STARTERS Brass Multichannel Tubes for Small Hole EDM are made exclusively for SST Consumables by the world’s foremost tubing manufacturers and are made from Cu65Zn35 virgin materials. 

Multichannel fast hole tubes are also referred to as Coreless tubes and are often used to overcome certain disadvantages of plain single channel tubes. Since the center of a plain tube is hollow it can leave a spike or needle in the center of the EDM'd hole. This can lead to several disadvantages:

• Inability to EDM a blind hole
• In deep holes, the spike can wander and short out against the tube I.D.
• At breakthrough, the loose spike will often lead against the tube I.D. causing excessively long breakthrough times

As multichannel tubes have a geometric cross section, the multichannel tube sweeps the entire area of the hole and eliminates any spikes and spike related issues.

Coreless fast hole drilling tubes are the preferred solution when drilling deep or counterbored holes. They will burn slower than a plain tube though since they have more material to remove from the hole.

Multichannel tubes are manufactured by inserting either an insert or two or more small tubes into the I.D. of a larger tube and then drawing the composite to finished size. As a result of uneven drawing and springback forces due to the non-uniform cross-section of a multichannel tube, the O.D. roundness is not as good as a standard tube and must be measured only at the largest point.