Eagle Precision

Dimensional Tolerance Standards

Eagle Precision Investment Casting Tolerances and Standards

Investment casting, sometimes known as lost-wax casting, is a casting method in which molds are formed by coating wax patterns with several layers of refractory slurry, allowing the molds to dry, and then evacuating the wax through application of heat. The process is known for its ability to create products with complex internal cavities, accurate dimensions and smooth surface finish. Eagle Precision Cast Parts, Inc. is able to meet or exceed the following investment casting tolerance standards:

Dimensional stability

+/- .005” per inch

Wall thickness

.030” – .060” for small castings

.080” – .1” for medium and large castings

Flatness and Straightness

.005” per inch of length

Heavy sections: add an additional .01”

Raised features (lettering, numbering, logos)

Suggested dimensions: .02” (raised figures in a protective depressed pad)

Through Holes

Hole Size

Maximum Length

.04” to .08”

2x hole diameter

.081” to .2”

3x hole diameter

.201” to .4”

4x hole diameter

Blind Holes

Hole Size

Maximum Depth

Minimum Blending Corner Radii

.04” to .12”

.5x hole diameter

.5x hole diameter

.121” to .4”

1x hole diameter

.06” to .09”

> .4”

2x hole diameter

.09” to .18”

Characteristics of Investment Castings

  • Surface finish: 125 RMS
  • Typical weight range: 1 oz – 85 lbs
  • Largest overall dimensions: 24” x 24”

Design Recommendations

  • Large fillet and corner radii reduce stress in the part & improve appearance
  • It is recommended to design with the largest fillet radii that are practical for your project
  • Allow .030” min. radius for outside corners, where possible