hello guys welcome to Learning with Layi

this is the continuation video on how to take readings from vernier callipers and

micrometer screw gauge the micrometer screw gauge is quite different in

structure than the vernier calipers and it is used for measuring the diameter of

a piece of wire thin rods and object of similar small distances so let me show us

an image of micrometer screw gauge in case we might have forgotten and here with me now

from the previous video which I showed us before we have the micro screw meter

gauge with some parts labelled where we have the frame the anvil the spindle the

lock the thimble the ratchet knob sleeve and this part here now is the digitized

image of micro screw meter gauge whereby this main scale is actually what is

zoomed for us here to see and we have rotating scale we have the Thimble and

the object is actually placed in in between the spindle and the anvil and we can use

that to measure the distance of or the diameter of the thin rod or the object that

is placed there so now it is used and what we should know is that what we

should know is that there is always a pitch of 0.5 millimeters in the screw of

the thimble which now yields that 50 circular division is actually equal to 0.5 millimeters and

one circular division is actually equal to 0.1 millimeters so we have 50

circular division is actually equal to 0.5

millimeters and one circular division is actually 0.01 millimeter and I’m

actually going to explain this better so now and also in that same pitch where I

mentioned that it is of 0.5 millimeters the pitch that is in the screw which is 0.5

millimeters it means that for one for one revolution of the screw the

spindle moves forward or back 0.5 millimeters now let me take us back to that image so now in this part here now inside this thimble here there is a

pitch inside which is of 0.5 millimeter so when we turn our micro screw meter

gauge it moves forward or backward and that is occuring at one revolution and

since it is moving forward and backward it is going a distance or covering a

distance of 0.5 millimeters so now that’s the main idea that we need to know so

what we actually need to take notice that since we have our main scale here we

take down our readings then we now add that readings to the the circular

division that we have we will convert it almost like a similar case of the vernier

scale whereby we convert the vernier division to either centimeters or

millimeters depending on the manufacturer’s unit degraded on

the vernier scale so now in this case here now in it if you want to know the actual distace of this object here we are going to what we’re going to do is

that we’re going to take…. let me do it here on this page the distance of the

object d will be actually be equal to main scale reading plus rotating scale reading so

now I can also write it out on this micrometer screw gauge I’m not

actually going to repeat it so now the distance of the object let me write it

distance of object is actually going to be equal to the main scale reading plus

the rotating scale sometimes it is also called the drum circular…. from the

rotating scale rather is always having 50 circular division on the micros

micrometer screw gauge it has 50 circular division so for us to now

actually know the millimeters of the actual division the circular division

that coincides with the main scale because what we’re actually trying to look at is

the circular division that coincides with the main scale so then we now convert it to

millimeters and in most cases the unit on the main scale is always in

millimeters and while that of the circular division on the rotating scale reading

is actually equal to is also in millimeter so now let me now take us

to some examples that I’m going to solve and they’ll be a class work which you

can try to test your knowledge or understanding of it so here now I have

some readings of the micrometer screw gauge with me and we’re going to

actually write down the readings because this….

we can assume that the micrometer has been turned and this is the final

position whereby the the spindle and the anvil are actually holding onto the object

and we actually have a lock here in case if we remove the object so that the anvil and

the spindle doesn’t and shift from the initial position so now we have our

readings noted now so all what we are going to try and figure out is at what

point this is our main scale let me let me point it out so this is our main scale and this is the rotating scale here

in most cases they are always in millimeters in most cases they are

always in millimeter especially the rotating scale it is always in

millimeters now the main scale might depend on the manufacturer’s choice

whereby I can choose to put any other metric unit maybe centimeters but in most cases

the rotating scale is always in millimeters in most of text books I

checked before making this video so now how do we take down our reading now now

the formula to get the distance of the object we I tagged D is actually and

again sorry for that I omitted something so now our rotating scale reading is

going to be okay we would actually solve it here so now our main scale reading is

actually at what point we look at this now this is actually main scale because

the distance of the object which I’ve already written that I can write this as main

scale m dot s plus RS so and our main reading now is

that’s what eight point five millimeters now how do you now get the rotating

scale and the rotating scale is always in circular division

just like our vernier scale….. we count it in Vernier division then we use

that standard conversion that one vernier division is actually equal to 9 over

ten millimeters and in centimeters that will be 9 over hundred but in this case here now

we have our rotating scale and since we already figured out that for one circular

division that is going to be equal to 0.01 more millimeters therefore for and

if we look at it now the point of our coincidence with the main scale and our

circular division is actually going to be 27 because this is 25 this is 26 27 28 29 30

so this is the point here that means for 20 circular division that will now be 27 27

rather times 0.01 we have millimeters here now so that will now be actually so from here

now we will simplify this further this would be eight point five plus zero point two seven since they are both

having the same unit I don’t need to repeat that will now be eight point

seven seven millimeters this is quite straightforward than the vernier scale now

let me do B so now to solve for B now if we look at it now

this is starting from zero that’s why i closed this part here now so now we can see it now

that the main scale reading is actually our distance…is what is our main scale reading

so that actually two millimeters so I have the unit of all these main scale and

the rotating scale and the rotating in scale in most cases always in millimeters and for the vernier

scale and the main scale Main scale is mostly not… that’s manufacturer’s

choice could be either Main scale is always in centimeters

whereas the vernier scale is always in millimeters but for the micro screw for

the micrometer screw gauge the main scale is actually in

millimeters while the in some cases depending on the manufacturers choice

but rotating scale in most cases always in millimeters so now we have this also

millimeters have this also in millimeter so now to calculate the readings from

this micro meter screw gauge so we have a mainscale reading to be two millimeters

plus our rotating scale let me change that our rotating scale is actually that plus so now what point does our rotating scale coincide

with the main scale and if you look at this that’s at nine nine circular division so

this would be nine times 0.01 millimeters so now when we solve this

this would now actually be two millimeters plus zero point zero nine millimeters so

now our final answer is now going to be two point zero nine so now we can try

and solve this other ones to check our understanding about how to take readings

from a micro screw micrometer sorry micrometer screw gauge then I’m going to

write out the answers for this other ones here and the answer for this one

let me use that in another pen the answer for c is actually 10.15 millimeter and for d

the answer is actually twelve point three five so there you have it guys if you

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