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Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
& Manufacturing
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Professional CAD/CAM tools built on Inventor and AutoCAD
Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
Professional CAD/CAM tools built on Inventor and AutoCAD
Transcript
00:02
Blueprint, reading, dimensions and intolerance.
00:06
After completing this video, you'll be able to
00:08
identify dimension types and interpret dimensional tolerances
00:14
for this video.
00:15
We want to begin with the supplied data set
00:17
precision machine and caliper dash inch drawing dot PDF.
00:21
We're gonna be taking a look at this PDF drawing of the
00:24
caliper which is going to be the focus of our courses.
00:27
Now, on the left hand side of this PDF note that we have several different sheets,
00:31
we've got a main page, an exploded view caliber front, rear and piston.
00:37
Now on the main page,
00:38
we have information about the general design that we're working on the name of the
00:42
project per potentially the revision of the project
00:46
and part number weight and so on.
00:48
As we move through the different sheets,
00:50
we're gonna get additional information on the second sheet.
00:53
We have an exploded view of the assembly.
00:55
This highlights the three different machine components that we'll be making.
00:60
The caliper front, which is item number one, the caliper rear,
01:03
which is item number two and the piston which is item three.
01:07
We can see in the parts list that we have two of the piston so quantity two
01:12
and then we have one of the front caliber and one of the rear caliper parts.
01:16
As we move through to individual detailed drawings of the specific parts,
01:20
we get more information.
01:22
We now have an idea of the projection type of the drawing
01:26
information about tolerances located in the title block at the bottom,
01:30
right,
01:30
more information about the specific part number or drawing number,
01:34
the approval and the material and so on.
01:37
When we have a detailed drawing,
01:39
it's important that we identify a handful of areas and make
01:42
sure that we understand the data that we're looking at.
01:45
The first thing that we want to identify is
01:47
that we have several different views of the part.
01:49
We have a front view, a top view,
01:52
potentially different side views and section views.
01:55
Each of these are in the drawing to represent
01:58
specific information that's critical for manufacture or for inspection.
02:03
Now, when we take a look at these,
02:04
you can see that the main view does list several different dimension types.
02:09
There is a dimension for the diameter of this hole 0.255 plus or minus 0.4.
02:15
There's a diameter of this hole 0.313 plus or minus 0.5.
02:21
Some dimensions will not have additional tolerance values on it.
02:25
For example, the depth of the bore where the piston goes is 0.65.
02:29
For that information,
02:31
we need to take a look in the bottom section of our title
02:33
block and note any specified tolerances based on the number of decimal places.
02:40
So if we zoom in a little bit and we go down to the bottom section of our title block,
02:44
we can see here that any of the dimensions that aren't otherwise specified
02:48
as a tolerance value with two decimal places is plus or minus 20.5.
02:53
That means the depth of the bore, the distance between the bolt holes,
02:58
the heights that are listed here,
03:00
those are all plus or minus 0.5.
03:04
Anything else that has additional tolerance values is
03:07
likely going to be using a tighter tolerance.
03:10
For example, the piston bore at 1.6 diameter
03:14
can be up to 1.65 or down to 1.55.
03:20
And this is critical to understand because these are the ranges of
03:23
acceptable values that we can have when we machine the parts.
03:27
Some of these dimensions will also have
03:29
additional balloons or bubbles around them.
03:32
Uh Typically these are critical dimensions, things that must be inspected,
03:36
but generally when you are machining apart,
03:38
any dimension that is listed on a drawing is something that you're going to inspect.
03:43
Let's go ahead and zoom back out a little bit
03:45
and take a look at a couple of other dimensions.
03:48
You can see here that this dimension starts off with two X,
03:52
the diameter symbol and 20.255 plus or minus.
04:01
When we have a dimension listed like this,
04:03
it's important to note that the two X generally represents that
04:06
there are two instances of that specific hole on the caliper.
04:11
This is a symmetric part we can see on the other side,
04:14
there looks to be another identical hole.
04:17
Sometimes you'll see the letters T Y P for typical listed on specific features,
04:22
things like a file radius value.
04:25
Now, if that same radius value is used across the entire design,
04:28
a lot of times you'll see a single dimension and
04:30
T Y P listed for that as the typical value.
04:35
That way anything else that isn't specifically called out as
04:37
a different value will be that typical measured value.
04:41
When we have symbols like this,
04:43
we can see that we're listing a diameter which is
04:45
the hole or the passing hole that we have here.
04:48
And then we have a counter bore, that counter bore is a diameter of 0.38.
04:53
There's no additional tolerance listed.
