Process
End forming
A wire form is a centerline plus ends. Chamfer, coin, flatten, pierce, swage, and thread are how 4–14 mm wire actually installs — not decoration on the CAD solid.
What end forming is
End forming changes the last few diameters of the wire so it can enter a hole, take a screw, weld to a plate, or stop against a shoulder. It is a secondary to 2D and 3D CNC, and it is often the reason a “simple bend” is not simple.
In-line end work on the CNC cell is fastest when the op is a chamfer or a light coin. Dedicated presses, pointing dies, and thread rollers show up when the end is the product: a flattened weld tab, a pierced eye, a rolled thread.
The operations
- Chamfer / point — lead-in for insertion. Call the included angle and the remaining face diameter.
- Coin / flatten — a paddle for a weld, a rivet, or a stamped mark. Thickness and width after coin, not “flatten end.”
- Pierce — a hole through a flattened end or through the round. Edge distance matters; 4 mm wire has little of it.
- Swage / reduce — diameter down so the end enters a tube or a smaller hole. Length of reduction and blend radius.
- Thread — roll or cut. Roll is stronger on mild carbon; cut is more common when the end was already coined. Spec the thread, class, and usable length.
- Loop / eye — a closed or open eye as the end. Inside diameter, gap, and whether a weld is allowed. Fully closed eyes can trap on CNC tooling — see the design guide.
What changes from 4 to 14 mm
| Diameter | Inch | End work |
|---|---|---|
| 4 mm | 0.157 in | Chamfer and light coin in-line. Pierced eyes need a real flatten first. |
| 8 mm | 0.315 in | Flattened weld tabs are common. Thread rolls need a straight behind the thread. |
| 12 mm | 0.472 in | Swage and heavy coin want a press, not a hope on the CNC head. |
| 14 mm | 0.551 in | Ends are structural. Call face, thickness, and weld prep. Do not imply a clip-style dime flatten. |
Print callouts that get quoted
- Which end (or both), and a datum from the mating part
- Before/after dimensions on flatten and swage
- Thread spec and incomplete-thread allowance
- Burr and coating: pre-coated wire will crack at a tight coin
- Whether the end is formed before or after plating
A STEP of the bent solid with a sharp cutoff is not an end spec. If the end mates, draw the end.
Related
- Cut-to-length
- Resistance welding — coined tabs often exist to be welded
- Plating and coating