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which drill bits for oak beams?

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Forum topic by SnoSheriff posted 08-17-2018 06:12 PM 595 views 0 times favorited 12 replies Add to Favorites Watch
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SnoSheriff

4 posts in 89 days


08-17-2018 06:12 PM

Hi, I have 4”x6” hard oak beams that I will use to make a camping bench. These things are very tough to drill. I only have a hand cordless drill for this job.
- I used 1/2”x18” auger bit which had hard time drilling through 1 beam. The drill bit got very hot
- I used 3/16” drill bit to make a pilot hole for 1/2” lag bolts. But the lag bolt broke when screwing it in and the drill bit bent as well
- I used 6” nail (no pilot hole). The nail started bending after it went in about 1”
- I used 6” irwin speedbor and it seemed to work but my drill sure got a workout and it drained the battery

Ideally I’d like to use a threaded rod to connect everything together. So, I need to run a hole through all beams (4×4” wide). However if that’s not possible I could connect them by using lag bolts.

What is the best drill bit for this job? Is it possible to drill through 4×4” beams all at once? Do I need a bigger/stronger drill?


12 replies so far

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CaptainKlutz

526 posts in 1666 days


#1 posted 08-17-2018 07:42 PM

For long tough drill jobs, battery powered drills are not good. Stop by your local big box store and either buy a 1/2 inch chuck corded drill, or rent one of them. They are only choice for job like this.

The auger or flat speed bore bit should do job. Forstner bit might work better than auger, with slower heat build up. Can use some wax on drill bit as lubricant to clear chips, and drilling will be easier. For 4 inch deep hole, may need to apply it couple of times.

If wood is as hard as you say, and your auger bit was getting slow/hot, might have to sharpen bit between holes? For one time job, hard to suggest buying expensive drill bit, but even reluctant wood gives way to a carbide tipped forstner bit if others are failing. Just know you can buy several flat bits for price of single carbide forstner.

Best Luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

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John Smith

1427 posts in 334 days


#2 posted 08-17-2018 08:17 PM

my GrandDaddy used this “cordless” drill to drill sooooooo many holes
in white oak. . . . . worked for him – it’ll work for you too.

.

-- I started out with nothing in life ~ and still have most of it left.

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waho6o9

8477 posts in 2748 days


#3 posted 08-17-2018 08:22 PM

would wax help with the cutting?

Thanks Captain Klutz!

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CaptainKlutz

526 posts in 1666 days


#4 posted 08-17-2018 10:27 PM



- John Smith

Yes, an BRACE DRILL would also be very capable of drilling those holes. :)
Sorry I missed that one. You won’t find many BORG stores that carry a brace drill.
Need to shop antique stores or eBay for best value.
Garret Wade and Lee Valley sell modernized versions.


would wax help with the cutting?
- waho6o9

Only sharp bit really helps with actual cutting of wood.
Wax helps clear chips which carry heat out of hole and wax reduces friction in side walls; so it indirectly impacts cutting via lower temp and long edge life.

Cheers!

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

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SnoSheriff

4 posts in 89 days


#5 posted 08-17-2018 11:53 PM

I do like that manual drill :)

Ok, I just picked up 6” and 16” Bosch DareDevil 1/2-inch spade bits from orange box store. I’ll give them a try. What else can I use instead of wax?

I was planning on making more of these benches and coffee tables. I’m wondering if there is a better joinery method that I should consider?

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John Smith

1427 posts in 334 days


#6 posted 08-18-2018 01:18 AM

personally – I use a high speed and down pressure with spade bits.
I saw a guy use a cordless hammer drill with a 2” spade bit and
it was awesome !!! so if you have a hammer drill, try it out.

.

.

-- I started out with nothing in life ~ and still have most of it left.

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SnoSheriff

4 posts in 89 days


#7 posted 08-18-2018 11:05 PM

I discovered that FastenMaster 10” Timberlok screws will do the job. I used 18v hammer drill for assembly. I need bigger drill ;)

View BFamous's profile

BFamous

174 posts in 292 days


#8 posted 08-18-2018 11:17 PM

With beams that size you have a lot of joinery options… Moat of which will save you the expense of those Timberlock screws.

For a simple example, you could do a standard mortise and tenon on the 4×4s running into the legs, and the door a 1” oak dowel through the 4×4s running between the legs… That would all mean no mechanical fasteners.

-- Brian Famous :: Charlotte, NC :: http://www.FamousArtisan.com

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SnoSheriff

4 posts in 89 days


#9 posted 08-18-2018 11:30 PM



With beams that size you have a lot of joinery options… Moat of which will save you the expense of those Timberlock screws.

For a simple example, you could do a standard mortise and tenon on the 4×4s running into the legs, and the door a 1” oak dowel through the 4×4s running between the legs… That would all mean no mechanical fasteners.

- BFamous


Yes, I prefer all wood solution. I had a hard time finding drill bits that would cut through these very dense oak beams. I don’t have a drill press and I’d need to make sure the holes are aligned for the dowels. Also these beams aren’t perfectly the same sizes.

View runswithscissors's profile

runswithscissors

2866 posts in 2196 days


#10 posted 08-24-2018 11:34 PM

If you have a bandsaw, mortise and tenon joints for the legs are quite easy to do. I’d bore a hole (maybe 1” diameter.) at the end of the mortise, saw out the mortise along the grain with the bandsaw, and square up the corners with the bandsaw, a long blade in your jigsaw, or a chisel. Making the tenon is so straightforward that it needs no description. I made a bunch of these joints for support frames for 250 gallon water tanks (rainwater harvesting, you know). Of course a simple mortise like that will need to be pinned with dowels. Or you could use big galvanized spikes in pre-drilled holes.

If you use lags, the pilot holes should be equal to the root diameter of the lag screw—and the first inch or so of the hole equal to the nominal diameter of the unthreaded portion. And be careful in tightening lags. You have a lot of power with a wrench on a screw, and the screw threads can strip out the hole quite easily, though not so much so with oak, I guess.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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runswithscissors

2866 posts in 2196 days


#11 posted 08-26-2018 04:13 AM

One more thing: I think a forstner bit would not be a good choice, for 2 reasons. First, they are very poor at clearing chips, especially in smaller diameters. Second, the short cutting end means it is quite easy to bore a curved or crooked hole without realizing it, until you try to drive a bolt or threaded rod through.

Spade bits can be quite effective (though also easy to steer wrong). Their cutting efficiency improves a lot by filing spurs on them. I use an appropriate size round file to cut the spurs, such as a chain saw file. Clamp the bit in a vise, then tilt the file as you cut into the cutting edge flats, leaving spurs on each side. Tilting the file provides relief for the bit. When these get dull, it takes just a minute or 2 to touch them up. I realize that you can buy spade bits with spurs now, but resharpening them is problematic because of the shape they grind into them. It’s so easy to do your own. They cut a truer, rounder hole this way too.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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WoodenDreams

206 posts in 82 days


#12 posted 08-26-2018 07:57 AM

A hand drill will work, The old fashion way, but it’s more work…. A battery operated drill just isn’t enough drill power and hard on battery life…. A good 1/2” or 5/8” electric drill has more sustaining power. I have had to replace a 1/2” electric drill once, the armature in motor burned up using a auger bit in drilling through 6” hardwoods. use a 6” or 8” reg drill bit, auger bit or better used in douglas fir or pine.

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