STOCKED PRESS BRAKE DIES - Precision Tooling and Die Types - Air Bend, Bottoming, Flattening, Fourway

Oct 23, 2026

STOCKED PRESS BRAKE DIES provides precision tooling guidance for press brake forming, detailing die length code ranges, die tongue dimensions, and how radius, included angles, and capacity apply to mild steel. It explains air bend control and compensation for springback using included angles (often 75° or less) and ram reversal models such as AUTOFORM. It further covers bottoming dies for accurate bends with sharp inside radii, flattening and hemming use cases, and fourway dies for frequent jobbing die opening changes. Safety and gaging setups are included to support proper bending sequence.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages8

Reading Time20 min

AccessFree to download

STOCKED PRESS BRAKE DIES

Die Length Codes

AIR BEND DIES

BOTTOMING DIES

FLATTENING DIES

FOURWAY DIES

CINCINNATI

CINCINNATI Stocked Press Brake Gaging

KEEP SAFETY IN MIND

Pl-82001CINCINNATI # STOCKED PRESS BRAKE DIES Increase Your Profitswith Precision Tooling ## CINCINNATlStocked Press Brake Dies DIE LENGTH CODES | B | D | F | H | K | M | P | R | | --- | --- | --- | --- | --- | --- | --- | --- | | (25 | 49”
(41”) | 73”
(6'1”) | 97”
(8'1") | (102) | 146”
(12'2”) | 170”
(142”) | 194”
(16'2” | All tongues are 5/g"high×V2"wide."R"equals radius of noseof upper die and should not be confused with inside radiusof angle formed by die.Capacity shown is for mild steel. All ncluded angles 85°unless otherwise specified ### AIR BEND DIES Included angle for both upper and lower dies allows for overbending of metal tocompensate for springback,Angles from very shallow to 90°are formed byadjusting the press brake ram. If parts are to be formed with "air bend"dies on a press brake with controls thatuse mathematical models (i.e.AUTOFORM⑧)to determine ram reversalpositions,the dies must be cut to a 75 degree or less angle to compensate forall possible material springback.In some cases,30 degree dies can beselected to obtain true air bending of 90 degree angles. Copyright 1989 Cincinnati Incorporated All included angles 30° Acute angle dies are used for air bends from very shallow angles to 30 degreeangles.The angle formed depends on the depth to which the upper die entersthe lower die.Acute angle dies are commonly used to preform hems. R=1/64” S1F02 S1F08 R=1/8” S1C08 R=1/32”R=1/8” S1A02 SIE12 R=1/8” R=1/32” S1F04 S1F12 R=3/16” R=3/16” S¹C12R=3/16” R=1/16” S1A04 R=1/16” S2B03 S2B04 S2B05 S2D05 S2D08 S2B02 S2D06 S2D07 11 ga.max. 18 ga.max. 16 ga.max. 14 ga.max. 14 ga.max. 22 ga.max. 13 ga.max. 12 ga.max. All included angles 90° ### BOTTOMING DIES Bottoming dies are used for making very accurate bends with relativelysharp inside radii in comparatively light gauge material,such as 12 gaugeand thinner.Included angle is 90 degree for both upper and lower dies. S5E02S5E03S5E04S5E05S4B0122 ga.18 ga.16 ga.14 ga. R=1/64”max.max.max.max.S4B02S4C01S4E04R=1/32”R=1/64”R=1/16”S4A01S4B04S4E06R=1/64”S4F01R=1/16”R=1/32”R=3/32”S4A02R=1/64”S4B06S4C04S4E08R=1/32”S4F02R=3/32"R=1/16”R=1/8”S4A04R=1/32”S4C06R=1/16”R=3/32"R=1/16” |1-1/8|S5D09S5D12S5D16S5B02S5B03S5B04S5B05S5B06S5C07S5C0810 ga.max.3/16”max.1/4”max.22 ga.18 ga.16 ga.14 ga.13 ga.12 ga.11 ga.max.max.max.max.max.max.max. All included angles 85° S8C8AR=1/8” S8D06R=3/32” S8D08 R=1/8” 1/4"max. 3/8”max. ### FLATTENING DIES Flattening dies are used for "hemming"or flatteningacute angle bends.Flattening dies and acute angledies mounted side by side in a press brake canproduce a hem with each press brake stroke. Gooseneck dies are used for making channels or special shapes with which a straight sided diewould interfere.Deeper "throat"beyond the die centerline increases width of return flange butreduces die capacity.Interference can be checked using a gooseneck die template which canbe requested from CINCINNATI. All included angles 90° Included angle 30° 16 ga.max. S1CR2 S8C4BR=1/16” R=1/32” 14 ga.max. 10 ga.max. S1CR4 S8D12 R=3/16” R=1/16” 3/8"max.3/8"max. 14 ga.max. If parts are to be formed with "air bend"dies on a press brake with controls thatuse mathematical models (i.e.AUTOFORM⑧)to determine ram reversalpositions,the dies must be cut to a 75 degree or less angle to compensate forall possible material springback.In some cases,30 degree dies can beselected to obtain true air bending of 90 degree angles. ## FOURWAY DIES All vees 85°unless otherwise specified Fourway dies are useful for jobbing work wherechanges in die opening are frequently desired. 11-12-4 S20B3 S20C3 S20D5 ## CINCINNATI Also available is a wide selection of bar sizes,maintained in our inventory,which can be modified to your specific needs.Reference diesetidentification numbers shown when

FAQs

How are die length codes and tongue dimensions defined?

Die length codes are listed across lettered columns, and the tongue dimensions are given as 5/8" high by 1/2" wide. The document also notes how R is defined for the nose radius of the upper die.

What determines air bending die angles on a press brake?

Air bend use requires included angles for overbending to compensate for springback. With controls using mathematical models (e.g., AUTOFORM), dies must be cut to 75° or less to address all possible material springback.

When should bottoming dies be used?

Bottoming dies are for highly accurate bends in comparatively light gauge material, with relatively sharp inside radii. The document states included angles are 90° for both upper and lower dies.

Oct 23, 2026

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