Kismet CNC Fabrication Tips · Lesson 5 of 12
That little strip of metal connecting the center of a letter to the rest of a sign? That's a bridge. Without it, anything completely surrounded by a cut becomes an island that falls out.
Think of bridges as structure
Look at the center of a stencil-style A, O or R. If it's surrounded by one uninterrupted opening, it won't be attached to the finished sign. A bridge connects it back to the metal you're keeping. The same applies to animal silhouettes, branches and decorative panels.
Make the bridge fit the artwork rather than sticking an ugly block wherever it happens to fit. More importantly, don't sacrifice strength just to make the screen preview pretty.
How narrow is too narrow?
There's no single safe minimum for every cutter. Material thickness, actual kerf, heat, nearby cuts, process settings and the shape of the connection all affect what survives.
Kismet's current general design standard is .165" minimum for bridges where we don't control a customer's cutting setup. That's our shop standard, not a rule that every plasma cutter needs .165". An individual cutter and material combination can have different practical limits.
Does kerf automatically eat the whole bridge?
Not when the toolpath is set correctly. Inside Offset and Outside Offset place the kerf in the scrap, so you shouldn't automatically subtract the full kerf width from every bridge in a compensated design.
That doesn't make a narrow connection indestructible. Cut bevel, heat, handling and cleaning still matter. A bridge that survives the cut may not survive the next step.
Measure the design at its finished size
Zoom in and measure the narrowest point of every critical connection. Resize the design and measure again: a .165" bridge becomes .0825" when the artwork is scaled to 50%.
Check adjacent openings, too. A sturdy bridge won't save a cut if the torch has nowhere sensible to pierce or enter. That's what we'll tackle next.
Previous: Inside, Outside, or No Offset? Which One Should You Choose? ←
Coming next: Lead-Ins and Lead-Outs in CNC Plasma Cutting. Lesson 6 will be linked here when published.