So upon getting a great deal on a Ridgid Octane 1,300 in-lb hammer drill with 9Ah battery recently, I needed to find a drill adapter for my Strikemaster 7" Lazer auger.
After a couple evenings of research, I didn't care for too many of the drill auger adapter options available for purchase. The HT Enterprises one looked decent, until I read reviews about it being made for 3/8" drills and the top part commonly twisting right off of it.
OK, well I'll have to make my own then.
Shouldn't be too hard I thought, drill some holes and maybe do some grinding and welding if necessary.
I'm a tall guy at 6'2", and I didn't really want to have to be bending over to drill my holes, so my drill adapter needed to be an integral extension as well. Similar to the Lazer hand drill handle, I figured it would be nice to be able to extend it for thicker ice, so I wanted to integrate that idea into it too.
I had some pieces of 1/2" electrical EMT conduit in the garage, and I knew that it was near a perfect fit into the auger, but it's pretty thin walled, and I wanted something with a little more beef to it. I measured the top opening of the auger at just a few thousandths under 3/4", 0.746" wide. Unfortunately, that meant that most medium-walled 3/4" tubing wouldn't work, as they typically measure right at 3/4", or a few thou over. Doing due diligence I checked, and found nothing locally that would fit.
So after a bit of searching, I found a piece of 3/8" black iron gas pipe at the local Ace hardware. This piece measures 0.664" outside diameter (spec is 0.675"), so a little on the smaller side, but it's the best thing I cold find that was close. It's only a bit over 0.08" different in diameter from the inside diameter of the auger, so only about 5/64", close enough that it should be OK.
I had already decided that I was going to use a 1/2" bolt for the part that would engage the drill chuck, and grind down three flat sides using my belt sander with a ceramic belt used for cutting metal and knife making. After cheking,
I found that the drill accepted about 1" of the bolt into the chuck, so I bought a 2" long bolt. I threaded 2 nuts onto the bolt, and lined up the 6 flat sides. This gave me a good reference to use while grinding the flats onto the first 1" of the bolt.
Once I had the flats made, I unscrewed the two nuts to the end of the bolt, and then clamped the nuts into my bench vice, and used a right-angle grinder with cutoff disk to cut the head off the bolt. I then completely removed the nuts from the bolt. The bolt was just slightly too big to fit into the end of the 3/8" gas pipe, so I chucked it into my new drill, and turned off about 1/16" of the threads on the belt sander, so it was a snug fit into the pipe. This assures that the two pieces are axially aligned, preventing wobble.
The piece of pipe I found at the hardware store was almost 42" long. It was a cutoff piece, and they only charged me for 2', which came up to a little over $5. Initially, this seemed like too long a piece, but upon sliding it into the auger, it actually looked about right so that the auger would start at arm level for me while drilling, so I left it 42" long. This gives me a ~15" extension at the shortest setting.
Time to drill holes in the pipe. I measured the Strikemaster butterfly shoulder screw at 0.235" in diameter. I didn't want a real tight fit, so I used a 17/64" drill bit (0.265") to make the holes. A slightly loose fit here makes it a lot easier to get the screw threaded through, and if you didn't have a drill press, it would give you a little leeway in case your holes weren't drilled perfectly centered and perpendicular through the pipe. I spaced them fairly evenly, about 6" apart, with 5 holes total. This gave me an adjustable length range of 2', or 24". The shortest length would allow a person to drill down a maximum of about 39", if you bent down to your ankles, lol. The longest length would allow a person to drill down a maximum of about 52", again if you bent down to your ankles. That's over 5 FEET!!!
Don't think I'll ever need to go
that deep!
I wanted to have a way to prevent the auger from falling down the hole in case it should somehow fall out of the drill chuck. While I don't think this will ever happen, I would just rather be safe than sorry. To do this, I needed a disk at least 8" in diameter. Turns out Walmart sells a frisbee in the dog toys section that is 9.5" diameter, for only $0.94. I found a couple trailer hitch cotter pins at Home Depot, for ~$2. They're 9/64" wire (0.140"), so I used a 5/32" drill bit (0.156") and drilled 2 holes close together in the adapter shaft, about 4" from the end of the pipe, to keep the frisbee in place.
Finally, I drilled a 3/16" hole through the pipe at 3/4" from the end. This would give me a good spot to weld the inside end of the bolt to the pipe, giving a mechanical joint between the pipe and the bolt in two places. All drilled holes were then de-burred.
The final step was to weld the modified bolt into the pipe. This was pretty straightforward. I welded the two spots on the pipe first, then I ran a bead around the top of the pipe at the base of the bolt. I used a stick welder, btw.
(See earlier pics of the weld job.)
Finally, I coated the pipe, inside and out, with a product called "Fluid Film". It's a Lanolin-based rust preventative that also helps prevent water from sticking to a surface, which then helps prevent frozen water sticking to things. It's a popular treatment for snow removal equipment, and I also regularly coat the head of my auger with it. I've found this really helps prevent ice on the cutting blades.
That's it! It seems to work really well! I've drilled about 75 holes with it now, and I haven't had any issues with it. If I were to mark it down for anything, it would maybe be weight. It's not real heavy, but it's 2 pounds & 3 ounces (35 ounces). The auger head weighs 5 pounds 11 ounces (91 ounces) with the Cold Snap cover, and the drill weighs 7 pounds 1 ounce (113 ounces), so in total, my drill/auger/adapter weighs in at 14 pounds 15 ounces. Let's just call it 15 pounds. Not bad, not bad at all!
Here's a few pictures detailing the length of everything and where my holes were drilled, in case you want to do something similar:
And finally, here's a video of it in action!!! That's a 7" hole in 7" of ice, in just under 3 seconds!!!