The first thing I need to find is a suitable piece of stick, preferably seasoned, but in this case I used a green stick. The problem with using green wood is the fluff that's left in the chamber when you drill it out. I'm sure that I can sort out the problem with a piece of hot wire later. I carefully drilled out the chamber with an 8mm bit and followed it up with a 10mm. The diameter and length of the chamber dictates the pitch of the whistle... Once I've finished drilling out the stick I need to measure with my finger where to place the Window and Lip... About a thumbs width from the drilled end will suffice... I start with a cut straight down... And then a cut on the diagonal to meet it... I keep going until I reach this point... Now....Any amount of blowing at this point will only produce a red face. So I need to make the Fipple... Don't laugh....That's what it's called..... I quartered a short piece of stick and started whittling a dowel with a flat edge... Here I am with work in progress... I keep trying it for size as I go... What I needed was an interference fit, somewhere between staying put and splitting the whistle was fine... Push the Fipple in until it nearly reaches the window... At this point I gave the whistle a few blasts just to check it was all hunky dory.... I used the flame of a lighter to singe away the furry bits....Next time I will use a seasoned stick... When I was happy with the whole arrangement I cut of the tail end of the Fipple... Now...The Fipple may stay put, but just to be on the safe side I would recommend making up some glue. Easily done with some Bear grease, pine resin and charcoal. Now...In Devon we've got plenty of Manglewurzles but we're a bit short on Bears, so I would advise nipping off to the ironmongers and purchasing a wood glue of your choice, remembering that you will have to put the glued end in your mouth... And there we are...One perfectly formed wooden whistle... Well...Perfectly formed after a bit of carving anyway... The International Mountain Distress Signal is 6 rapid signals (by whistle, torch, shout, etc.) repeated at one minute intervals until you are located. Just in case my old mates come looking... ENJOY...