The DBF Series from Koch Maschinenbau is a precision 3-jaw chuck engineered for electrical discharge machining (EDM) and high-accuracy turning applications. Unlike general-purpose lathe chucks, the DBF is built to tighter concentricity tolerances and incorporates design features specific to the EDM environment — including sealed construction to prevent dielectric fluid ingress and precision-ground jaw guidance surfaces for low-runout clamping repeatability.

What makes a chuck suitable for EDM?

EDM turning presents unique workholding challenges. The chuck operates submerged in dielectric oil or deionized water, which accelerates corrosion on unprotected steel surfaces and can carry conductive swarf into jaw mechanisms — causing intermittent electrical shorts and inconsistent spark gap performance. EDM-rated chucks like the DBF address this through stainless steel or coated body materials, labyrinth or O-ring seals at all jaw entries, and tighter internal clearances that limit particulate ingress. Additionally, the jaw guidance surfaces are ground to sub-10-micron parallelism to minimize runout stack-up — critical when spark gap clearances are measured in single-digit microns.

About Koch Maschinenbau

Koch Maschinenbau GmbH & Co. KG, based in Germany, specializes in precision clamping chucks for EDM, hard turning, grinding, and high-accuracy machining. The company offers both standard catalog chucks and custom-engineered workholding solutions. Per-size specifications for the DBF Series — including outer diameter, clamping range, through-hole, and concentricity rating — are available through Koch or authorized distributors on request.