hello welcome to enots engineering i'm Alan in today's video we're looking at micrometers
we start the video by cutting the end off the drill off
to use as a dowel in the micrometer lock
we also look at how to set and adjust the micrometer
and some of the faults you'll get with a micrometer and how to overcome them
so let's go into the workshop and see how we do it
i've just set up my small rotary cutter in the vice
and fitted a small cutting disc to the end all i want to do is chop about 4 millimetre off the end of the drill
and that's because i need the same size as the drill for another project
so i'm just cutting a small piece off to use on a micrometer lock
now you can see the small piece of drill that I cut off just fit into this micrometer lock
because the original one was crushed and distorted so i've replaced it with a new one
now that fits okay i'll take this apart and show you from the beginning
those are the three parts to the spindle lock
this part fits inside
and then you have a little dowel
as you turn the outside diameter this little roller rolls down
tightens up on there and closes the gap so that's how the micrometer lock works
so the micrometer
comes apart like that
that fits in there
then you have to get the locking ring
when you reassemble the lock system onto the micrometer you can see on the top of
the micrometer there's a slot there and there's a little peg on the ring that goes into that slot
check that peg goes down inside
when you reassemble it this goes into there
and you have to get the anvil of the micrometer
through the locking ring and then you can start to
tighten it up
now this is stiff because someone's tightened the thread up on the micrometer
which it didn't need you can see when it comes out
that's locked that's unlocked
so i'll tighten this back down to the zero position
you can tell that how tight it is if i hold the micrometer sideways like that
it stays there when on this one
with this one you can't it's just too tight and i can't do anything about that i've
tried slacking in the screw off oiling it the thread has just been clamped too much
so as that's tight the ratchet won't work
it works as a ratchet but it's not turning the micrometer because it's too tight
but if i wipe the surface put a piece of paper in there
tighten that down you can see it's not far off zero
now if you need to alter that to get that to zero you use your spanner
and if you look at the back here you can see there's a it should be a hole but somebody's
altered it that much they've made it a slot and you can hook the spanner onto there
and then from this side
it needs to go the other way
on this side you can turn the barrel
can't on that one it's all locked up but you can turn the barrel
round till the zero lines with the zero for a fine adjustment
but as a micrometer it you could use it
but you're not going to get the feel on it that you need to get for accurate readings
so i'm keeping this just to spare parts really
so on this one i'll show you as you bring it down
the ratchet ratchets and you can see the zero is on zero
if it wasn't by putting the spanner in the hole at the back by turning the body
of the micrometer there around you can set it properly so the line aligns with the zero
now the other thing i need to tell you about which is useful to know
when you're using the micrometer if you're using it on a lathe or you're grinding objects
and you're always using it on a similar diameter you'll find that the anvil at the bottom will wear
and what will happen
is the bottom anvil instead of being flat
where like that because you're constantly using it on a bar
so this wears as a dish
the other anvil on the top should remain fairly flat because you're
in a different position every time you're using it
but the way you get rid of this dish in this side is by lapping the face
now i haven't got a lapping block the lapping block is a block of cast iron with grooves in it
so it's right this size and it has lots of grooves going across the face on both sides and the top
and bottom faces are ground and parallel and you put the micrometer on so the anvils come down
on each side and just rub it backwards and forwards until both faces are parallel
and you can see there's no wear in it
so to adjust the more than right micrometer i think it's the same with steroids or any other
make first of all the adjustment to the micrometer is made by tightening the friction sleeve which
is fitted to the stem which is on the nut under here that tightens the sleeve to give you a nice
feel on the thread so don't over tighten it otherwise you'll end up with these which
you can't use a ratchet
so once you've set the
the nut on here inside and you're happy with the movement
you can clean the faces bring the anvils together and the zero should line up with the datum line
now if that lines out you can adjust it with the spanner
so it gets a datum line exactly next to the zero
that's how you adjust the micrometer
that's an nought to one inch now i also have some other micrometers
i'll show you these the heads are the same
this one is a one inch to two inch
and you can see no spanner no setting piece
now as you go over an inch with a micrometer to set the micrometer you need
either the setting piece which would have been here which is the ground
piece of steel at a known size and you just use that to zero in micrometer too
It would probably be an inch so without that you'd need to use gauge blocks
or something that you know is the correct size so you can set the micrometer to zero to
it's exactly the same as well with
adjustments on these micrometers are the same on this end
they're all the same it's just a different body on these
and then the last micrometer i have is not more and right
this one's got somebody's name on and it's got helius
so i don't know whether they were because all these are virtually the same i don't know whether
they bought them off all the people and swapped them around you can see on here it's it has
all the different measurements
sixty in sixty fourths all the way around
what the reading would be on the micrometer
exactly the same as the other one the lock on the top this one works okay
that's another one to two but made by helios
i haven't got a steric one i'm afraid
so that's combination micrometer
with
imperial and metric
now i don't have a metric micrometer except that combination one which is different to the others
but these are the two thimbles imperial and metric and that show you the difference
you both have a datum line
and on the
imperial you go from naught to 25 on the thimble on the metric one it goes point five per division
so that you have one turn is point 0.5 two turns is 1 millimeter
oh well that's it for today i hope that was useful hope you enjoyed it
and we'll see you next time on enots engineering