This paper presents the OCR pipeline created for ParliamentSampo - Parliament of Finland on the Semantic Web, a Linked Open Data (LOD) service, data infrastructure, and semantic portal for studying Finnish political culture, language, and networks of the Members of Parliament (MP). A knowledge graph of linked data has been created based on ca. 967 000 speeches in all plenary sessions of the Parliament of Finland in 1907—2022; the data is also available in XML format, utilizing the new international Parla- CLARIN format. A central part of the historical debates 1907-1999 was available only as PDF documents of fairly low OCR quality and had to be OCRed first; this paper reports lessons learned from this process.