge) mm

Here, LC is a very small number of gauges.

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Screw gauge measurement using Inch Micrometer. Define gauge.

The value of the pitch of screw gauge scale is calculated in half an inch. The number 5 (or graduation 5) in the barrel means half an inch or 0.500 inches. There are 4 stages between graduation 0 and graduation 1 on the pitch of screw gauge scale. Therefore, the first graduation seen in the bin as number 1 is actually 10th inch or 0.100 inches or 100th of 1000 inch. Similarly 2 graduates are 0.200 inches or 200th of 1000 inches or 20 200 inches. So the smallest separation on the pitch of screw gauge scale can be 0.025 inches or 25th of 1000 inches.

Screw gauge formula: micrometer least count formula

Pitch of screw gauge scale measures the distance in millimeters (mm) that the spindle moves by each turn. The volume of the screw pitch gauge scale is calculated as given below:

Pitch of screw gauge of the Screw gauge = The distance travelled by the screw Rotation value

To measure the size of a small wire or a small sheet using a screw gauge, one needs to know a small calculation. The minimum screw pitch gauge calculation can be calculated using the formula given below:

Small screw gauge calculation = Screw Number Pitch of screw gauge for circular scale sections

Once the minimum number of gauges has been calculated, the final reading is calculated as below

Complete Reading = High Level Reading + Circular Circle reading x LC gauge.

The LC in the above equation is a small gauge calculation. There may be a chance that the zero of the pitch of screw gauge scale does not correspond to the zero of the circular scale. In that case, either the scale can be above or below the pitch of screw gauge scale (also known as the larger scale).

If the zero of the circular scale is less than the pitch of the screw gauge scale, it is known as the correct zero error. The value of the circular separation below the pitch of screw gauge scale should be multiplied by a small gauge count. This value should be deducted from the full study of the appropriate values. So the formula is as follows:

Complete Reading = Circular Scale Reading

If the zero of the circular scale exceeds the pitch of the screw gauge scale, it is known as a non-zero error. The value of the circular separation above the pitch of screw gauge scale should be multiplied by a small gauge count. This number will be included in the full study of the relevant estimates. So the formula is as follows:

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Complete Reading = Circular Scale Reading

An example of how to read a screw gauge measure using a micrometer is discussed.

If a micrometer has a pitch of screw gauge of 0.5 mm. It means that with one complete rotation of the thimble scale, a distance of 0.5 mm travels through the thread. There are 50 sections on a circular scale. The minimum calculation will be 0.01 mm calculated as below.

Minimum number = Pitch of screw gauge Number = 0.550 = 0.01mm

Hence the pitch of screw gauge scale reading is 3 mm. According to a circular scale reading, 46 divisions are like a reference line on a pitch of screw gauge scale. So the full reading will be

Complete Reading = High Level Reading + Circular Circle reading x LC gauge

= 3mm + 46 × 0.01 mm = 3.46 mm.

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NCERT Physics Notes:

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