Some holes are simply out of reach for a standard jobber bit. Whether you are drilling deep into timber, passing wire through a wall or reaching behind an obstruction, the best extra long drill bits give you the length to get there while staying straight enough to land the tip exactly where you aim it.
What to Look For
Length is only useful if the bit stays true, so flute design and body stiffness matter as much as reach. A well-made extra-length bit resists wandering and flex once it is deep in the material, where a poor one whips and drifts. Match the bit to the job. Aircraft-length bits suit deep general drilling, while a bellhanger bit adds a wire-pulling hole through the shank for running cable. Check the shank fits your chuck and that the point self-centres, because a bit that walks at the surface only gets worse the deeper it travels.
Our Top Pick
For most deep-reach work, an aircraft or extra-length twist bit in high-speed steel covers timber, plastic and mild steel with ease. If you run cable through walls and floors, a bellhanger bit earns its place by letting you feed wire straight through the drilled hole in one operation. American-made long bits hold their straightness well, which is exactly what you want when a small angle error at the start grows into a big miss over a long reach.
- Start straight: begin square and let the point self-centre.
- Reduce flex: keep the bit supported and feed steadily.
- Bellhanger: choose one with a wire hole for cable runs.
- Clear chips: back out often on deep holes to avoid packing.
Keeping a Long Bit True
A long bit magnifies every mistake. Starting at the wrong angle sends the tip drifting further off line the deeper it goes, so take a moment to line up square before the flutes bite into the surface. Ease into the cut, let the point establish the hole, then feed at a steady, measured rate. Whipping and vibration are signs the speed is too high for the length, so slow the drill down and the bit settles into a clean, controlled cut.
Clearing Deep Holes
Chips have a long way to travel out of a deep hole, and packed flutes will bind the bit and build heat fast. Withdraw the bit periodically to clear the debris, a peck-drilling rhythm that keeps the cut clean and the bit cool from start to finish. On metal, add cutting fluid to help carry chips and heat up and out of the hole so the edge keeps cutting freely. On timber, a slow withdrawal near the exit face leaves a cleaner hole and stops the bit from splintering the far side, which is well worth the extra moment on any job where the finished look really matters to you or the customer.