1
00:00:14,208 --> 00:00:16,375
Hello, and welcome
 back to Heart of Worcestershire College.

2
00:00:16,458 --> 00:00:17,750
My name's Howard. 

3
00:00:17,750 --> 00:00:21,250
Today we're going to be following on
 with the latest in the toolbox talks.

4
00:00:22,500 --> 00:00:26,416
So today we're going to be talking about
 the solutions of the right angle triangle

5
00:00:26,791 --> 00:00:29,625
because as engineers, we've quite often

6
00:00:30,041 --> 00:00:32,291
require to machine a certain angle.

7
00:00:33,916 --> 00:00:37,125
Let me just show you
 an example of some of the milled work

8
00:00:37,125 --> 00:00:39,500
that we do that has an angle on it.

9
00:00:41,875 --> 00:00:43,958
So we need to be able to set up 

10
00:00:43,958 --> 00:00:46,833
accurately the machine that angle, 

11
00:00:46,833 --> 00:00:48,833
so how I'm going to do that 

12
00:00:48,833 --> 00:00:50,875
is I'm going to use this device here,

13
00:00:51,500 --> 00:00:54,041
which is called a sine bar. 

14
00:00:54,250 --> 00:00:56,916
This is a 100 millimeter sine bar.

15
00:00:56,916 --> 00:01:01,000
That means the centers of these two
 precision rollers is exactly

16
00:01:01,000 --> 00:01:02,500
100 millimeters. 

17
00:01:02,500 --> 00:01:04,833
Now, as we move this up,

18
00:01:05,875 --> 00:01:07,291
we can put a stack of slips 

19
00:01:07,291 --> 00:01:10,166
under here
 to determine what size we need it.

20
00:01:11,250 --> 00:01:15,666
Now, the easiest example to show you
 this is 30 degrees,

21
00:01:16,041 --> 00:01:21,000
because using the solutions of the right
 angle triangle where the capital A, B

22
00:01:21,000 --> 00:01:25,916
and C are the angles and the lower case
 a, b and c are the sides,

23
00:01:26,666 --> 00:01:29,666
we need to find what this is,
 which is the B.

24
00:01:30,416 --> 00:01:32,666
So by going by our known data,

25
00:01:33,208 --> 00:01:36,666
we know the hypotenuse is 100 mil.

26
00:01:38,250 --> 00:01:42,333
We need to find out what lowercase b is.

27
00:01:44,750 --> 00:01:48,958
Uppercase B is 30 degrees,
 so we've got a find b.

28
00:01:48,958 --> 00:01:53,666
b equals A multiplied by the sine of B.

29
00:01:54,500 --> 00:01:57,916
The sine of B, which is 30 degrees

30
00:01:59,625 --> 00:02:02,333
is 0.5, exactly 

31
00:02:02,333 --> 00:02:05,625
which is why I picked it
 for an example of how to do this.

32
00:02:06,666 --> 00:02:08,791
So I'll go to my boxes slips.

33
00:02:10,333 --> 00:02:12,583
This is a 50 mm slip.

34
00:02:14,166 --> 00:02:16,666
I put that under there. 

35
00:02:17,833 --> 00:02:21,458
We have a digital protractor here. 

36
00:02:23,791 --> 00:02:26,791
Which is displaying zero. 

37
00:02:27,583 --> 00:02:30,541
Put this on the sinebar. 

38
00:02:31,958 --> 00:02:35,125
It's fluctuating between 3 and 3.1.

39
00:02:36,166 --> 00:02:37,500
Ideally, we should be doing this 

40
00:02:37,500 --> 00:02:41,000
on a surface table,
 so this toolbox will flex a little bit.

41
00:02:41,291 --> 00:02:43,583
This is to give the idea
 of how we work this out.

42
00:02:45,083 --> 00:02:47,666
So if we set this to the right angle
 now, we can

43
00:02:47,666 --> 00:02:49,750
then put our piece on here

44
00:02:51,666 --> 00:02:54,250
and with the milling cutter, 

45
00:02:54,250 --> 00:02:56,125
we can actually 

46
00:02:56,208 --> 00:02:58,208
machine that angle. 

47
00:02:58,208 --> 00:03:00,291
That's how we set up for a certain angle.

48
00:03:01,458 --> 00:03:03,458
OK, thank you for watching.