Five sheet metal details that quietly change your quote
Sheet metal looks simple — cut, fold, done. Most of the cost lives in details that are easy to miss on the drawing and hard to unsee once you know them.
1. Holes too close to bends
When a sheet folds, the material near the bend stretches. A hole sitting inside that zone distorts into something oval-ish, and a fastener will notice. The usual rule of thumb: keep holes at least two to three material thicknesses away from the start of the bend.
When a hole must be near the bend, it gets cut after forming, or slotted to absorb the distortion — either way, an extra decision and often an extra operation. Move the hole if the design allows it; flag it if it doesn't.
2. One bend radius per part
Every bend radius on a press brake corresponds to tooling. Three different radii on one part can mean three tool setups on a part that needed one. Unless the function demands otherwise, pick a single radius — ideally roughly equal to the material thickness — and use it everywhere.
3. The weld symbol you didn't mean
A continuous weld with a ground-flush finish can cost more than every other operation on the part combined — welding, then grinding, then dealing with the distortion that heat put in. Sometimes the part truly needs it: a sealed tank, a cosmetic corner. Often, a stitch weld or a folded corner does the same job for a fraction of the cost.
Ask of every weld symbol: does this joint need to be sealed, strong, or pretty? Specify only the ones that are true.
4. Countersinks and forms in thin material
A countersink for an M4 flat-head screw needs enough material to live in. In thin sheet, there isn't enough — the countersink breaks through and holds nothing. The fabricated answer is usually different from the machined one: a dimpled hole, a press-in fastener, or simply a button-head screw. If you're specifying flat-head hardware on sheet parts, this conversation is coming; having it at RFQ time is free.
5. Tolerances written for machining
Folded parts accumulate variation bend by bend — flatness, angle, and hole-to-edge dimensions across a bend all behave differently from a machined block. A ±0.05 mm callout across two bends doesn't make the press brake more accurate; it makes the part a candidate for machining after forming, at machining prices.
Put the tight tolerances on features cut in the flat (hole patterns, edges), keep post-bend expectations realistic, and the quote stays a sheet metal quote.
The pattern behind all five
None of these are design mistakes — they're places where the drawing quietly commits the part to extra operations. The fix is rarely "change the design"; it's usually "say what you actually need." A good fabricator reads the drawing looking for exactly these five things, and asks. A good RFQ answers before the question is sent.
Have a sheet part on the screen right now? Send it through the quote form — if any of these five show up on your drawing, the reply will say so, along with what each one is costing you.