Contractor Job Estimator
Price remodels and GC work, then send a quote with no internal numbers.
Excel or Google Sheets. Best on a computer.
$29.00
BuyCone / Transition Flat-Pattern Troubleshooting
Printer scaling · height vs slant · throat closure · seam shortfall
Diagnose templates that won’t roll true, mixed-up height inputs, lobster-back throat closure, and blanks that come up short without seam allowance.
Fix the template, then re-print
Most “won’t roll true” failures are printer scaling — measure the reference square before blaming the math.
Open the Generator →Template Doesn’t Roll True
Likely cause: The PDF was scaled by the printer (“Fit to page” / “Shrink to fit”). The reference square on page 1 must measure exactly 1 in or 50 mm. If it doesn’t, every radius and arc is wrong. Re-print at 100% / Actual Size, verify the square, then cut.
Height vs Slant Height — Easy Mix-Up
Vertical height is the standing height of the cone/frustum. Slant height is the distance along the side from apex (or between ends on a frustum). Entering one when you meant the other changes L and θ and the blank will be the wrong size even though the preview “looks fine.” Check which toggle is active under “Specify by,” and open Show the math to confirm.
Lobster-Back Throat Closing Up
If centerline bend radius is too close to the pipe radius, the inside (throat) of the elbow collapses toward zero width. Increase CLR (long-radius elbows are often ~1.5× diameter) or reduce segment angle / change gore count. The tool requires bend radius > pipe radius so the throat stays open.
Forgot Seam Allowance — Came Up Short
The exported pattern is finished surface only. If you cut on the line and then try to lock-seam or lap without extra stock, the joined circumference comes up short. Add allowance before cutting — see seam allowance by joining method.
Thick Plate vs Thin-Material Assumption
Development is taken at one surface. On thick plate, decide whether diameters are ID, OD, or mean, and expect a neutral-axis correction the flat pattern does not apply. Dry-fit and adjust before final weld — same discipline as the Tube Notch Troubleshooting guide for thick-wall tube.
More Help
Walk through each mode in the Cone / Transition Flat-Pattern Guide. For related sheet work, see the Sheet Metal Bending Guide and Sheet Metal Gauge Chart.
Any trade
Checkout opens in a new tab.
Recommended Sheet Metal Layout & Cutting Tools
Cut the developed pattern, then form and join — products from the TestTalkHQ affiliate catalog
Malco M2006 10" Left Offset Snips
- Offset left-cut for long pattern edges
- Keeps hands clear of the sheet
- Shop standard for sheet-metal layout cuts
- Pairs with right-cut snips for curves
Malco AV73 Right Offset Snips
- Long-cut right offset for arcs
- Follow outer/inner sector edges
- Aviation-style compound leverage
- Complement to left-offset snips
Malco TS1 TurboShear Attachment
- Drill-powered shear for long cuts
- Faster than hand snips on large blanks
- Useful after tracing the PDF template
- 20-gauge sheet metal capacity class
Klein Tools 86528 Sheet Metal Punch Set
- Snap-lock and hole punch set
- Useful near seam edges for fasteners
- HVAC / duct fab staple
- Pairs with riveted transitions
Neiko Auto Body Hammer & Dolly Kit
- Hand-form cones and gores after cutting
- Dolly support for rolling thin sheet
- Useful for lobster-back dry-fit tweaks
- Shop fab companion to snips
Catalog gaps: No hand seamer / seamers, rivet gun, or sheet-metal brake products exist in the TestTalkHQ affiliate CSV at publish time — we do not substitute unrelated electrical or welding gear for those roles.
As an Amazon Associate, TestTalkHQ earns from qualifying purchases.