Metalworking Calculators

Bend Allowance Calculator

Calculate sheet metal bend allowance and bend deduction from bend angle, inside radius, thickness, and K-factor, with fully worked flat-pattern examples.

Feed Rate Calculator

Calculate CNC feed rate for milling from RPM, flute count, and chip load, or for turning and drilling from RPM and feed per revolution, with worked examples.

Kerf Width Calculator

Calculate how many parts a length of stock yields once cutting kerf is accounted for, with worked examples showing material lost to each cut.

Metal Cutting Speed Calculator

Convert between cutting speed (SFM) and spindle RPM for turning operations using workpiece diameter, with worked examples for common materials.

Metal Sheet Gauge Calculator

Convert between Manufacturers' Standard Gauge numbers and actual thickness for steel sheet in both inches and millimeters, with the full reference table.

Metal Weight Per Foot Calculator

Calculate weight per foot for round, square, rectangular bar, and round tube stock across common metals, with worked examples by shape and material.

Press Brake Tonnage Calculator

Estimate press brake tonnage needed for a bend from length, thickness, die opening, and material, with worked examples comparing steel and stainless.

Sheet Metal Weight Calculator

Calculate sheet metal weight from length, width, thickness, and material density, covering steel, aluminum, titanium and other common metals.

Tap Drill Size Calculator

Calculate the correct tap drill size for imperial or metric threads from major diameter and TPI or pitch, with worked examples for common thread sizes.

Welding Cost Calculator

Calculate total welding job cost from weld length, speed, labor rate, consumables, gas, and overhead, with a full worked cost breakdown example.

The Numbers a Metal Shop Checks Before Cutting or Bending

Metal fabrication has little tolerance for guesswork — a bend allowance calculated wrong throws off a part's final flat-pattern dimensions, an incorrect tap drill size strips threads before they're even cut, and the wrong feed rate either burns a cutting tool early or leaves a poor finish. Ten calculators here cover the shop-floor formulas used in cutting, bending, and joining metal.

Popular Metalworking Calculators

Ten tools span cutting, bending, and joining:

  • Bend Allowance Calculator — calculates the flat-pattern length needed to achieve a target bent dimension, accounting for material thickness and bend radius.
  • Sheet Metal Weight Calculator — converts sheet dimensions and material density into total weight for handling and shipping.
  • Tap Drill Size Calculator — finds the correct pilot hole size for a given thread size and desired thread engagement percentage.
  • Metal Cutting Speed Calculator — calculates spindle speed from material type, tool diameter, and recommended surface speed.
  • Welding Cost Calculator — estimates total welding job cost from material, filler, labor, and shop rate.

Why Bend Allowance Isn't Just Simple Geometry

Metal doesn't bend at a single sharp line the way a flat-pattern drawing implies — it stretches on the outside of the bend and compresses on the inside, with a neutral axis somewhere in between that shifts based on material thickness and bend radius. Bend allowance calculations account for that neutral axis shift precisely because using the simple outer or inner dimension alone would produce a part that comes out the wrong final size once bent, which is a frustrating and expensive mistake to discover after cutting an entire batch of flat blanks.

Frequently Asked Questions

Why does tap drill size depend on thread engagement percentage, not just thread size?
A pilot hole sized for 100% thread engagement is often unnecessarily hard to tap and more prone to breaking taps; most applications use 65–75% engagement, which requires a specific, slightly larger drill size than a 100% engagement calculation would suggest.

Does cutting speed change with tool material, not just workpiece material?
Yes — carbide tooling tolerates much higher cutting speeds than high-speed steel for the same workpiece material, so recommended speed depends on both sides of the cutting interface.

Explore More

Working with wood instead of metal? See the Woodworking Calculators, or check broader manufacturing efficiency metrics in the Manufacturing Calculators.