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Relief holes when using large forstner bit?

6917 Views 26 Replies 14 Participants Last post by  TZH
Hey all,

I'm trying to drill very large diameter holes (3-1/4") into hardwood blanks using a forstner bit. My bench top press says…"Heck no". I plan to take the workpieces to a buddies house to use a much larger floor model press. My question before I go..

Should I drill a series of 1/4" relief holes inside the perimeter of the large circle? Obviously avoiding the edges for a clean hole and the center for the Forstner bit point. Would this help or would it just encourage the bit to bite/grab on the relief holes?

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nah…don't bother. You'll just make the large drill bit angry. Let it do it's job. Definitely use a drill press if possible.

If you drill a small 1/8" pilot hole, you can flip it over and finish the hole to prevent blowout, if it matters.
Thanks Mark! I'll just use the larger press.

I'm trying to build a wine bottle tree. 3-1/4" hole is a bigger task than I anticipated.
If that fails you could make a template and do it with a router.
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Try using a fly cutter like this one. It only takes a narrow swath of wood and your small drill press should be able to handle it. I have one of these and use it all the time for larger holes.


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Be careful using a fly cutter, maybe read Candy's review on it.
The big drillpress should do the job BUT there are other ways: hole saw, router and straight bit with template, etc.
A hole saw could do the job.
Thanks all. I looked at a hole saw, the problem is that the material is 4" thick. I couldn't find a hole saw that was deep enough. The larger press worked, but even on the lowest speed setting it hung up on occasion. After about 32" of hardwood, I could tell the bit was dull. Now for the next task of trying to sharpen a forstner bit.

I'll post some pics when complete. Thanks again for the feedback.
I drilled 250 3.5" forstner bit holes to make these wine racks. Big drill press, slow speed, headphones and a long playlist. Then I drilled the same number of small holes!
Wood Beam Wood stain Hardwood Wine cellar


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whoa. nice work. a bit more than what I was doing.
There is NO Problem using a Relief Hole! I use them when I'm drilling an hole with a Hole saw. Should be NO Problem for a Forstner Bit. It certainly won't "Make It Angry" ...LOL..

The reason mine USE TO Smoke all the time was just that the Cut Sawdust had no where to go. Some Diagrams below of relief hole.

The Circle Cutter that Candy's Article is about is a Cheap Piece of Junk from Harbor Freight. About $6.00 Bucks I think. (Pic Below) They didn't mention that!

I have one from Lee Valley ($32.90) It works just Fine. MAX RPM Of 500/550! Faster than that and you're asking for Trouble! Also Pictured Below.

It also cuts an "Inside" or "outside' Cut.

Hope it's of some help.


Font Line Rectangle Parallel Circle

Font Line Parallel Rectangle Handwriting

Font Line Rectangle Circle Pattern

Product Font Parallel Auto part Electric blue

Line Parallel Font Engineering Circle



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What I've done is clamp the board to the table, and drill a hole about 1/3 the diameter, then 2/3's the diameter, then the full hole size. That way the bit isn't trying to cut out all the waste at once.
Hey Rick, That's a good idea with a hole saw.
The dust is fine and would drop through the smaller hole. I'll have to try that next time.

But that crazy wheel cutter bit looks like a medieval torture device. Too scary! Ha!

He's drilling a 4" deep hole so the hole saw wouldn't work. he's also using a forstener bit which cuts large shavings and wouldn't drop through a small hole - probably just get clogged.

I'd clamp a fence guide to the drill press and use an air hose and constantly clear the hole and work area. Do short 3/4 cuts and then blow it out, that's the key. Cut most of the hole, drill a pilot hole, flip and finish it.

The problem with trying to drill it out first is the blowout on the back - unless you plan on flipping it and finishing the holes. I see this as a huge waste of time. Just drill the damn thing already! Ha! and don't force it till it burns.

You might have to buy a new bit too.
I would do like renners suggested with a router, guide bushing, and template?

I use that method when I need to make holes bigger than my Forstner bits plus you get left over large diameter hole plugs.
The hole saw works if you flip the piece and attack the hole from the other side using the pilot bit as your registration. Not perfect, but it works. What's the design that it has to be a hole in a 4 inch thick piece?
dhazelton: "The hole saw works if you flip the piece and attack the hole from the other side using the pilot bit as your registration." YEP! Agree!

I measured my Larger Hole Saws last night. (3", 4" & 6" Dia.) 2-1/4" to 2-1/2" cutting depth is not a problem.

I can also change the bit that comes with the Hole Saw to a Longer one that will more than penetrate through to the other side, as You've suggested for a "registration" mark , or starter point to use the Hole saw from the other side.
dhazelton- I was building a version of this post by Paul from TN…

I guess you are right to flip the piece. I ended up doing that anyway with the forstner bit. Holes turned out great, but it took forever to drill them. I finished the project, but I haven't taken pics yet.
Here's another option to consider: YouTube

I've also used Diablo router straight bits - really long ones - to do this. The first one is just a straight bit - no bushing. After drilling a pilot hole through the piece, I take the router with the straight bit and go around inside the circle. The pilot hole is drilled with a forstner bit. I then flip the slab over, change the router bit out and put the other one in. This one has a bushing on the bottom to guide the router on the inside of the circle. This method leaves a pretty nice surface inside and requires a little less sanding than others I've tried. If desired, a hole saw can also be used to provide a more definitive "guide" around the outside edge of the circle on the first go-round. I've found these straight bits to be really helpful in this process. Sorry, don't have photos or video of my process…...yet. May have to talk to Scott (the guy who made the video I linked to above) to see if he'd be willing to shoot one.

You can't flip the piece over and follow the pilot hole for the hole saw? I do that all the time. Any tear out hides in the middle.
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