If the pin is rolled into a cylinder shape with a single open seam it is likely a spring steel rollpin.

http://www.engineersedge.com/roll_pin.htm

There are metric-dimensioned versions as well. To remove it you drive them out with a cylindrical tip drive pin punch of a diameter slightly smaller than that of the hole the pin is installed in.

http://www.amazon.com/Starrett-S565P.../dp/B0006J4OUC