Been on lots of old work jobs where a flex bit would have saved a lot of drywall trenching and repairing.
I haven't gotten around to getting one of these because I figured the 36" one would be the most useful, but no one stocks that length. 54" and 72" seem to be everywhere.

36" is a whole lot easier to move around with and you can always the the extention shaft.

I've asked around here and no one has ever used one. Strange. They seem incredibly helpful.

I have used the flex bits with great results. Mostly the 54" bit. Check out the Home Depot I have seen the 36" bit there. Never used one so I do not know how flexible they are.

Haligan: I, too, keep a flex bit in my truck. It has made drilling through wall plates easy and less-invasive. In fact, one time I bent a scrap piece of 3/4" EMT in to a 30-degree radial bend, made an access hole in a wall, and used the EMT to guide the flex bit straight through the wall plate to get into a basement. It was a situation where I could not drill up from the basement because the foundation was in the way and this wall extended beyond the foundation.

I have not used a 36" so like Capt Al said, you may have troubles getting it to go where you want it to go. I would think the longer ones would easier to bend while drilling, unless you're restricted by working space.

If they made one with a view finder that would be helpful! (to see where it's drilling)

I liked these when they first came out, now I won't bother.

I drilled into another building with one, by accident once. I'l never use one again!

I have also gotten one stuck in a wall and could not get it out.... I have also found where other people have gotten thiers stuck too. If it happens there is no way to get it out, you have to cut it off, no easy task!

I've had a similar experience with getting them stuck. Seems to me that the drill has to put a lot of torque on these bits to get them through. The problem is that the shafts are small to allow the bending action but yet its hard for a chuck to get a good grip on them. At the same time, the more you bend them the harder the drill has to work. They are certainly useful, however, I always get a knot in my stomach when I use them as they are not 100% ideal. Any suggestions from the rest of you out there on drill/bit combos that are full proof? Maybe its not the drill/bit combo but the technique ... any pointers?

By the way, I have not had great experiences with the extensions.... seems those 2 allen screws don't cut it. There is nothing worse than getting your bit burried in the wall becuase the extension came loose. Have others had similar experiences. If you have had good experiences with the extensions, any pointers? (Granted I know that drilling 8 feet into a wall makes it difficult to stick to 1.25 inches from the edge of stud ... with good aim, you'd be surprised at how straight these drill runs can be however!!)

A while back someone posted about a setup they had that used 1/2" iron pipe lengths as extensions. They said they were able to drill fron basement to attic in two story homes. I can't remember the name of it, maybe they will see this and post.

I use them all the time a real saver from tearing up people's homes, how ever in the new jersey area watch out for the new pvc water lines and the new style gas lines as well. these bits tear right through them with little resistance!!

BigB, Are you referring to Greenlee 1440G pipe bit set? This is a set of ship augar bits that use 1/2" pipe to make your extension.

We use these all the time. They take a lot of practice to become really good with one without making a big mess. A 36" bit (IMHO) would be useless. The extensions are stiff, so the flexibility would be lost. We use the 72" models.

Tip for use:

1. Use a power drill, not a cordless
2. Use the placement tool.
3. When drill across floor joist, drill your first hole with at least a 1" spade bit. Make that hole about 1 1/4" from the bottom of the joist. The hole helps you to guide the bit with the placement tool through the other joist. Be carefull to get it started straight and low or you'll be repairing the floor above.
4. IMPORTANT!!!! As the bit goes through the wood, Stop the drill quickly and push the bit to the next joist/stud. This way you can feel the bit hit the PVC waste line before you drill it.
5. Always keep 2 of these bits on the truck. They will break where the drill meets the shank and you'll hate it if you can't finish because you break one.
6. Purchase the model with the auger and screw tip. When the leading edge of the auger get dull, the bit will not go through.