Screw Gauge Measurement and Experiment

Exact measurements are a necessity in the scientific field. To measure a spherical or a cylindrical object, a screw gauge is the best instrument. An extremely fine-tuned screw gauge can be a bit difficult for untrained hands to use. Here, we will see how to use a screw gauge.

Measurement Using the Micrometer

• Get acquainted with the structure of a screw gauge – Some of the sections are movable, while others are stationary.
• Anvil
• Spindle
• U-Frame
• Main scale
• Sleeve
• Thimble
• Circular scale
• Ratchet
• Before starting to measure, clean the spindle and anvil – Take a piece of paper or a clean cloth and place it in the midst of the spindle and the anvil. Tighten the setup slightly until the paper or cloth is jammed, and then pull it out, cleaning the setup in the process. This step is not necessary to do but helps in getting a clear measurement, as preciseness is indispensable.
• Place the object in between the spindle and anvil – Place the object carefully in between the anvil and the spindle. The anvil is stationary in nature; thus, place the object against it. The object should be placed properly so that it does not move while taking the measurements.
• The ratchet counter needs to be rotated clockwise to tighten – Make sure that the thimbles zero is parallel to the line of the scale on the sleeve.
• Tighten the spindle with the object in the midst – The thimble clicks when being rotated. Apply the amount of force till it clicks three times.
• Lock the thimble while the object is in between – The spindle can be moved even if the thimble is locked. This will help you get a precise reading easily.
• Take the object out cautiously – The screw gauge’s accuracy can get compromised, if it gets scratched or shaken, and thus make sure to avoid that.
• Before you unlock the spindle, note the reading – Re-measure the whole setup if the single setup loosens.

Measurement Using the Inch Micrometer

• The thimble has a lot of different scales. Learn them.
• There is a scale that takes the measure by one hundred thousand’s, i.e., one-tenth of an inch, or the decimal form is 0.100.
• Spreads in between those numerics are three lines that are a representation of twenty-five thousandths of an inch, which, if represented in decimal, will be 0.025.
• The uniformly spaced lines are a representation of one-thousandth of an inch; when represented in a decimal form, it’s written as 0.001.
• The whole number scale that is represented by the lines on the sleeve is a measure of ten-thousandths of an inch; when represented in decimal form, it’s written as 0.0001.
• The sleeve has whole numbers – The number that’s visible at last is a representation in thousandths. For instance, if the last number is 6, it would be finally represented as or 0.500.
• Note the number of lines after the whole number – Notice the markings next to the 100 thousandth mark and then multiply that by 0.25.
• Notice the marking that’s corresponding to the thimble scale marking (closest to it and beneath the measurement line).
• The three numbers noted down in the earlier process should be noted and added.

Units & Dimensions – Screw Gauge

Units & Dimensions – Important Questions