hello welcome to Enots engineering i'm Alan in today's video we start with a bit more
information about turning tapers using the boring head and then we move on to how to
improve the finish of the part that you're turning depending on what tool you're using and the speed
and feeds we look at using an insert carbide insert and also high speed steel tool and see
the differences when are set at the same speed on the same piece of steel and the finishes you get
so let's go into the workshop and see how we do it what i forgot to mention on last week's
video was when you're using the boring head to turn a taper it's important that you get the
top of the head here parallel to your cross slide because if you put the
head in at an angle like that what happens is as you extend the head further out
you slowly take the part that you're turning either above centre or below centre of your
cutting tool so if you make sure that the top of the slide is dead parallel to your cross slide
then you know your tool will still be on centre line when you're cutting
and once you've put your boring head in the tail stock easiest way to check if this is square
or parallel just put a bar in this is a ground bar
and then you can run a dial indicator over the top here each side and then adjust it
to get it parallel and just tap it on
what i want to do today is just have a look at the difference
the tool will make the type of tool you use when cutting to the finish you get i had a
comment saying that a lot of my turning the finish looks a bit rough on there
and that they can turn and get a nice shiny finish
well that depends on a lot of things really the speed the material the tool and the cut
so what i was going to do is just machine this bar use the same speed the same
feed rate for cutting i think on this at the moment it's set to point two millimeter per rev
which is about eight thou so if you use the same feed rate and the same speed but all we'll do is
change tools we'll use this one which i used last week which is the insert
and then i've found out an old tool that i had this one which is high speed steel so
we'll compare the difference we get between an insert and not high speed steel tool
i've set them both to center line
the other thing i want to do is do different cuts i know if you're using an insert and you
only want to take a couple of thou off you'll lose the finish because these inserts like to be worked
where with high speed steel you should be able to maintain the finish so let's do
a cut with this insert
oh that's just touching at the moment so we'll put a cut on of 0.25
put the traverse on
you can see there that looks a rough finish
and it is so if we go back so i'll start that again i'll put a cut on a point two five
start again
and you see when it hits this where it's not cut it should give a better finish
you can see that very clearly this part here it's taking off a lot more than this end the
finish on this end is rough this is a bit better because we're working the tool more
taking more off let me take it right down to the depths
there
let's try the high speed steel tool
it's going in 0.25
i think you can see at this end it's a lot better finish
it's still what i would call rough you can feel the grooves in it
but it looks a lot better so let's just go in another 0.25 try it again
so looking at that high speed steel has given a better finish than the
insert which is what i would have expected the insert likes to take off a lot more material
now if i zoom in on that now i'm zoomed in as close i can get to that so that's probably
magnified the finish it's not too bad it is
it has got lines on it you can feel the grooves but it looks okay so what i need to do probably
is lower the traverse down so it doesn't travel so far per revolution
okay i've changed my travis feed to five thou per rev or 0.125
let's see if that makes any difference
there's the finish on that
it is a bit smoother
not much
not much difference but it looks better than it was before if i go back to the
let's take a cut with the insert and see what finish you get with that
now this is rougher now you can see that it's although it's
it's rubbing rather than cutting because i can feel this bar it's got hot
so on that one i would say mild steel speed about 850 what you must remember as well as
the diameter gets smaller there's less surface speed your cutting speed is actually slowing
down so you need to play around with the tool speeds and feeds to get the best finish you can
this is the finish with the carbide insert this finish with using the high speed steel tool
another carbide insert finish and finally the high speed steel tool finish and i think
high speed steel gives a better finish for the speeds and feeds i was using
on the mild steel it's difficult to show the surface finish on video
but i hope that was useful hope you enjoyed it and we'll see you next week on Enots engineering