04:54
So it's plus or minus 0.5 as specified in the title block.
04:59
Now, you'll note that we don't have a distance or a depth of that hole.
05:02
And we have to look at another view
05:03
here. We can see 0.44 is listing the depth of that
05:07
if we move on to the caliper rear, this is a very similar drawing.
05:11
We have section views.
05:12
We have information about specific holes and features,
05:16
but we also have a new type of dimension listed.
05:18
Now, this is two X.
05:19
Again, there are two instances of this hole,
05:22
but this time it is a quarter dash 20 UN C or a course thread with a two B fit.
05:29
Now,
05:29
this tells us all we need to know about how that hole needs to be drilled and tapped.
05:33
It gives us the information knowing that it is a quarter
05:40
we can see in the section view E E
05:43
which is represented here going through the caliper,
05:46
this is a blind hole.
05:48
So more information is needed when we're talking about
05:50
gathering some of these dimensions from a 3D model.
05:54
But a lot of the information is critical is listed here on the detailed drawing
05:59
as we move over to the last sheet. This is the piston.
06:02
Now, it is important to note that just because you have a detailed drawing
06:06
doesn't necessarily mean that it is 100% accurate or correct
06:11
if there's anything that stands out on a detailed drawing,
06:14
for example, the 1000.1 and 0.2 champers listed here,
06:18
those values in respect to the rest of the model seem to be a little bit large
06:24
because we only have the detailed drawing at this point.
06:27
We don't necessarily know if they're wrong or not.
06:29
But sometimes looking at a detailed drawing,
06:32
you can pick out information that may or may not be accurate.
06:35
It's important that you always question anything that doesn't
06:38
appear to be accurate in a detailed drawing.
06:41
The detailed drawing is going to be a conversation between
06:44
the designer and the person who is manufacturing the part.
06:49
You'll also note that in the title block,
06:51
there is no name or stamp for approval on this specific sheet.
06:56
If we go back to the caliper rear and caliper front,
06:59
we can see that the front has an approval but the rear and the piston does not.
07:04
While this may be a simple oversight, these are all things that should be identified
07:08
as you should never make or produce a
07:10
part that hasn't already been reviewed and approved
07:13
at this stage.
07:14
Go ahead and look back through each sheet of the detailed drawing and
07:17
identify specific dimensions and information before moving on to the next step.
Video transcript
00:02
Blueprint, reading, dimensions and intolerance.
00:06
After completing this video, you'll be able to
00:08
identify dimension types and interpret dimensional tolerances
00:14
for this video.
00:15
We want to begin with the supplied data set
00:17
precision machine and caliper dash inch drawing dot PDF.
00:21
We're gonna be taking a look at this PDF drawing of the
00:24
caliper which is going to be the focus of our courses.
00:27
Now, on the left hand side of this PDF note that we have several different sheets,
00:31
we've got a main page, an exploded view caliber front, rear and piston.
00:37
Now on the main page,
00:38
we have information about the general design that we're working on the name of the
00:42
project per potentially the revision of the project
00:46
and part number weight and so on.
00:48
As we move through the different sheets,
00:50
we're gonna get additional information on the second sheet.
00:53
We have an exploded view of the assembly.
00:55
This highlights the three different machine components that we'll be making.
00:60
The caliper front, which is item number one, the caliper rear,
01:03
which is item number two and the piston which is item three.
01:07
We can see in the parts list that we have two of the piston so quantity two
01:12
and then we have one of the front caliber and one of the rear caliper parts.
01:16
As we move through to individual detailed drawings of the specific parts,
01:20
we get more information.
01:22
We now have an idea of the projection type of the drawing
01:26
information about tolerances located in the title block at the bottom,
01:30
right,
01:30
more information about the specific part number or drawing number,
01:34
the approval and the material and so on.
01:37
When we have a detailed drawing,
01:39
it's important that we identify a handful of areas and make
01:42
sure that we understand the data that we're looking at.
01:45
The first thing that we want to identify is
01:47
that we have several different views of the part.
01:49
We have a front view, a top view,
01:52
potentially different side views and section views.
01:55
Each of these are in the drawing to represent
01:58
specific information that's critical for manufacture or for inspection.
02:03
Now, when we take a look at these,
02:04
you can see that the main view does list several different dimension types.
02:09
There is a dimension for the diameter of this hole 0.255 plus or minus 0.4.
02:15
There's a diameter of this hole 0.313 plus or minus 0.5.
02:21
Some dimensions will not have additional tolerance values on it.
02:25
For example, the depth of the bore where the piston goes is 0.65.
