Cincinnati 230 CB - Blank Development

BEND ALLOWANCES FOR SHEET METAL AIR BENDS - MILD STEEL
Until formulas, charts and bending operations are verified,
it is always best to make up an actual part before cutting a
lot of blanks.
SA
"Ren"
nl
-L I'X))
T I ~~
tLl1 ___
BLANK WIDTH:: II ... l2 - BEND AllOWANCE IBAl
MATERIAL
RECOMMENDED RECOMMENDED
THEOAEnCAl
ALLOWANCE BASIS Of
THICKNESS
DIE WIDTH
UPPER DIE eEND RADtUS
fOR 90
o
BENO
fORMULA FOR
"r"
.. v ..
RADJUS "RIM»"
Rtn"5/32 x ..v·· "SA"
CALCULATIONS
3/16 t.187S)
1-1/2
3/16
.2344
.4851
10 GA. l.134S}
1-l/8
1/8 .1151 .3605
11 GA.I.t196) 1
liS
.1562 .3203
SA=
12 GA. 1.1046)
7/8
1/8
.1367 .2803
l.S7lR •• 4TJ
13 GA. 1.0891) 3/4 1/16 .1112
.2403
14 GA. 1.07471
5/8 t/18
.0978 .2001
lS GA. 1.0613)
1/2 1/16
.0181
.1649
16 GA. 1.0598) 1/2
IllS
.0781
.1539
18 GA. 1.0500) 3/8 1/32
.0586 .118 t
20 GA. 1.03591 1/4
1/32
.0390
.0802
SA:
1.57 t R + 1/31)
21 GA. 1.03291
1/4 1/32 .0390
.0786
22 GA. 1.0299) 1/4 1/32
.0390
.0770
23 GA. 1.0269)
1/4
1/32
.0390
.0754
CalcuJatedbend allowances are approximate, not exact.
Actual dimensions can only be
found by making the bend and measuring the results.
The above formula is for right angle bends only. For gaging. remember to use only one leg
and one half of the bend allowance to approximate the distance.
FIGURE 32
Changing material, die opening, upper die radii, tonnage
(hitting harder or lighter), and the sequence of bending
are some of the things that affect blank calculations.
Adjustable Disappearing Gages provide multiple
gaging positions with complete ffexibility in vertical
and horizontal positioning. These gages are easy to
set-up, are accurate, and save many hours of work
handling. Disappearing gage stop assemblies are
located on either side of heavy duty gage bars .. Any
number of stops may be used.
CINCINNATI Standard Gage brackets without stops
can be used for work supports ..
CINCINNATI Front-operated, Dual Control Backgage
is used for gaging fight sheets. They are manually
operated and have a 24" range. Adjustment of one
screw will turn the other simultaneously.
FIGURE 31
(Continued)
BLANK DEVELOPMENT
This is not a gaging item but it is a necessary function to
determine the gage location.. Many users have developed
their own methods and calculations. Information on blank
development can be found in various handbooks ..
BEND ALLOWANCES FOR PLATE AIR BENDS
-
MILD STEEL
Tt~
)]1
j-1
I.
L
r-BJ
A
tB~
I
,
I·
BLANK WIDTH
I
-,
SIZE
BEND
PLATE
TO FIND:
DIE
RADIUS
THICKNESS
T A
B
1/4
L - 1/2
H - 1/4
2
5/16
3/8
L - 3/4 H - 3/8
3/8
l - 7/8
H - 7/16
4 5/8
1/2
l - 1
H - 1/2
3/8
l -
1-1/8
H - 9/16
6
15/16
1/2
l -
1-1/4
H - 5/8
5/8
l - 1-3/4
H - 7/8
8
1-1/4
H - 15/16
3/4
l - 1-7/8
See PRESS BRAKE CAPACITIES bulletin included with this
manual for press brake bending capacities ..
FIGURE 33
22