01. New Symbols - 2009 Standard - Technical Training Consultants
01. New Symbols - 2009 Standard - Technical Training Consultants
01. New Symbols - 2009 Standard - Technical Training Consultants
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856 SALT LAKE COURT SAN JOSE, CA 95133 (408) 251–5329<br />
<strong>New</strong> <strong>Symbols</strong><br />
<strong>New</strong> symbols in the <strong>2009</strong> Revision of the GD&T <strong>Standard</strong> 1<br />
ALL OVER<br />
CONTINUOUS FEATURE<br />
SPOT FACE<br />
INDEPENDENCY<br />
UNEQUALLY DISPOSED PROFILE<br />
CF<br />
SF<br />
I<br />
U<br />
DATUM TRANSLATION<br />
MOVABLE DATUM TARGET SYMBOL<br />
A1<br />
Figure 3-1 <strong>New</strong> symbols used on prints<br />
Tolerance<br />
Zone<br />
Figure 3-2 All Over symbol<br />
<strong>Technical</strong> <strong>Training</strong> <strong>Consultants</strong> (408) 251-5329 http://www.ttc-cogorno.com
The All over symbol, used with the profile control, consists of two small concentric circles<br />
placed at the joint of the leader connecting the feature control frame to the feature. Where the all<br />
over symbol is specified, the profile applies all over the three-dimensional surface of the part as<br />
shown in Fig. 3-2.<br />
Ø1.00-1.02<br />
CF<br />
Figure 3-3 Continuous feature symbol<br />
The Continuous feature symbol specifies that a group of two or more interrupted features of size<br />
are to be considered one single feature of size shown in Figure 3-3.<br />
Ø.750<br />
$Ø1.000^.625<br />
Depth Symbol<br />
Counterbore Symbol<br />
Ø.500<br />
%Ø.875 X 82°<br />
Countersink Symbol<br />
Ø.280<br />
SF Ø.630<br />
Spotface Symbol<br />
Figure 3-4 Spotface symbol<br />
Where a Spotface is indicated, either the depth or the remaining thickness of the material may be<br />
specified. If no depth or remaining thickness is specified, the spotface is the minimum depth<br />
necessary to clean up the surface of the specified diameter.<br />
<strong>Technical</strong> <strong>Training</strong> <strong>Consultants</strong> (408) 251-5329 http://www.ttc-cogorno.com
Ø.500-.505<br />
I<br />
Figure 3-5 Independency Symbol<br />
The Independency symbol, circle I, indicates that perfect form of a feature of size at MMC or<br />
LMC is not required. However, a supplementary form tolerance(s) may be required to limit<br />
excessive variations of form as shown in Fig. 3-5.<br />
Figure 3-6 Unequally disposed profile symbol<br />
The Unequally Disposed Profile symbol, circle U, indicates a unilateral tolerance or a tolerance<br />
unequally disposed about the true profile. This symbol shall be placed in the feature control<br />
frame following the tolerance value as shown in Fig. 3-6. The tolerance that would allow<br />
additional material added to the true profile is place after the circle U.<br />
1 Cogorno, Gene R., Geometric Dimensioning and Tolerancing for Mechanical Design, Second<br />
Edition, McGraw-Hill, <strong>New</strong> York, 2011, pp. 24 and 117.<br />
<strong>Technical</strong> <strong>Training</strong> <strong>Consultants</strong> (408) 251-5329 http://www.ttc-cogorno.com
A1<br />
B1<br />
2.125<br />
6.000<br />
C1<br />
45°<br />
.750<br />
45°<br />
.750<br />
B2<br />
Ø 2.000<br />
A2<br />
2X Ø.260-.280<br />
A3<br />
C2<br />
B1<br />
B2<br />
.250<br />
.500<br />
C1<br />
C2<br />
A<br />
1.000<br />
A1<br />
A2<br />
A3<br />
Figure 4-8 Movable Datum targets equalizing datum features<br />
The Movable Datum Target symbol indicates that a datum target is not fixed at its basic<br />
location and is free to translate.<br />
Datum Translation<br />
Symbol<br />
n]w.005]A]B]C ]<br />
Figure 3-7 Datum Translation symbol<br />
The Datum Translation symbol indicates that a datum feature simulator is not fixed and is free<br />
to translate within the specified geometric tolerance to fully engage the feature.<br />
The maximum material boundary of a datum feature applies at its virtual condition with respect<br />
to the previous datum feature. In the drawing on the next page, datum feature D is specified with<br />
a datum translation symbol. The datum translation symbol allows datum feature D to translate<br />
with respect to datum feature B. Consequently, datum feature B is no longer part of the location<br />
equation; the maximum material boundary of datum feature D is 1.005, which is the virtual<br />
condition of datum feature D with respect to datum feature A. The gage, shown below, must first<br />
mate with datum feature A and then with datum feature B. But the translation symbol allows<br />
datum feature D to translate back and forth with respect to datum feature B. In this case, datum<br />
feature simulator D is not located to datum feature simulator B. Datum feature simulator D is a<br />
slot whose width is produced 1.005 wide, the virtual condition of datum feature D with respect to<br />
datum feature A. Datum feature simulator D controls clocking about datum feature B.<br />
<strong>Technical</strong> <strong>Training</strong> <strong>Consultants</strong> (408) 251-5329 http://www.ttc-cogorno.com
.505-.510<br />
C<br />
5.000<br />
.005 M A B M<br />
Ø.995-1.000<br />
D<br />
.010 M A B M C M<br />
.005 M A<br />
Ø1.000-1.010<br />
.005 M A<br />
Ø.495-.500<br />
n]w.005m]A]Bm]Dm ]<br />
.002<br />
B<br />
5.000<br />
Part<br />
A<br />
1.005<br />
Slot<br />
Ø.490<br />
Ø.995<br />
Gage-Makers' Tolerance<br />
Gage<br />
<strong>Technical</strong> <strong>Training</strong> <strong>Consultants</strong> (408) 251-5329 http://www.ttc-cogorno.com
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