Two factors that will greatly impact your hole tolerance are the material, and the type of dowel pin fit. Depending on what type of mate you are trying to achieve, you will want to take both of these factors into consideration before starting your project.
Material and Plating Considerations
In general you will always want dissimilar material between your pin and your base material. The most common type of base material used in manufacturing is aluminum with stainless steel pins. Dissimilar materials will prevent galling and it will make it easier to insert your hardware. If your base material is bare then it should be a fairly straightforward calculation for your tolerance overlap. However, if you are going to have a part plated then you should consult with your plating company for how much build-up you want. Plugging tight tolerance holes prior to plating should also be considered to help ensure tight tolerances are met both before and after plating.
Dowel Pin Tolerance Overlap
The two most common types of dowel pin callouts are press fit and slip fit. A press fit ensures that the pin will remain embedded in the base material unless removed. A slip fit allows objects to be easily removed from the designated hole but ensures a firm fit. We generally recommend the below tolerances when inserting a pin:
Tolerance for press fit in Aluminum: -.0005’’ / -.0007’’
Tolerance for press fit in Stainless: -.0003’’ / -.0005
Tolerance for slip fit in Aluminum: +.0005’’ / + .0012’’
Tolerance for slip fit in Stainless: +.0005’’ / + .0012’’
Please consider all of the above criteria before starting your project and determining dowel pin hole tolerances. If you have any questions or comments please feel free to leave them below. For more information on dowel pins please refer to our ultimate dowel pin guide!