Fareed Mohmed · Engineering

Manufacturing Process vs. Achievable Tolerance

Select · Compare · Verify

Look up what tolerance a process can hold, or work backward from a required tolerance to find which processes can achieve it — plus a visual comparison across casting, forming, machining, precision finishing and additive manufacturing.

Find Tolerance by Process

Manufacturing Process

Achievable Tolerance—

Typical IT Grade (ISO 286, approx.)—

Typical Surface Finish (Ra, µm)—

Find Processes by Required Tolerance

Required Tolerance

"Best-case" means the target sits near the tight end of that process's range — expect a cost and time premium to hit it reliably. "Within typical range" means the target is comfortably inside the process's normal capability.

Visual Comparison

Bars span each process's typical achievable range on a log scale — tightest (finest) tolerance toward the left, loosest (coarsest) toward the right. Hover a bar for the exact range.

0.001 mm

0.01 mm

0.1 mm

1 mm

Casting & Molding

Sand Casting

±0.8 mm ±1.5 mm

Investment Casting (Lost Wax)

±0.1 mm ±0.4 mm

Die Casting

±0.1 mm ±0.3 mm

Injection Molding (Plastic)

±0.05 mm ±0.2 mm

Forming & Cutting

Sheet Metal Stamping / Punching

±0.1 mm ±0.3 mm

Laser Cutting

±0.05 mm ±0.15 mm

Waterjet Cutting

±0.1 mm ±0.25 mm

Machining

Drilling (Standard)

±0.05 mm ±0.15 mm

Turning (Standard)

±0.02 mm ±0.05 mm

Milling (Standard)

±0.02 mm ±0.08 mm

Precision Turning / Milling (CNC, Fine)

±0.005 mm ±0.02 mm

Wire / Sinker EDM

±0.005 mm ±0.02 mm

Precision Finishing

Grinding (Surface / Cylindrical)

±0.002 mm ±0.01 mm

Honing

±0.001 mm ±0.005 mm

Lapping

±0.0005 mm ±0.002 mm

Additive Manufacturing

FDM 3D Printing

±0.1 mm ±0.5 mm

SLA / SLS 3D Printing

±0.05 mm ±0.2 mm

Metal 3D Printing (DMLS / SLM)

±0.05 mm ±0.2 mm

Quick-Scan Table

Process	Category	Tolerance Range	IT Grade (approx.)	Ra (µm)
Sand Casting	Casting & Molding	±0.8 mm to ±1.5 mm	IT14–IT16	12.5–25
Investment Casting (Lost Wax)	Casting & Molding	±0.1 mm to ±0.4 mm	IT12–IT14	1.6–3.2
Die Casting	Casting & Molding	±0.1 mm to ±0.3 mm	IT11–IT13	0.8–3.2
Injection Molding (Plastic)	Casting & Molding	±0.05 mm to ±0.2 mm	IT11–IT13	0.4–1.6
Sheet Metal Stamping / Punching	Forming & Cutting	±0.1 mm to ±0.3 mm	IT12–IT14	0.8–3.2
Laser Cutting	Forming & Cutting	±0.05 mm to ±0.15 mm	IT11–IT13	3.2–12.5
Waterjet Cutting	Forming & Cutting	±0.1 mm to ±0.25 mm	IT12–IT14	3.2–6.3
Drilling (Standard)	Machining	±0.05 mm to ±0.15 mm	IT11–IT13	3.2–6.3
Turning (Standard)	Machining	±0.02 mm to ±0.05 mm	IT8–IT10	1.6–3.2
Milling (Standard)	Machining	±0.02 mm to ±0.08 mm	IT8–IT10	1.6–6.3
Precision Turning / Milling (CNC, Fine)	Machining	±0.005 mm to ±0.02 mm	IT6–IT8	0.4–0.8
Wire / Sinker EDM	Machining	±0.005 mm to ±0.02 mm	IT6–IT8	0.4–3.2
Grinding (Surface / Cylindrical)	Precision Finishing	±0.002 mm to ±0.01 mm	IT5–IT7	0.1–0.8
Honing	Precision Finishing	±0.001 mm to ±0.005 mm	IT4–IT6	0.05–0.4
Lapping	Precision Finishing	±0.0005 mm to ±0.002 mm	IT3–IT5	0.012–0.1
FDM 3D Printing	Additive Manufacturing	±0.1 mm to ±0.5 mm	IT13–IT16	6.3–25
SLA / SLS 3D Printing	Additive Manufacturing	±0.05 mm to ±0.2 mm	IT11–IT13	1.6–6.3
Metal 3D Printing (DMLS / SLM)	Additive Manufacturing	±0.05 mm to ±0.2 mm	IT11–IT13	3.2–12.5

Explanatory Notes

These are typical ranges, not guarantees

Every figure here is a commonly-cited typical range, not a spec any shop is bound to. Actual achievable tolerance on a real part depends on part size, material, wall-thickness uniformity, fixturing, tool condition and the specific machine — always confirm against your own shop's demonstrated capability for a critical dimension.

Tolerance and cost trade off exponentially, not linearly

Tightening a tolerance from ±0.1 mm to ±0.05 mm might add modest cost. Tightening it further to ±0.005 mm can multiply cost several times over — slower feeds, more setups, secondary finishing operations, and tighter inspection all stack up. Specify the loosest tolerance the design can tolerate, not the tightest a process can produce.

What an IT grade means here

ISO 286 IT grades describe a tolerance band that scales with feature size — the IT grade shown is an approximate typical grade for a mid-size feature made by that process, meant for quick comparison rather than as a substitute for looking up the exact IT tolerance table for your feature's actual size.

Roughing, then finishing, gets you the tightest numbers

The tightest entries in this list — grinding, honing, lapping — are almost always finishing operations that run after a part has already been roughed out by casting, forming or machining. The process comparison here is about the final feature tolerance, not necessarily a single operation from raw stock to finished part.

Related tools

For the clearance and tap-drill sizes that pair with a chosen fit, see Bolt Clearance & Tap Drill Sizes. For the base material properties feeding into a process choice, see Mechanical Properties of Engineering Materials.