Deep hole drilling in hardwood

[Ian B]

Recent project; building what the Dutch call a "dam". This is a canal crossing with a 2' diameter pipe through it, allowing the canal to still flow water and machinery to cross the canal.

The dam consists of 2 hardwood ends, a pipe and a soil backfill. In this case, each of the ends is made of azobe.

The ends consist of a 20' long horizontal 8" square beam with 2 uprights, and a series of 2" x 8" planks, all screwed & bolted together. A finished dam end weighs about 3/4 ton. All straightforward stuff, the hardest part was drilling the holes for the bolts at the beam joints. 1 1/4" diameter holes, 14" long. This was to take M24 studs.

Azobe is incredibly hard and dense - it sinks in seawater. Not the easiest of woods to work.

I made up a wood drillbit with an extension shrunk on, fine so far. Then I tried turning the drill. Oops. My electric drill wouldn't even look at it, and there was no way of getting almost 1/2 ton into my drill or mill. Another solution was needed. So I ended up using this:

http://smg.photobucket.com/albums/10...t=IMGP4371.jpg

http://smg.photobucket.com/albums/10...t=Imgp4376.jpg

I'd made the tractor drill to drill holes for planting trees, and it works really well at that. A bit of modifying let me use it to drill through the azobe. I had to pull the drill out a dozen times to clear the chips, but it got there in the end. Obviously, being a swinging arm type of drill, alignment was a problem, but it's easy enough to roll the tractor back & forth to keep everything sort of aligned, and greasing the drillbit helped.

The steel drill guide worked perfectly; all holes came out exactly where they were expected.

Here's one finished endpiece, ready to go in:

http://smg.photobucket.com/albums/10...t=IMGP4451.jpg

In place, just need to backfill:

http://smg.photobucket.com/albums/10...t=Imgp4556.jpg

Just need to make the second one, and that's another job out of the way.

Ian

[MTNGUN]

That's a heckuva drill ! ! ! I like your can-do attitude.

[Black_Moons]

Awsome rig!
Might I recommend a 500RPM airdrill for your next pain in the ass project?
I have one, at 90psi my 5HP 18CFM air compressor can just barly keep up. 5hp~ in the palm of your hand! And awsomely, when it 'catchs' it just stalls with roughly the same torque you normaly use, insted of trying to snap your wrists clean off. Works wonders when I had to run a 6" bimetal hole saw in metal.

[Ian B]

Thanks guys,

Yes, it was the "getting wrists snapped" that put me off exploring handheld drills any further. I have one of those Makita hammers that also has a drill + hammer setting; low geared, endless torque. If it catches on something, the drillbit stops rotating and you start. Scared me.

The two mods that I made after the pics had been taken were to weld a conical stabbing guide onto my drill guide - made getting the drill back in the 'ole much easier. I also bypassed the chuck and put a 6 spline adaptor straight on the end of the drill, which fits straight onto the tractor drill. After that, it was a breeze.

No problems for the (18hp) tractor - I regularly bore 16" holes into hard clay, 2 feet deep, the drill went through the hardwood with the engine barely above tickover.

Ian

[Black_Moons]

Yes the better 'high torque' electric drills all offer 'safty' clutchs.. Or at least, current monitoring where they shutoff the motor if it catchs.. Of course, how accurate those safty clutchs are is questionable.. hence why I like my air drill , same stall torque as full operating speed, and torque settable by air pressure. And they get cold with use, insted of hot.

[jkilroy]

Hope that pipe is big enough! A few years back I made a similar setup for a 48" culvert, except much more rugged, the entire thing was made from new rail road ties. Sunk about 8 ties 5 ft into the ground on each side, etc. etc. Had a real storm come though, one of those multiple inches per hour, for hours, deals and it blew the hole assembly clean away!

[Ian B]

jkilroy,

Not a problem in Holland - the place is so flat, that we rarely even see movement in the surface of the water (although it does move). The authorities stipulate a 1 foot diameter or greater pipe - I used the bigger one simply because it looks nicer!

Much more of a problem is the thing blocking up with mud, but at least with this one I can send the wife in with a shovel to clear it out...

Ian

[airsmith282]

now thats a cool mod , can it drill a water well ,, great work man very inventive

[Your Old Dog]

Nicely done project. Mind if I ask where you're buying your "ambition" at?? Talk about a daunting task

[wierdscience]

Nice job,what does super dense timber like that cost?I imagine the sawmilling process alone isn't cheap on that dense species.