Investment Casting Design & Buying Guide

Rules of Thumb for Investment Casting Design

To get the most from your investment, it's important to understand investment casting design & purchasing guidelines.  Investment casting design and production is a precise activity and understanding the process can help buyers avoid problems and bumps in the road to obtaining great investment casting results. 

When it comes to investment casting design, the tolerances listed on this page can be expected as a general "Rule of Thumb."  Additionally, closer tolerances may be obtained by use of additional controls or secondary operations within the investment casting design process.

Linear Tolerances:

Up to .250"     ± .004" per inch
.251" to .500"  ± .005" per inch
Over .501"      ± .005" per inch


Axial straightness + .005" per inch. Some castings may be mechanically straightened to closer tolerances.


Flatness refers to a single plane surface.  In investment castings, it is usually a result of the volumetric shrinkage within the part.

Thickness Flatness

up to 1/4"

004" T.I.R

1/4" to 1/2"

008" T.I.R.

1/2" to 1"

012" T.I.R.

1" to 2"

016" T.I.R.


Casting diameters will be concentric within .005" per inch of separation.  


1/32" minimum is recommended. Larger is more desirable.  

Gate areas:

A gate width of .010" to .020" is normal.  Flush removal requires additional labor and expenses.

Surface Finish:

80 to 120 RMS are average.  

Hole Positioning:

± .004" per inch from any single reference point.


the Net Shape Casting Advantage
Contact Precision Castings of Tennessee

Investment Casting
Stainless Steel Casting
Aluminum Casting
Ductile Casting
Steel Castings
Superalloy Castings
Cobalt & Nickel Based Casting
Bronze & Copper Castings
Tool Steel Casting
Military Specification
Woodworking Steel Casting
Net Shape Casting 101
Casting Advantages
Casting Process
Casting Terminology
Design Guide
News & Events
Contact Us
Services & Capabilites
Metallurgical Testing
Heat Treating
Plating and Painting
Tooling & Machining
Rapid Prototyping
Casting Surface Finishing
Quality Assurance
Process Control
Spectro Analysis
Inspection & Testing
Industry Solutions
Terms & Conditions Available Upon Request
script type="text/javascript"> var _gaq = _gaq || []; _gaq.push( ['_setAccount', 'UA-19378463-1'], ['_trackPageview'], ['b._setAccount', 'UA-2722905-44'], ['b._trackPageview'] ); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + ''; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })();