Electro Arc disintegrating heads are designed to be used at any angle, which helps you disintegrate broken tooling in hard-to-reach areas. If you are disintegrating in large or deep holes you may need to use a shank or extension with your electrode. When you are using a metal disintegrator it is recommended that you keep the electrode as short as possible. 1/2 -2 times the depth of your intended cutting depth. This is because metal disintegrators are designed to cut only with the tip of the electrode, it also reduces the chances that the electrode will bend during disintegration. Metal disintegrators work using a reciprocating vibration along the axis of the electrode to cut, this means that if the electrode is extended beyond recommended length size whipping can occur. This side whipping can cause side arcing which will slow your cutting time and has the potential to damage the hole.
If you need to disintegrate large holes (larger than .312) you will need a shank to fit the electrode into the collet. You can also purchase extensions to disintegrate into deep holes. In either case, extra care should be taken to reduce the whip on the tip of the electrode. Electrode whip and side arcing can be reduced or eliminated by using a non-conductive guide bushing or something as simple as a piece of wood to act as a brace. Extra care should be taken in sizing the cutting tip of the electrode. A certain amount of whip can be unavoidable and the effects of side arcing can be compensated for by reducing the size of the cutting tip.
Using extended electrodes to remove deep drills, longer than 4 inches up to 5 feet. In order to maintain speed while eliminating side arcing, use a bushing to keep the electrode centered. The material you use for the bushing should be heat resistant, abrasion resistant, and material that will not absorb water or oil. Some examples would be Bakelite, Nylon, Ryertex Grade LE or G10 Fibreglass or equivalent, wood can be used if there is no alternative readily available.
Bushing OD should be .003″ to .006″ under the hole size and .005″ to .008″ over the OD of the electrode used. We recommend you use bushing lengths of 1 to 2″. Mill flats on three sides to form a three-cornered bushing which will allow the coolant to flow back past the bushing (otherwise hydraulic pressure could force the bushing out of the hole). Fo example, when removing a 1″ diameter jobber length drill 5 feet deep, two bushings were used, held in place on the electrode by wrapping electrical tape above and below each bushing. Two .312″ x 36″ electrodes were made from 1″ OD bar stock and soldiered to the electrode.
If you are attempting to disintegrate broken tooling in a situation where you are unable to get a straight set-up with the electrode aligned along the center line of the hole, you can use an electrode offset holder.
Adjustable offset electrode holders allow you to disintegrate at an angle that the disintegrating head is unable to reach. This is an easier method than bending an electrode, considering the delicate nature of electrodes. An offset must be made of conductive material and must accommodate the collet adapter and collet nut to securely hold the electrode.