Hello welcome to Enots engineering I'm Alan
in this video we set the compound slide to 8 degrees accurately by using trigonometry
I didn't look at the compound slide scale so I had no idea what angle it was set to
just by using trigonometry you can set the angle exactly
I first saw this method on Joe Piezynski's advanced innovations channel
where he used the same method to set his compound slide
So I can check whether my ER32 collet holder has the correct angle
so let's go into the workshop and see how we do it
I was just checking my ER32 Collet holder in the bore
I've put some red felt-tip pen along put a collet in with the dowel in
so the collet won't squash down
put that inside turn it
and then you can see
inside where it's rubbed the line off
which is three-quarters of a way along
so it looks as if the taper on the inside is slightly out
now if it's gripping on the back it means the front could move slightly
giving you the excess run-out
so what I want to do is set the compound slide
to the correct angle eight degrees dead-on
so that I can then run the dial indicator along to see how much out the taper is
now to set the angle dead-on you need to work out some dimensions
for turning this taper we use the compound slide
I know it should be 8 degrees
so I would have to set it this way 8 degrees
and move the top slide across to give you the angle I want
now I don't know whether the angles on this Boxford are accurate
so I don't want to use the angle here
in fact what I'll do so I'll put some tape over it so we can't see what the angle is
what do we need to know to work out the angle
we need to know the angle we're looking for as I said on these tapers I think it's 8 degrees
and then we need to know a length that we can move to work out our 8 degree from
first thing we need to do is check how far our compound slide will move
so what I'm going to do turn this right to the end of the travel
back it off a little bit half a turn and set that to zero
so I'll take the backpack out because we want to wind this back because it's fully forward
first of all I'll mark the edge here of pencil the straight edge
that's my first reference mark
and then I will count the number of turns on this
now I know each turn is 2.5 millimetres
so we've got one two three
so if I bring you back to zero there that's the end of the travel
we've got 26 turns
what I'll do now is mark this line on here
it's only a visual indication of the position the left line is fully back
and the right line is fully forward
26 turns at 2.5 millimetre equals 65 mm
you have the top of the triangle, the hight 90 degree there
this is the 8 degrees that we want and we know this is 65mm
and what we want to work out is B on the chart
so B is equal to A x the sine of 8 degrees
If you have a calculator with the sines in
go to the calculator and we just put 8 sine
then it comes up with 0. 1 3 9 1
then we know I 65
and if he multiply that by 65 it comes up with 9.046
and that was B
now if you can't be bothered with all these trigonometry or you're not sure how to do it
just go on to the website type in trigonometry calculator
and you'll get this come up or something similar
all you do on this is put in the angle eight degrees type the length of the side which is 65 degrees
and it works all the other parts so for you and it says that side a is 9.0462
which is what we calculated before
so now we'll transfer that information to the lathe
what I have on the lathe is a parallel bar
that's just fitted it could be in the chuck but in this case it's on a Morse taper
I know this is parallel to the centreline of the lathe
and I've got a dial indicator in my tool post
what I need to do is set the dial indicator
square to the bar
remember I don't know what angle this is set to I've coverd it over
and the calculated figure we got was 9.046 millimeters
so moving the dial indicator until it comes to the edge of the bar
I'm locking my saddle and I'll set my dial indicator height to the centre line
or you could use a flat tip on the end of the dial indicator
I'm only using my compound slide and top slide
so wind this into zero
now once you set down indicator to zero ensure that the cross slide is set to zero and zero on the compound
then wind it across 65mm until the other line meets
just here
and go to zero
I've zeroed the top slide and now I'll move that in 9.046mm
so that's
five seven and a half
eight eight and a half
9.046
about there you can see the distance i'm away
that should have touched and come to zero
so if I now slacken the compound slide off of move it round
coming to zero roughly
do it again
wind it right the way back
until your first line that's zero
and when you when you're coming up to your zero make sure you're taking the backlash out
you're not going zero on the back stroke
and then on the other one zero on the forward stroke
so that's zero zero the dial indicator on the end
now once you set your dial indicator to zero
ensure that the cross slide is set to zero
then wind it across 65mm until the other line meets
you see with the pencil lines you don't need to worry about the individual turns
come up to zero and then wind it in
in my case 9mm
five seven and a half eight and a half
9.046 mm
that's the distance
so let's have a look at the angle
you see there's the 8 degrees
virtually dead on
so by using some trigonometry you should be able to set your compound slide exactly to the angle that you need
I've just set lever indicator up
wind it along the bore
it's gone off the end there
so that's 0.1 millimetre which is about 0.004"
So the taper it's 0.004" out
You can see on the collet there
the blue is on the bottom on most of these
some are all along but this ones on the bottom that ones on the bottom
so it's rubbing mainly on the back of the collet
and I think what I'll do is try to set my grinding wheel up
to follow what I've already set up and we'll see how we can grind that taper
oh well that's it for today hope that was useful
hope you enjoyed it
look after yourself and we'll see you next time on
Enots engineering