Shouldn't h6 Tolerance Dowel Pins be More Common?

[EngineerZach]

As per ISO 286-1 and ANSI B4.2, the dowel pin tolerance that offers the greatest number of recommended fits is h6 in a shaft-basis system.

If that's the case, then why isn't this tolerance more commercially available? I can only find h8 and m6 on McMaster, and Misumi isn't that much better. I'm not quite sure how I would achieve preferable fits with these tolerances of dowels; the major categories would be easy enough (clearance, transition, interference), but I wouldn't know where to start with the sub-categories (Loose Running Clearance, Sliding Clearance, Location Transition, Medium Drive Interference, etc.).

 

[SwinnyGG]

Expand beyond the convenience over cost MRO houses, and you'll figure out that buying h6 pins is really easy. Google search results in dozens of sources.