Workholding is how the part is secured while it’s machined, and it matters as much as the tool — a part that shifts or vibrates ruins finish and accuracy and can be dangerous. The goal is to hold the part rigidly, repeatably, and without distortion.
Common methods
- Machine vise — the workhorse for prismatic parts; fast and rigid. Soft jaws can be machined to grip odd shapes.
- Clamps / strap clamps — bolt the part to the table for large or irregular pieces; keep clamping force near supports.
- Fixtures — custom holders for production, locating the part the same way every time.
- Specialty — collet blocks, chucks, vacuum tables, magnetic chucks for specific jobs.
Principles
Clamp against solid support so force doesn’t bend the part, hold on the most rigid features, and keep clamps clear of the toolpath. For thin or delicate parts, spread the clamping force to avoid distortion. Repeatability — putting each part in the same place — is what makes a run of parts consistent.
Frequently asked questions
Most common workholding? A machine vise, often with soft jaws for shaped parts.
How do I avoid distorting a part? Clamp against support and spread the force; don’t over-tighten thin sections.
Why are fixtures used? For repeatable, fast loading in production.