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Old 03-31-09, 05:42 PM   #7
AC_Hacker
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Default Drill Rig #1

The drilling rig...

I started some notes on the thread over at EcoModding you might want to look there too. At some point, I'll put everything on one thread, probably here. See the EcoModder thread:

The Homemade Heat Pump Manifesto... - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

But here's the story...

A local farmer told me that he was able to drill a 35 foot well by using 2 friends an 2 cases of beer (smart farmer).

I started by making a T-handle test drill, that used a water hose, connected by a swivel coupling.


auger-T-handle-test(small).jpg - This is my first test drill, only with a shorter piece of drill pipe, so you can see what's going on. I actually used a 6 ft. section of pipe and when the auger advanced about 5 ft., I added an additional section of pipe. I was able to advance about 13 feet in about 35 minutes. One problem I encountered was that the hose kept kinking, so I had to hold it up with one hand and I turned the auger with the other hand. So I was able to advance 13 feet with only one hand. The other, and more serious problem was that because of the high sand content of the soil, I was having cave-in problems. I didn't know what was causing it, I just knew that my auger was getting stuck and was very hard to pull out of the ground. Later I would discover that drilling mud would solve the cave-in problem.


auger-T-handle-test_upper-detail(small).jpg - This is a detail of the swivel end of the auger. The swivel adapter is not eactly the same as 3/4 pipe thread, but by loading lots of teflon tape onto the threads, I got a satisfactory seal.


auger-T-handle-test_lower-detail(small).jpg - this is a detail of the business end of the auger. The water gushes through the pipe and flushes out the drill-cuttings. I have come to understand that the water is definitely part of the tool. It contributes more to the advancement of the drill than any effort on my part.

I live at the top of an 80-foot bluff and look down at a local river. I did notice that I was hitting rocks at about 12 to 13 feet. What I didn't realize at the time, but have come to know that every well driller understands very well, is that 14,000 years ago, an ancient flood deposited about a foot of clay mixed with basalt river gravel which over fourteen millenia has consolidated in what the locals know as 'hardpan'... it's tough stuff.

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AC_Hacker's Update, Sept 6, 2009:
At the time this was written, I thought I had, indeed hit hardpan. Later work, using tools that didn't obscure the nature of the soil I was digging through, revealed that I had actually hit an area of fist-sized rocks left from a 10,000 year old geological event. I developed a tool (the "steel claw"), shown later, that enabled me to remove the rocks and advance town to a depth of 17 feet where there was very wet, coarse black sand, very good for Ground Source Heat Pump work and worth the extra digging. At that depth, I was actually able to look down boreholes and the see the hardpan layer.
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You may not have anything like this where you live. In fact, a couple of blocks from here, thing might be much better, or much worse.


auger-base(small).jpg - This is the base of the gearmotor auger I put together. Based on my hand-drilling experience, I figured a small motor would do the job, so I got a 1/4 HP 25:1 permanent magnet gearmotor off ebay for $70. A 1/4 HP motor doesn't require a huge amount of structure to support and control, so fabrication was pretty easy.


auger-head(small).jpg - This is the gear motor head. I fabbed an 'L' bracket for the motor and used a 2" square tube for the vertical, and a close-fitting 2" inside receiver tube welded to the L bracket. it slides up & down well and doesn't have too much slop. You can see the hand cranked wench to raise and lower the gearmotor head. It's not optimum, but it works OK.

(By the way, I'm a terrible welder. I have a stick rig, which I have tried repeatedly to master, but it has won every time. So, I bought a crappy little wire-feed welder for $100 and it has worked wonders. Highly recommended.)

The gearmotor I chose is permanent magnet, so I can reverse the direction to unscrew pipe... very handy. I also have a bench test variac that I use to control speed. Works great.

Next post will detail the auger-head swivel... it's surprisingly important.

Best regards,

AC_Hacker
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Last edited by AC_Hacker; 09-06-09 at 11:59 AM.. Reason: AC_Hacker's Update, Sept 6, 2009
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