Hole-to-Bend Distance Calculator
Holes too close to a bend distort when the part forms — the deformation zone extends past the bend radius. Enter thickness and inside radius and this returns the minimum clearance from a hole edge to the bend line (≈ 2.5 × t + R) and the working minimum from a hole to a part edge (≈ 1 × t). Design rules of thumb, not guarantees: the die, the grain and the alloy all move the real number.
Measured from the hole edge to the bend line (2.5 × t + R). Inside that zone the metal stretches during forming and round holes go oval. If the design cannot move the hole, the fixes are a slot, a relief cut, or drilling after bending — in that order of cost. Full rules:
Questions about hole-to-bend clearance
Air-bending rule of thumb: hole edge to bend line ≈ 2.5 × t + R; the same rule the DFM review applies.
Why 2.5 × t + R from the hole edge?
The deformation zone of a bend extends past the radius, and anything inside it stretches: round holes go oval and slots elongate. The 2.5-thickness rule plus the inside radius clears the hole edge out of that zone with margin for typical air bending.
My hole is closer than that. Is the part scrap?
No — it means the hole moves after forming or gets made after forming. Options in order of cost: a slot that absorbs the stretch, a relief cut at the bend, or drilling the hole after bending. Each is quoted differently, which is why the DFM review raises it before the order.
Does the alloy change the clearance?
Slightly. Softer alloys stretch further before tearing, so the rule holds with more margin; high-strength alloys and large radii push the deformation zone wider. For a part with multiple close features, send the drawing — the review measures it against the actual die.
Keep going
Calculators — enter dimensions, get a number
Sheet Metal Weight CalculatorWeight per piece and per batch from L × W × t, with real alloy densities.Bend Allowance CalculatorThe neutral-axis length through a bend, from thickness, radius, angle and K-factor.Sheet Metal Cost CalculatorWhere a part’s cost actually sits — material, cutting, forming, finishing and setup.Press Brake Tonnage CalculatorBending force in kN and tons from thickness, material and bend length, with a 20% margin.K-Factor Calculator (Reverse)Reverse a K-factor from a real bend: outside dimensions and flat length in, K out.Charts and checklists — read, print, work through
Sheet Metal Gauge to mm ChartSteel (MSG) and aluminium (B&S) gauge dimensions, and why we quote in mm.Sheet Metal DFM ChecklistThe 24 checks we run on a drawing before we quote it, grouped and explained.Sheet Metal RFQ ChecklistThe 12 items that make an RFQ quotable in one round, with the reason each matters.Sheet Metal Supplier Audit Checklist13 remote-verifiable checks for a sheet metal supplier, in four passes.Close features flagged before the order
Holes near bends, tight flanges, thin webs — the DFM review measures every clearance against the actual die and returns the fixes ranked by cost, free with every quote.
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