I know this topic has been addressed before - but does anyone have a specific brand of forstner bit or brad point bit that works really well for boring cork rings? I have a drill press, and a boring jig in the style that Tom K. put out there (it's great), and then I got dumb for a few minutes and bought the el cheapo forstner bits and then got even dumber and bought el cheapo brad point bits. My 1/4" forstner bit makes a hole that leaves the ring loose on a 1/4" mandrel. Oh, I should note I'm working with no-bore rings, so the hole I'm boring is the first one in the ring, which I think complicates things. If no specific brands, does anyone have any little tips or tricks that might help me out? Thanks in advance for any help!

The German made bits seem to usually be of good quality. But as you're probably aware, a single bit cost as much or more than an entire set of oriental made Forstners.

Honestly though, I think you can stick with regular twist drill bits, pilot or brad point, for boring cork rings up to about 1/2 to 5/8 inch ID. Cork doesn't put much wear and tear on them and any decent set from B&D or DeWalt should be good enough. Forstners really aren't needed unless you want to bore a hole with a flat bottom. With your cork boring, you're going all the way through so I'll stick with twist drill bits.

Spade bits can be used when you get to the really large ID's, but we can cover that when or if you need it.

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Freud's "Precision Shear" Forstners are about as good as they get. They're the ones with the wavy (not saw toothed) rims. They have three different "lines" of Forstners and that one's their best. The part # all start with "PB" in that series (a 3/8" is a PB-002). These ones come out of Austria and there is no measurable run-out. Run-out is what made your 1/4" bit drill 9/32" or 5/16" holes most likely. You can get Freud's Precision Shear bits online, at Cabinet Hardware Suppliers and I THINK maybe even at Lowes. Freudtools.com has a dealer locator on it.

As for Brad Points, some of the truest running are from Fisch. You want their Austrian bits though not their Chinese bits. Be careful because they DO sell price point bits too. Their Austrian bits are clearly marked as such.

If you want some REALLY good bits, companies like Freud, Amana, Forrest City, etc... sell several different tip configurations (Brad, Split, Thru, etc..) of Horizontal Boring bits that are made for CNC boring machines. There's a wide variety of diameters including metrics. These all have 10mm shanks and are offered in 57mm or 70mm length. The sizes you'd be after range from $10-$20 PER bit. These are all carbide tipped and available in both Left and Right hand rotation. You need right hand for a drill/drill press.

Tom's right about the style of bits, and not NEEDING a Forstner, though a good Forstner will run more true than your Hardware Store variety twist drill. The "Thru-Point" mentioned above is a twist flute drill with a very steep angle on the cutting edges. It's made for boring clean holes through Melamine which is very chip prone. This is an ideal point for "enlarging" holes. Drilling cork, you won't live long enough to ever have to sharpen one (assuming you're a young man).


Mark Griffin
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C&M Custom Tackle
San Dimas, California

I use CMT forstner bits for woodworking. For boring holes in cork I use brad point bits from Lee Valley.

I have a few of the Fisch bits (and some called Vortex that may be the same) from the local Woodcraft and these things are so sharp you can not pick them up and put them in the drill without feeling like you are cut. But they do have a tendency to load up with shavings when drilling soft wood fast, so you have to clear them fairly often.