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BuyFlat-Pattern Unfolder vs Single-Bend Calculators — Which to Use
Size one bend, then chain the whole part — a sequential workflow
The single-bend Bend Allowance and Bend Deduction calculators size one bend; the Flat-Pattern Unfolder chains multiple bends into a complete flat blank. A clear explainer of their complementary, sequential roles — not real alternatives.
Sequential workflow — not real alternatives
The single-bend calculators size one bend; this builder chains multiple bends into a complete flat pattern.
Bend Allowance Calculator → Bend Deduction Calculator → Flat-Pattern Unfolder →These Are Not Competing Tools
It is tempting to ask "which should I use — the bend allowance calculator or the unfolder?" But that framing is wrong: they are not alternatives, they are steps in one workflow. The single-bend calculators answer a focused question about one bend. The unfolder assembles many bends into a finished blank. You typically use both, in order.
What the Single-Bend Calculators Do
The Sheet Metal Bend Allowance Calculator computes the bend allowance — the neutral-axis arc length — for one bend from thickness, inside radius, K-factor, and angle. The Sheet Metal Bend Deduction Calculator computes the bend deduction for one bend, i.e. how much shorter the flat is than the summed outside/mold-line dimensions. Use these when you want to understand or verify a single bend's numbers, check a value from a chart, or size one isolated feature.
What the Flat-Pattern Unfolder Does
The Bend Allowance / Flat-Pattern Unfolder takes a whole part — a chain of legs and bends — and produces the complete flat blank: total developed length, a to-scale flat pattern with every bend line placed, a side-profile schematic, and a per-bend breakdown. It applies the same BA/BD math as the single-bend calculators, but at every bend in the sequence at once, and it exports the result as PDF, DXF, CSV, or JSON. This is what you need to actually cut and form a U-channel, hat section, box, or bracket.
How They Work Together
A typical sequence: use the single-bend Bend Allowance or Bend Deduction calculator to confirm the numbers and your K-factor for one representative bend → open the Flat-Pattern Unfolder and enter the full leg-and-bend sequence with that verified K → export the flat-pattern PDF and DXF and cut the blank. The single-bend calculators build your confidence in the inputs; the unfolder turns those inputs into a manufacturable layout. They are complementary, and the guide shows the full path end to end.
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Recommended Bend Layout & Measuring Tools
Verify bend angles, transfer flat-pattern marks, and cut the blank — products from the TestTalkHQ affiliate catalog.
Klein Tools 935DGGP Digital Angle Gauge
- Confirm bend and included angles on formed parts
- Magnetic base sits on the flange or brake bed
- Check your assumed bend angle against the tool
- Zero/relative modes for reference-face reads
Starrett Electronic Slide Caliper (0–6")
- Measure material thickness for the K-factor model
- Read leg and flange lengths precisely
- Inch/mm switch matches either unit mode
- Verify flat-blank cuts before forming
Malco M2006 10" Left Offset Snips
- Offset left-cut for long flat-pattern edges
- Keeps hands clear of the sheet
- Shop standard for sheet-metal layout cuts
- Pairs with right-cut snips for corners
Malco AV73 Right Offset Snips
- Long-cut right offset for the opposite hand
- Follow the outline of the unfolded blank
- Aviation-style compound leverage
- Complement to the left-offset snips
Malco TS1 TurboShear Attachment
- Drill-powered shear for long blank cuts
- Faster than hand snips on large flats
- Useful after transferring the PDF layout
- 20-gauge sheet metal capacity class
Catalog gaps: No sheet-metal brake / press-brake products, and no bend-allowance reference charts or books, exist in the TestTalkHQ affiliate CSV at publish time — we do not substitute unrelated electrical conduit benders for those roles.
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