today i'm going to be demonstrating how to use a vernier micrometer
by measuring a valve shim from a high performance motorcycle engine
the valve shims are a critical component to the engine and have to be exact. that little piece
of metal goes on top of the valve and takes up the space between the valve and the camshafts
and if it's not exact then things like the valves can end up hitting the pistons on the top side and
causing problems. when these parts are turning at over 14 000 rpm you can see why it's critical
to have them so precise. whether it's on a piece of paper or an excel file like i've done you want
to set it up so that you have the measurements for your two sleeve measurements one thimble
measurement and one vernier measurement and you can see i've noted them as the sleeve being a 100
000 measurement then in increments of 25 thousands measurements then the 1000 then the 1 10 000.
the first thing to do is make sure that your micrometer is zeroed out so if we move it
all the way in by rotating the thimble here and then finish by rotating in the ratchet
and what we want to see is that the zero line on the thimble lines up with the zero line
across from it on the vernier. perfect okay so now we rotate it back and we give it a little
bit of space to insert our valve shim. okay now that the valve shim is in place i'm going to
turn it pretty close and when there's almost no play left i'm going to rotate the ratchet
and that's going to be the final spot. look at the vertical lines on the sleeve
down there and you can see it goes zero and then little lines and then the one so what that one
represents and the one is the last whole number you see before the thimble starts so that one
represents a hundred thousands so i'm gonna go put a hundred thousands on my spreadsheet
for that line. now you see on the sleeve there's that one little line after the one
and that represents another 25 thousands so i'm gonna go put another 25 thousands
into my spreadsheet and now we want to look at the thimble which is this part right
and the last number before the zero line you can see is that one right and it's right
below the zero line so one is the number we're taking away from there and that one represents
another thousandth. okay so we're going to enter 0.001 into the spreadsheet the last measurement is
the actual vernier and what you're looking for see how the zero line is a little higher than the one
on the right and then the one is just a little higher than the two on the right and the two
the two is getting pretty close the vernier as far as lining up with line and then three is a
little bit lower so what you want to do is pick the one that it's most matched to and
if you look across there it looks like the two on the vernier which is on the left like that two is
the one that lines up closest with a line on the thimble so that two is another two ten thousands
so we're going to enter point zero zero zero two into the spreadsheet now you can see in this
spreadsheet i already had the math pre-populated so that it just sums up those values and then you
get a number of 0.1262 inches. now i can take that number basically enter it in over here
enter and then it calculates out that it's about 3.2 millimeters for me.
i'll repeat this on down the line for the 16 shims
and that's how you use a vernier micrometer to measure a valve shim subscribe to my youtube
channel if you want to learn more about how to enjoy amazing machines like this.