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Why Overlapping Holes Grab and Bind
When you drill a second hole that breaks into the first one, the bit loses material to cut on one side. That unsupported edge is where the trouble starts. Instead of cutting evenly around its circumference, the cutting lips catch on the thin wall between the holes, the bit deflects into the open void, and the flutes wedge against the sidewall. With a standard twist bit or spade bit, this happens almost instantly.
Binding is worst with aggressive screw-tip bits and large diameters. The screw tip pulls the bit forward whether there is wood to cut or not, so the bit lunges into the empty space and jams. In softwoods like pine or cedar, the wall can also tear out rather than cut cleanly, leaving an oblong slot and a stuck bit. In hardwoods like oak or maple, the bit is more likely to stall the drill and twist your wrist if your clutch isn’t set correctly.
The fix is a combination of the right bit geometry, reduced feed pressure, and a way to keep the bit from wandering into the void. You don’t need a drill press for every job, but you do need to control the cut.
Choosing the Right Bit for Overlapping Holes
Not all wood boring bits handle interrupted cuts. For any hole that overlaps another, avoid self-feeding bits.
Forstner bits are the most reliable choice for overlapping holes by hand or in a drill press. The rim cuts the perimeter first and the center spur keeps location, even when 30-40% of the rim is cutting air. They need more downward pressure than a brad-point, but they don’t grab. A sharp set of Forstner bits will give you the cleanest sidewalls and flattest bottoms if you are making a slot, a row of holes for a mortise, or an oversized hole made from two or three overlapping bores.
Brad-point bits are a decent second option for holes up to about 1/2 inch. The outer spurs score the wood and reduce tear-out, but once more than about 25% of the diameter is overlapping, the single center point loses reference and the bit will wander. Keep these for small, shallow overlaps only.
Spade bits and auger bits with a threaded lead screw are the worst for this job. Both are designed to pull aggressively. When the lead screw finds no wood on one side, the bit cocks sideways and binds. An auger can stall even a powerful drill and, because of its deep flutes, is harder to back out once stuck. If a spade or auger is all you have, you can grind or file the screw tip down to a low pyramid point to reduce the self-feed, but it is still a compromise.
Hole saws have the same void problem on a larger scale and will chatter violently if you try to overlap them. Don’t overlap hole saws freehand.
| Bit Type | Risk of Binding on Overlap | Best For | Trade-off |
|---|---|---|---|
| Forstner | Low | Overlapping holes 3/8″ to 2″ in any wood | Requires firm feed pressure; slower; needs 1,000 RPM or less for bits over 1″ |
| Brad-Point | Medium | Small overlaps up to 1/2″ diameter, shallow depth | Wanders if >25% of diameter is unsupported; limited size range |
| Spade Bit | High | Single, non-overlapping holes where speed matters | Cheap and fast, but tears the dividing wall and grabs easily |
| Auger / Screw-Tip | Very High | Deep single holes in solid stock | Excellent chip ejection, but screw tip lunges into the void and locks the bit |
Technique That Prevents Binding
Even with a Forstner bit, technique matters. The goal is to keep the bit cutting on its rim, not skating into the open hole.
Start by drilling the holes at the ends of your pattern first. If you are making a slot from three overlapping 3/4 inch holes, drill hole 1 and hole 3 first, leaving a solid web of wood between them. Then drill the middle hole. This gives the bit wood to reference on both sides for as long as possible, instead of having it break into a void on one side for the entire cut.
Clamp the workpiece solidly and back it with scrap. Any movement while the bit is half-engaged will amplify binding. If you are drilling near an edge, clamp a sacrificial block alongside to prevent blowout.
Use a guide. The cheapest effective guide is a scrap of 3/4 inch hardwood or MDF with a clean hole drilled in it at the size you need. Clamp that template over your workpiece so the Forstner rim is fully supported as it starts. For mobile work, a portable drill guide jig with a bushing does the same thing and keeps the bit perpendicular. Without a guide, your hand will follow the path of least resistance — straight into the existing hole.
Score the perimeter first. With the drill at moderate speed, lightly touch the spinning Forstner to the wood to cut a 1/16 inch deep ring before committing to full pressure. That scored ring resists wandering when the bit later breaks through to the adjacent hole.
Feed slowly and clear chips. Overlapping holes trap chips in the interconnecting slot. Peck the bit — drill 1/4 inch, retract to clear chips, drill again. Forcing the bit packs chips, increases friction, and heats the rim. In hardwood, heat will glaze the cutting edge and make the next pass bind even more. Let the bit cut; don’t lean your body weight on it.
Drill Settings, Speed, and Clutch
Speed is a common mistake. A fast-spinning bit with an interrupted cut vibrates and catches. Forstner bits should run slow: 1,500-2,000 RPM for bits under 1/2 inch, 700-1,000 RPM for 3/4 inch to 1-1/4 inch, and 500-700 RPM for anything larger. Most modern cordless drills can do this on their low gear. If you only have a single-speed drill that runs at 2,800 RPM, you will struggle to control a large Forstner in an overlapping cut.
Set the adjustable clutch to a mid-range setting (around 10-14 on a 20-step clutch) when starting out. If the bit does grab, the clutch will slip instead of wrenching the drill. Once you feel the cut is stable, you can increase the clutch or switch to drill mode. On a hammer drill, make sure hammer mode is off. Hammer action does nothing in wood except make the bit bounce.
Use a drill with enough torque but not excessive length. A compact 18V-20V drill/driver is actually easier to keep vertical than a heavy 60V hammer drill for this finesse work. Hold the auxiliary handle if your drill has one, keep your wrist straight behind the drill axis, and keep your body to the side rather than directly behind the bit.
If the bit does bind, don’t keep pulling the trigger. Release, reverse the drill at low speed while pulling straight back, and wiggle minimally. Rocking the drill sideways while stuck reams the hole oversize and bends the bit shank.
When to Use a Drill Press or a Router Instead
A drill press solves most of the problem mechanically because the quill cannot deflect sideways. If you need more than four or five overlapping holes, or you need them in hardwood thicker than 1-1/2 inches, clamping the work to a drill press table and running a Forstner at low speed is faster and cleaner than fighting it freehand.
For a long slot where two or three overlapping holes are just the roughing step — for example, a cable pass-through or a mortise for a latch — consider drilling Undersize and finishing with a router or chisel. Drill overlapping 5/8 inch holes where you need a 3/4 inch slot, then clean the walls with a sharp chisel or a flush-trim router bit against a straight edge. You get a straighter slot with far less risk of a bound bit.
You don’t need to buy the most expensive bits here. A mid-price Forstner set from a reputable toolmaker will outperform a cheap spade set for overlapping work every time, and it will last years if you don’t overheat it. Save your money for a good guide or a solid clamp setup — those prevent binding more than any premium coating on a bad bit geometry will.