Low-wander Drill Bits

[Brandon Thill]

Recommendations?

[glenn bradley]

Almost any Bradpoint bit. I prefer Leavalley lipped bits but, these are not always appropriate. Other high-quality bits include fuller and fisch. For drilling things other than wood, split point bits are supposed to minimize wander.

[John K Jordan]

More info. What conditions cause drill bit wandering for you.

I have good luck by starting the hole with a center bit, used by machinists but great for wood. This lets the drill bit start without wandering, solving much of the problem.

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After the center bit, drill with screw machine drill bits which are shorter and stiffer. Then switch to a longer bit if necessary.

[Bill Orbine]

Using a punch or an awl helps in many cases.

[Brandon Thill]

I use punches often when accuracy is paramount, but still I'd like something better than ordinary bits for faster work where accuracy isn't critical but not unimportant either.

[johnny means]

I like tiny pilot holes.

[Robert Hayward]

John K has the answer. A cheap set of the center drills in various sizes are good enough for woodworking. If you plan on doing metal work also get a better set.

[John K Jordan]

I use punches often when accuracy is paramount, but still I'd like something better than ordinary bits for faster work where accuracy isn't critical but not unimportant either.

(oops, I wrote this yesterday and got busy and forgot to send it)

I like punches when drilling metal but with wood I've found it more likely a punched divot will end up slightly off the crosshairs because of the grain.

I should say that most of my deep drilling is on the lathe, drilling into end grain with standard twist drill bits.

I think several things can contribute to bit wandering in wood. What I can think of at the moment are: bit worn or unevenly sharpened, wandering when starting (usually from wood grain on surface), bit flexing (perhaps deflected by or following grain deeper in the wood), feeding too fast for bit RPM, and play/flexibility in the chuck and mounting if drilling on the lathe.

The center drills usually take care of the second problem since they are so stout they cannot wander when starting.
The screw machine bits help a lot with the third problem.

To minimize the last one when drilling on the lathe I use taper shank bits if I have the right size. To fit the tailstock I use bits with a #2MT or a #2MT adapter.
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If drilling on the lathe taper shank bits make a shorter connection and can eliminate some play/tolerance problems. Notice how much closer the tailstock can be to the wood with a taper shank bit:

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JKJ

[Bill Dufour]

Slocome drill or center drill to start then spotting drill. Gun drill to finish. If it is big enough use a boring head in a mill.
Bill D.

[Brandon Thill]

I'll look into those center drills for utmost accuracy. For the intent of this thread I bought a 25 piece HSS Bradpoint set from MLCS. We'll see how they work. Thanks for the tips everyone!