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Casting tolerance reference (ISO 8062-3)

Enter a nominal dimension and select a dimensional casting tolerance grade to see the total tolerance from the standard's table.

Lookup

Method, assumptions and limitations

Direct table lookup of the linear dimensional casting tolerance (DCT) for the size range containing the nominal dimension, per ISO 8062-3 (edition 2023). No interpolation is performed. The tool covers grades DCTG 4 to 8 up to 400 mm; it does not cover wall thicknesses (for which the standard applies a coarser grade), geometrical tolerances, VDG P 690 accuracy grades or any supplier capability. Which grade is achievable for a given feature must be agreed with the foundry.

Reference table

Nominal dimension (mm)DCTG 4DCTG 5DCTG 6DCTG 7DCTG 8
> 0 – 100.260.360.520.741.00
> 10 – 160.280.380.540.781.10
> 16 – 250.300.420.580.821.20
> 25 – 400.320.460.640.901.30
> 40 – 630.360.500.701.001.40
> 63 – 1000.400.560.781.101.60
> 100 – 1600.440.620.881.201.80
> 160 – 2500.500.701.001.402.00
> 250 – 4000.560.781.101.602.20

Total linear dimensional casting tolerance (DCT) in mm for grades DCTG 4 to 8 and nominal dimensions up to 400 mm, as tabulated in ISO 8062-3. The tolerance zone is normally placed symmetrically about the nominal dimension. Extract for orientation; the standard itself is authoritative and contains further grades, sizes, wall-thickness rules and geometrical tolerances.

Which grade?

The achievable grade depends on the alloy, the size and geometry of the part, whether the dimension is restrained by the shell, and the production quantity. For investment castings, grades around DCTG 4 to 6 are commonly quoted for general dimensions. A finer grade for selected dimensions is possible by agreement and usually requires die correction after first samples. The background is explained on the tolerances page.

VDG P 690

Linear casting tolerances (± mm) — Material group D: alloys based on iron, nickel, cobalt and copper

Nominal dimension (mm)D1D2D3
≤ 60.150.120.10
> 6 – 100.180.140.11
> 10 – 180.220.170.14
> 18 – 300.260.200.17
> 30 – 500.400.310.25
> 50 – 800.450.370.30
> 80 – 1200.550.440.35
> 120 – 1800.800.650.50
> 180 – 2501.200.950.75
> 250 – 3151.301.100.80
> 315 – 4001.801.40—

Linear casting tolerances (± mm) — Material group A: alloys based on aluminium and magnesium

Nominal dimension (mm)A1A2A3
≤ 60.150.120.10
> 6 – 100.180.140.11
> 10 – 180.220.170.14
> 18 – 300.260.200.17
> 30 – 500.400.310.25
> 50 – 800.450.370.30
> 80 – 1200.550.440.35
> 120 – 1800.800.650.50
> 180 – 2500.950.750.60
> 250 – 3151.301.100.80
> 315 – 4001.401.200.85
> 400 – 5001.601.300.95
> 500 – 6302.201.70—
> 630 – 8002.502.00—
> 800 – 10002.802.30—
> 1000 – 12503.30——

Linear casting tolerances (± mm) — Material group T: alloys based on titanium

Nominal dimension (mm)T1T2T3
≤ 60.250.200.20
> 6 – 100.300.200.20
> 10 – 180.350.250.22
> 18 – 300.400.350.26
> 30 – 500.500.400.31
> 50 – 800.750.600.45
> 80 – 1200.850.700.55
> 120 – 1801.000.800.65
> 180 – 2501.200.950.75
> 250 – 3151.601.30—
> 315 – 4001.801.40—
> 400 – 5002.001.60—
> 500 – 6302.702.20—
> 630 – 8003.102.50—
> 800 – 10003.60——

Angular tolerances (groups D, A and T)

Shorter side (mm)Accuracy grade 1mm per 100 mmAccuracy grade 2mm per 100 mmAccuracy grade 3mm per 100 mm
≤ 3030′0.8730′0.8720′0.58
> 30 – 10030′0.8720′0.5815′0.44
> 100 – 20030′0.8715′0.4410′0.29
> 20020′0.5815′0.4410′0.29

The angle may deviate in both directions. Titanium castings use grade 1. Other values are agreed and indicated on the drawing.

Tolerances for radii of curvature (± mm)

Radius (mm)Accuracy grade 1Accuracy grade 2Accuracy grade 3
≤ 50.300.200.15
> 5 – 100.450.350.25
> 10 – 1200.700.500.40

For radii over 120 mm the linear tolerances apply.

Wall thickness tolerances (± mm), unmachined surfaces

Smallest lateral length of the surface (mm)DAT
≤ 500.250.250.30
> 50 – 1000.300.300.40
> 100 – 1800.400.400.50
> 180 – 3150.500.500.60
> 3150.600.600.70

Surface roughness of cast surfaces

Surface classD · CLA (µin)D · Ra (µm)A · CLA (µin)A · Ra (µm)T · CLA (µin)T · Ra (µm)
N7631.6————
N81253.21253.2——
N92506.32506.32506.3

N9, shot-blasted, is the standard delivery condition unless agreed otherwise. N7 and N8 need special treatment and must be agreed and shown on the drawing.

Cast holes, blind holes and channels

Diameter d (mm)Max. length, through holeMax. depth, blind hole
2 – 4≈ 1 × d≈ 0.6 × d
> 4 – 6≈ 2 × d≈ 1.0 × d
> 6 – 10≈ 3 × d≈ 1.6 × d
> 10≈ 4 × d≈ 2.0 × d

Cast slots and grooves

Width w (mm)Max. depth, open slotMax. depth, closed slot
2 – 4≈ 1 × w≈ 1.0 × w
> 4 – 6≈ 2 × w≈ 1.0 × w
> 6 – 10≈ 3 × w≈ 1.6 × w
> 10≈ 4 × w≈ 2.0 × w