This building contains exhibits on the Holt side-hill harvester, dredge buckets used to build channels and levees, the new Foundries of San Joaquin County exhibit and the Floyd J. Locher Tool Collection.

This collection has over 3,750 different hand-and-foot powered tools representing 19 trades that have been practiced in San Joaquin County and California.  The tools date from late 16th century through mid-20th century.  The collection is the most complete west of the Mississippi River and is of national significance.