I haven't tried a bush pipe but have looked into pipe making in general, and made one from a hobby kit (block of briar with the drillings and some basic shaping done, and a ready-made stem - you carve the outer shape and finish it). I'd imagine the tough bit in the field is doing the drillings, especially when one considers that pipes are usually made of pretty hard woods. (I thought I was going to use a knife on the hobby kit and was soon disabused of that notion - ended up using a hacksaw and rasp for basic shaping, then a rotary tool with various cutters, burrs and sanding bits to do the finer work, and a sponge sanding block to finish off, and it still took ages.)
The pointy hole-making thing on the back side of a SAK would probably manage the mortice for the stem, but cutting the bowl could be tricky. Maybe it could be burnt out with something like a red hot poker, but I'm not sure how clean the inside would be (scrape the carbon off, maybe). What does Mors say about making the bowl? For making at home, one of those flat woodworking bits can be ground into a round-cornered shape. I've done this and tried it on a lump of softwood, and it worked (just never got round to sourcing a more suitable bit of wood). The main thing with this is that the blank is square-sided and can be held in a vice, and a power tool is really needed. Another possibility is a pipe reamer, like this...
http://www.gqtobaccos.com/castleford-pipe-reamer/#.VYUundgcGHs
If the majority of the bowl can be burnt out, that could be used to make a neat job of finishing the inside (or at least scrape off most of the carbon in a more consistent way).
There's a tip in pipe making circles, where you smear honey on the inside of the bowl to condition it before you light up. I did this on my hobby kit pipe, and also do it with any new pipe I get. It seems to help - with the hobby kit, there was a slight sense of smoking a campfire the first couple of bowls, but it seemed to settle pretty quickly as the honey got carbonised and turned into the beginnings of a cake. I used runny honey (or the liquid part from an old jar of stiff honey that has long since settled out), and get it fairly wet, but not running down the sides. Get it so that it all looks glossy when you shine a light into it. Apply with the pinky, only a tiny amount needed.
Here's the hobby kit briar block as supplied...
And the finished pipe (before applying honey and lighting up)...
The finish is boiled linseed oil with a little bit of pine tar mixed in to darken it. It looks smaller and maybe shorter in the photo than it is in reality - it's normal pipe size. The top of the bowl is 36mm diameter, 45mm high, and 140mm long overall. Smokes very well, although it can get a bit hot due to the wall thickness reducing thanks to the fluted shape (chose that to echo the shaping of the stem). The bowl is relatively narrow - 17.5mm at the top, 36mm deep, and has a somewhat tapered shape. A smoke lasts about 40 minutes or so - bowl dimensions and smoking time is something to consider before cutting wood. I would also be careful with wall thickness - better to be a bit thick than a bit thin.
Interesting thread here (but not made in the woods)...
http://bushcraftusa.com/forum/showt...es-Continually-Updated-Thread-Updated-7-25-12