02:29
For that information,
02:31
we need to take a look in the bottom section of our title
02:33
block and note any specified tolerances based on the number of decimal places.
02:40
So if we zoom in a little bit and we go down to the bottom section of our title block,
02:44
we can see here that any of the dimensions that aren't otherwise specified
02:48
as a tolerance value with two decimal places is plus or minus 20.5.
02:53
That means the depth of the bore, the distance between the bolt holes,
02:58
the heights that are listed here,
03:00
those are all plus or minus 0.5.
03:04
Anything else that has additional tolerance values is
03:07
likely going to be using a tighter tolerance.
03:10
For example, the piston bore at 1.6 diameter
03:14
can be up to 1.65 or down to 1.55.
03:20
And this is critical to understand because these are the ranges of
03:23
acceptable values that we can have when we machine the parts.
03:27
Some of these dimensions will also have
03:29
additional balloons or bubbles around them.
03:32
Uh Typically these are critical dimensions, things that must be inspected,
03:36
but generally when you are machining apart,
03:38
any dimension that is listed on a drawing is something that you're going to inspect.
03:43
Let's go ahead and zoom back out a little bit
03:45
and take a look at a couple of other dimensions.
03:48
You can see here that this dimension starts off with two X,
03:52
the diameter symbol and 20.255 plus or minus.
04:01
When we have a dimension listed like this,
04:03
it's important to note that the two X generally represents that
04:06
there are two instances of that specific hole on the caliper.
04:11
This is a symmetric part we can see on the other side,
04:14
there looks to be another identical hole.
04:17
Sometimes you'll see the letters T Y P for typical listed on specific features,
04:22
things like a file radius value.
04:25
Now, if that same radius value is used across the entire design,
04:28
a lot of times you'll see a single dimension and
04:30
T Y P listed for that as the typical value.
04:35
That way anything else that isn't specifically called out as
04:37
a different value will be that typical measured value.
04:41
When we have symbols like this,
04:43
we can see that we're listing a diameter which is
04:45
the hole or the passing hole that we have here.
04:48
And then we have a counter bore, that counter bore is a diameter of 0.38.
04:53
There's no additional tolerance listed.
04:54
So it's plus or minus 0.5 as specified in the title block.
04:59
Now, you'll note that we don't have a distance or a depth of that hole.
05:02
And we have to look at another view
05:03
here. We can see 0.44 is listing the depth of that
05:07
if we move on to the caliper rear, this is a very similar drawing.
05:11
We have section views.
05:12
We have information about specific holes and features,
05:16
but we also have a new type of dimension listed.
05:18
Now, this is two X.
05:19
Again, there are two instances of this hole,
05:22
but this time it is a quarter dash 20 UN C or a course thread with a two B fit.
05:29
Now,
05:29
this tells us all we need to know about how that hole needs to be drilled and tapped.
05:33
It gives us the information knowing that it is a quarter
05:40
we can see in the section view E E
05:43
which is represented here going through the caliper,
05:46
this is a blind hole.
05:48
So more information is needed when we're talking about
05:50
gathering some of these dimensions from a 3D model.
05:54
But a lot of the information is critical is listed here on the detailed drawing
05:59
as we move over to the last sheet. This is the piston.
06:02
Now, it is important to note that just because you have a detailed drawing
06:06
doesn't necessarily mean that it is 100% accurate or correct
06:11
if there's anything that stands out on a detailed drawing,
06:14
for example, the 1000.1 and 0.2 champers listed here,
06:18
those values in respect to the rest of the model seem to be a little bit large
06:24
because we only have the detailed drawing at this point.
06:27
We don't necessarily know if they're wrong or not.
06:29
But sometimes looking at a detailed drawing,
06:32
you can pick out information that may or may not be accurate.
06:35
It's important that you always question anything that doesn't
06:38
appear to be accurate in a detailed drawing.
06:41
The detailed drawing is going to be a conversation between
06:44
the designer and the person who is manufacturing the part.
06:49
You'll also note that in the title block,
06:51
there is no name or stamp for approval on this specific sheet.
06:56
If we go back to the caliper rear and caliper front,
06:59
we can see that the front has an approval but the rear and the piston does not.
07:04
While this may be a simple oversight, these are all things that should be identified
07:08
as you should never make or produce a
07:10
part that hasn't already been reviewed and approved
07:13
at this stage.
07:14
Go ahead and look back through each sheet of the detailed drawing and
07:17
identify specific dimensions and information before moving on to the next step.
After completing this video, you’ll be able to:
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