Tech Tip 14 Drilling out Exhaust Studs
Drilling Out Exhaust Studs
I had recently been talked into purchasing some very expensive drill bits, with the promise that they would be better than anything I had ever tried before. Ya, Right! They are guaranteed for life never to break. In fact if you do manage to break one, you receive two under the lifetime guarantee. They are also so hard they can’t even be sharpened by conventional means.
As a bonus, the points are anti-walk, you don’t have to chase the bit across your work surface anymore. The point digs in immediately and starts to drill. The story goes they are manufactured for the aircraft industry, by one of the major players, in-house for their own use. Code named Black & Gold by Santa Fe Freight & Salvage, these are supposed to drill just about anything!
This job ahead would be a good test because given the condition of the exhaust studs, there would be little chance of drilling a single hole and using an “easy-out” to back the studs out. I anticipated drilling a series of several holes, each increasingly larger than the previous to slowly remove all the stud and hopefully leave just aluminum to await a Heli-coil and a new stud. All, times four!
The first step is to prepare the surface for drilling. The surface must be smooth so the drill will go in straight. A Dremel with a fiber cutoff wheel is used to remove the rusted stud and leave a smooth surface, flush with the aluminum boss.