Now we're going to start to move in that direction. That's it, now. I'm going
to move a little bit, like that. A little bit. Initially when you do it you'll
probably do this. Move it, come across, move it, till you get the hang of it.
And then as you get the hang of it, you can go a little bit faster on the
back-and-forth. Now when we get over here to where that step is, we'll be taking
off a little bit more,so you'll see more sparking. Not a not a panic situation,
The most important thing is that your back and forth movement is fast. And by
moving less this way (crossfeed) you're you're getting a better finish by moving it
in smaller steps. So you're going to start to see a little
more sparking and that's when I'll slow down on this cross feed.
Okay, we're getting less so this step must have been in reverse. Now I only fed
down about a half of thousands, so you can see there wasn't much of a step
there. Now when we come across we'll feed down. You can go back the other way.
Once you don't see any sparks, you can come over here now, you can get off of
your piece like that. Now what I was going to say is you can feed
down. If you look at this right here, you can see a lot better finishing. But you can feed down now and take a cut across it. Let's
just take about five ten thousands (0.0005).
Now we're going to go back the other way on this wheel.
A lot of patience involved with grinding. Just like now, if you go too fast
you'll get done quicker but
you'll sacrifice finish and accuracy. Remember we don't want to build up any
heat. Actually I'm trying to get you a real good finish now so I'm doing less
than a quarter turn on the cross feed. actually we call that cross feed that
we're doing now. The other direction is really called longitudinal.
Seems like forever doesn't it? But we have to do it. You have to keep our heat
down to get a good finish. When you're doing a lot of grinding, like all day for
example, periodically it's it's a good idea just leave everything set up the
way it was. Leave your wheel and everything on, lock your table, walk away
from it for a while maybe, get a drink or something like that. Because
watching this go back and forth (you know like this for a long period of time)
and you can lose concentration.
One thing is you need to be concentrating all the time when you're
on a surface grinder. I'm gonna wait until I'm totally off of there. That's why I
was saying if if you were below that rail there you can see what what
happen. We've cleaned our part we flipped it over we're ready to do the
other side. Now we won't feed down any because this being unground there could
be a high spot somewhere on here and we don't want to crash into a high spot. So
we're going to come over, make sure we're off of our part in this direction, and we
are okay. So now we're going to come back across it. See if we got a high spot on
there. There's a little high spot right there - see the spark. And it's
usually on the edges or around holes. So we can do a little bit more feed right
here. It's something you want to do because you want to be better safe than
sorry. Make sure we don't hit a high spot. We're
hitting a little bit of a high spots on the edge again. A very little spark, so
that other side was pretty flat. Let's get off of it, we're gonna feed
down about five ten thousandths (0.0005) and start going back the other way.
There we go, we're hitting now. You're going the opposite direction here.
We're going to do a clean up cut. If you were having to grind that to a dimension,
you'd have to do the stop, cleanup, take it off,
check it with micrometers or whatever method you're using, you would clean
everything up, put it back on there, know how much you got to take off put it
back on there do you touch off like we did start with. I'm going to use more on
the cross feed now because looks like all our high spots are on the outside edge.
Should be getting a spark here shortly when we get on that outer edge. There it
is, so we're definitely high on the outer edge, both sides. Let's get off of
our part. I'm sure you get off of your part when you feed down.
Back, go the other way again.
We just want to cross again there now and I think this is going to be our
last cut. So we're going to go down about a half thousands there, come across it
and I think that'll be it. Looks like we have a pretty good finish,
also which means we had a good wheel dress. And if you get a kind of a bumpy looking
finish, you might have had a bad wheel dress. You'll see what
this looks like here shortly when we get done. But I'm also doing a pretty slow on
the cross feed here. Going pretty quick and when we're going across it here. But
I think you can see that you need a lot of patience. The other thing is when you
get the opportunity to do this, your instructor
will go through the same thing I'm doing here. We
don't want you to really be afraid of it, but we want you to respect the safety.
On that last cut I like to go all the way off of it with a wheel off of it rather
than just crank away from it. Okay, we're totally off of it with the wheel, we're
going to come over here, lock it down, now we can release our chuck, tilt this up,
then we're done. We'll demagnetize it, which will scratch it a little bit,
because this is soft material. Normally when we're grinding we're using heat
treated material.