Lead Came Stained Glass Pattern

One reference square, three real offsets

H-section and U-section came describe different edge roles

An H-shaped came section has a central heart with a channel on either side. Neighboring glass pieces sit on opposite sides of that heart. A U-shaped perimeter section receives glass on one side and closes the outside edge. The face width visible over the glass is separate from the heart thickness between pieces. A broad visible lead line does not tell you that the center gap should be equally broad.

The workshop provides 1.6 and 2.0 mm heart settings. They create 0.8 and 1.0 mm inward offsets respectively on each glass piece. The black, copper and silver-grey preview choices are visual finishes and do not substitute for selecting a physical heart. Check the came you intend to use and the fit of a measured sample; the preset is a numeric allowance for a planar drawing, not a catalog promise about every real profile.

Compare the same reference piece across constructions

A 100 × 100 mm centerline square becomes 98.4 × 98.4 mm with the 1.6 mm heart. Its area is 9682.56 mm², or 96.8256 cm². With a 2.0 mm heart, each side becomes 98.0 mm and the area is 9604 mm², or 96.04 cm². Both results account for the two opposing offsets; subtracting half the heart only once from the overall side would give the wrong glass size.

For comparison, the copper foil setting leaves a 99.2 mm square and 98.4064 cm². The 2.0 mm came setting therefore uses 2.3664 cm² less glass on that one reference block. In an irregular drawing, that difference depends on the actual perimeter and corners of every piece. The material list integrates each offset polygon instead of multiplying one square example by a count of unrelated shapes.

Keep outside panel size separate from cut glass

A 16 × 20 inch panel is 406.4 × 508 mm because one inch equals exactly 25.4 mm. Those are the intended centerline drawing dimensions. Selecting a wider heart changes the individual cutting contours and net glass area, while keeping the overall centerline panel size. It should not silently scale the entire panel down or change the printable grid to compensate for a different seam.

A perimeter U channel, a zinc frame, and the opening into which the panel will fit introduce additional real measurements. Decide whether your stated panel dimension refers to the cartoon, the finished frame outside, or the clear opening. Measure the actual perimeter profiles and frame engagement before final cutting. The tool does not infer a structural frame allowance from the color of the preview seam or automatically certify an installation from width and height.

Avoid accumulated measurement errors

Consider five nominal 100 mm pieces arranged across a row. If each is mistakenly cut to 100 mm rather than the 98 mm contour selected for a 2.0 mm heart, every piece carries extra material relative to its intended cutting template. The joint and boundary treatment still need their own fit checks; the practical point is that errors repeat across a row. A near-correct single piece does not prove a whole assembled row will fit.

Use a fixed millimetre geometry snapshot and compare several neighboring numbers before committing to a long row. Changing the display to inches should convert values while keeping the same internal coordinates. Changing construction should recalculate the cuts while keeping the same centerlines. Those two actions have different effects and are both visible in the selected-piece inspector. A local project file preserves the settings so you can reopen the same reference later.

Review corners and thin necks after compensation

The 6–20 mm minimum-width threshold is a geometric review aid. It detects narrow strips and interior necks in the centerline pieces, then the cutting file applies the chosen inset. A larger came heart can remove more usable glass from an already narrow region. If the compensated contour collapses, disappears or crosses itself, the tool reports its piece number and prevents a misleading cutting export.

Deep inward corners deserve separate review. An H profile does not make a U-shaped glass piece easy to break from a sheet. A merge may eliminate a thin strip while creating another concavity, so inspect the updated report and outline together. Use grinding or a different split where appropriate, and keep the remaining risks visible. These calculations describe planar geometry and do not predict stresses, reinforcing requirements or the durability of a finished panel.

Move from a checked cartoon to workshop files

Use the free centerline DXF for the unshrunk cartoon and the free single-layer inset SVG for cutting outlines. The two names distinguish their roles. For a paper plan, choose A4 or Letter, set printable margins and overlap, and print the free tiled PDF at 100%. The 100 mm and 4 inch calibration marks give you a physical check that cannot be replaced by the zoom percentage shown in a browser preview.

The paid compensated pack contains millimetre CAD layers by color and piece number, closed LWPOLYLINE contours, sticker-die weeding and registration references, and a geometry manifest. Compare their coordinates and bounds with the selected construction. If you also need stock planning, the separate nesting pack groups pieces by glass color and honors the requested grain rotation. Area plus a waste percentage remains a material estimate; it is not a substitute for fitting the pieces onto a real stock rectangle.