Bend Deductions Offsets Hems Notes

The following information has been tested by Lehi Sheet Metal
and my vary from other manufacturers.
Radius - Internal Radius
Bend Deduction-Amount subtracted per bend(coined/set bends)
Air Bend - Deduction for air bend.
K-Factor - used for engineering programs, such as Pro-E

Colled Rolled Steel - CRS

Thk Radius Bend Deduction Notes Air Bend K-Factor
.018 .030 .034     .5261
.020 .030 .039     .4417
.024 .030 .036   .047 .6599
.030 .015 .047     .4125
.030 .030 .047   .054 .5491
.030 .060 .067     .3979
.030 .187 .122     .3875
.036 .030 .054     .546
.036 .090 .085     .4532
.040 .030 .065     .4437
.040 .060 .075     .4035
.048 .030 .072   .078 .4891
.048 .060 .088     .4477
.048 .090 .101     .4460
.048 .202 .151     .4204
.060 .030 .088   .103 .4762
.060 .045 .095     .4702
.060 .060 .106     .4218
.060 .375 .232      
.060 1.000 .510     .4160
.074 .030 .112   .125 .4318
.090 .030 .131   .147 .4377
.090 .125 .172     .4361
.104 .030 .151     .4277
.120 .030 .180   .205 .3866
.134 .030 .201     .3795
.175 .030 .270      
.178 .015   3/4 DIE .280  
.187 .030 .280 1.50 DIE .318  
.187 .030 - 1.25 DIE .300  
.187 .060 .305     .3226

GALVANNEAL/GALVANIZED STEEL
Thk Radius Bend D. Comments Air Bend K-Factor
.030 .030 .051      
.036 .030 .058      
.048 .030 .076      
.048 .060 .092      
.060 .030 .092      
.060 .060 .110      
.074 .030 .116      
.090 .030 .135      
.104 .030 .155      
.120 .030 .185      
.134 .030 .205      

ALUMINUM
Thk Radius Bend D. Comments Air Bend K-Factor
.025 .030 .038     .6335
.032 .030 .049   .058 .5067
.032 .060 .068   .068 .3767
.032 .125 .094     .4170
.040 .030 .063   .065  
.050 .030 .077   .082 .4568
.062 .030 .094   .104 .4403
.062 .060 .104   .108 .4430
.062 .125 .135      
.062 .250 .190     .3958
.062 .375 .244     .3921
.062 .900 .4593     .4985
.080 .030 .122   .128  
.080 .060     .130  
.090 .030 .134   .142  
.090 .060     .151  
.090 .090 .161     .4076
.090 .125 .175     .4149
.090 .250 .242     .4393
.090 .500 .336     .4145
.100 .030 .151   .159 .3939
.100 .060     .170  
.100 .090 .172     .4408
.125 .030 .188   .200 .3813
.125 .060     .204  
.125 .125 .216     .4464
.125 .250 .266     .4650
.187 .030 .280     .3638
.187 .250 .350     .4470

STAINLESS STEEL
Thk Radius Bend D. Comments Air Bend K-Factor
.030 .030 .049   .058 .5067
.030 .060 .068   .068 .3767
.030 .125 .094     .4170
.036 .030 .058      
.048 .030 .077   .082 .4228
.048 .090 .103     .4536
.060 .030 .094  3/8" .105  
.060 .375 .244     .3921
.075 .030 .120  3/8" .129 .3639
.075 .030 - 1/2" .137 -
.090 .030 .142    152  
.105 .030 .162     .3691
.120 .030 .184   .210  

BRASS
Thk Radius Bend D. Comments Air Bend K-Factor
.016 .030 .026     .7511

 

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SPECIALS

  

ALUMINUM (SPECIALS)

Thk Radius Bend D. Comments Air Bend K-Factor
.050 .030 .040 .022 HEM O.S.   .6605
.062 .030 .075 .026 HEM O.S.   .6353

STAINLESS STEEL (SPECIALS)
Thk Radius Bend D. Comments Air Bend K-Factor
.060 .030 .075 .026 HEM O.S.   .6353
.095 .030 .156 30/60 DIES    
.095 .030 .148      
.105 .030 .180 AIRBEND   .2600
.187 .030 .346 AIRBEND 1.5 DIE    

CRS (SPECIALS)
Thk Radius Bend D. Comments Air Bend K-Factor
.036 .030 .044 .016 HEM O.S.   .7228
.048 .030 .078 AIRBEND   .4098
.060 .030 .055 1 STOCK OFFSET   .8263
.060 .030 .073 .026 HEM O.S.   .6353

OFFSETS

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CRS and Galvanneal

  
Material Offset Dies Add B.D. Approx.
Angle		 Comments
.036 .15 .187 .063 60
.036 .036 .125 .008   25  
.048 .048 .125 .010   40  
.048 .060 .125 .013   40  
.048 .150 .187 .065   64  
.048 .250 .250 .065   90  
.060 .070   .012     *Euro Tooling
.060 .100 .125 .031   67  
.060 .187 .187 .125   90  
.060 .218 .218 .155   90  
.074 .187 .187 .097   90  
.074 .190 .200 .097   83  
.074 .238 .250 .145   85  
.074 .250 .250 .162   90  
.090 .112 .187 .032   60  

Aluminum

Material Offset Dies Add B.D. Approx.
Angle		 Comments
.030 .100 .125 .045   65  
.062 .160 .187 .076   80  
.062 .190 .187 .107   90  
.062 .250 .250 .180   90  
.090 .187 .250 .070   60  

Stainless Steel

Material Offset Dies Add B.D. Approx.
Angle		 Comments
.075 .500 .500 .392   90  

HEMS

Material Gap Add Subtract Comments
.036 .070 .013    
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NOTES

Tonnage Formula

Material Toyokoki (125 tons)

Formula

 Comments
ALUM

stock thickness   x

 600

=  Tons/ft

  
CRS

stock thickness   x

 650

=  Tons/ft

  
St. Stl.

stock thickness   x

 900

=  Tons/ft

  

Material Mechanical (150 tons)

Formula

 Comments
ALUM

stock thickness   x

 300

=  Tons/ft

  
CRS

stock thickness   x

 350

=  Tons/ft

  
St. Stl.

stock thickness   x

 400

=  Tons/ft

  

Minimum 1/2 Shear bending

Thickness "A"

Bottom Die

 Comments
.048 .247 1/4

 
.060 .284 1/4

 
.060 .324 5/16

 
.074 .425 3/8

 
.090 .435 3/8

 

 
Bend Deductions
Tap Sizes
Material Gauges
Pem Chart
Drill Sizes
Screw Details
   
   
Lehi Sheet Metal, Corp.
info@lehisheetmetal.com
245 Flanders Rd. Westboro, MA 01602 Phone (508) 366-8550 fax(508) 870-1714