Our Story


It all started in the early 1930's on Chicago's South side. Robert Dempster Sr. bought his first lathe and began manufacturing swivel joints for a lamp company in his basement. Fast forward to 1950 and Demco Products Inc. was founded. Demco Products Inc. is a production and precision CNC machine shop. Currently located in Oak Lawn IL with a 15,000 sq. ft. facility and over 30 CNC machines.

Beginning in 1978, Demco Products manufactured a line of Filter Housings that were sold to various companies. In the late 1990's, Robert Dempster Sr. and his 2 sons, Robert Dempster Jr, and William Dempster decided to start 3B Filters.

3B Filters was Incorporated in 2001. Our line of High-Pressure Filters is sold all over the world to the aerospace, petroleum, and chemical processing, transportation, and defense industries to name a few. In 2016 3B Filters proudly earned our ISO 9001:2008 certifications. In order to continue with our quality program we earned our ISO 9001:2015 Certification in 2018. At 3B Filters Inc. we pride ourselves on 3 core values, Quality, Dependability, and Service.


Quality Products

  • Made in USA
  • Inspected at manufacturer & 3B Filters
  • Certified Quality Management System

Low Prices

  • Source from multiple suppliers for competitive pricing
  • Pass on savings from suppliers
  • Manage overhead and inventory to keep margins competitive

Unparalleled Customer Service

  • Quote within 24 hours, often within hours
  • Equip our customer service team with the knowledge and tools to cross OEM parts
  • Convert customer specifications into 3B Filter part numbers

Short Lead Times

  • Hold an inventory of replacement elements for 3B Filter assemblies and OEM
  • Partner with Demco Products, Inc, our in-house manufacturer
  • Maintain multiple American suppliers to source the shortest delivery