by Kat Griffin Kat Griffin

Tellurium Copper (Telco) and Manufacturing

Tellurium copper (Telco) performs the same as pure copper as an electrode material. It has a huge advantage because of its high machinability rating: 90% (free cutting brass = 100%). Pure copper has a rating of 20%. Its high machinability rating and fast speeds make it ideal for highly detailed, difficult to flush electrodes.

Telco is a machinable copper alloy manufactured for use as an EDM electrode material. An increase in machining of 90% is achievable versus pure copper. Not only will the machining of a Telco electrode be faster, but also you will be able to machine to sharper detail. A Telco electrode’s EDM performance is identical to pure copper.


SpecificationsFree CuttingBrass Hard Drawn CopperTELCO
Relative Machinability Rating100%20%90%
Electric Conductivity26%100%90%
>Approx. Wear Ratios Steel1:12:12:1


Benefits of Telco Electrodes

  • Telco wire EDM’s to finer detail and at faster rates than other EDM electrode materials (graphite, copper-tungsten and carbide).
  • Conventional machining of TELCO electrodes will not produce the dust associated with the machining of graphite.
  • Telco has a high resistance to DC arcing caused by EDMing under poor flush conditions.
  • Telco will produce fine surface finishes.

Telco Facts

  • Tellurium is an element with atomic symbol Te, atomic number 52, and atomic weight 127.6.
  • Telco is 99% Copper and 1% Tellurium.
  • 1lb. of tellurium is usually produced from the refining of 550 tons of copper.

Standard Tolerances

  • Plate (+/- .005) Thickness and Width (Minimal) Length
  • Round (+/- .005) Outside Diameter (Minimal) Length


Telco is available in both plate and round stock. MWI, Inc. stocks all popular sizes to fit your Telco electrode material needs.