Automatic creation of sheet metal parts; ... Automatic unfolding with or without bending technology (Calculation of the shortening factor or K-factor) Although you may find several different formulas that claim to calculate the Bend Allowance (See Bending Definitions), they usually are the same formula, only simplified by filling in the angle or a K-factor. Oh, and yes, you do need to know the K-factor to calculate the Bend Allowance. Let’s start with a simple L bracket. Sep 08, 2011 · One of our customers recently asked us how they could display the k-factor for a sheet-metal part on a drawing. This is not as easy as pulling a parameter through to the drawing as the k-factor value is embedded in the sheet-metal style of the component. Calculator Notes and Assumptions. Calculator is based on Chapter 1 of SMACNA's Architectural Sheet Metal Manual 7th Edition (ASMM). Rainfall Wizard is based on Table 1-2 Rainfall Data and Drainage Factors, Page 1.2-1.3 of the Architectural Sheet Metal Manual 7th Edition. K-FACTOR CALCULATOR - automatically calculates the correct k-factor for the chosen thickness and bend radius. K-factor can also be entered manually. Developed by a professional engineer with 13 years experience in the metal forming industry. Re: K Factor - Sheet Metal Works Basically, you have three factors to consider when using K factor, thickness, bend rad and fold allowance, when one of these is missing, K Factor calculator will work it out.