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Insert Hole / Shaft Fit

In one sentence: Places an ISO 286 hole-and-shaft tolerance annotation (e.g. H7/g6) on a dimension or view, with optional deviation values.

Overview

Workbench: TechDraw
Menu: TechDraw → Symbols → Insert Hole / Shaft Fit

The annotation shows the tolerance designation and optionally the calculated upper and lower deviations based on the nominal diameter and grade.

ISO tolerance system basics

ISO 286 defines fits using: - A fundamental deviation letter — uppercase for holes (A–ZC), lowercase for shafts (a–zc) - An IT grade number (1–18) — lower numbers are tighter

Common fits:

Designation Type Example use
H7/g6 Clearance fit Sliding bearing
H7/k6 Transition fit Gear on shaft
H7/p6 Interference fit Press fit

Step-by-step

  1. Select a dimension (e.g. Diameter Dimension on a hole) or a view.
  2. Choose TechDraw → Symbols → Insert Hole / Shaft Fit.
  3. In the task panel:
  4. Select the Hole Tolerance (e.g. H7).
  5. Select the Shaft Tolerance (e.g. g6).
  6. Choose display format: symbol only, deviations only, or both.
  7. Click OK.

Common mistakes and pitfalls

Tolerance deviations require correct nominal diameter

The deviation values (computed in μm) depend on the nominal size. If the nominal diameter on the drawing is wrong, the computed deviations will also be wrong. Verify the nominal dimension before applying the fit annotation.

See also