Jack I watched a 'proper bushcraft' bowdrill being used for the first time a couple of months ago and was appalled at the amount of effort involved. I reckon they make life difficult for themselves.
Take a stick about 25 to 30] cms long and about 4 cms diameter; something like hazel, alder, chestnut, willow..... now saw off 6 or 7 cms of it. This will become your bearing block.
The longer piece needs to be sawn around about 4cms from one end but only inwards about 1 cm. Now, using your knife cut down from the end (as though battoning) into that saw cut all around. You are aiming to make a round peg just less than 1.5cm in diameter. When you've done that now gouge out a corresponding hollow from the bearing block with your knife....you'll probably need to sharpen the blade edge when you're done but the block you make will last for ages. (Bu88er this *burning it afterwards*,

get the hang of using it first

) carve around the top edge of the bearing block until you've got a smooth domed shape that's comfortable in the palm of your hand.
Now for the actual spindle tip. Aim for a conical, sharpened pencil shape first and then create a straight *lead* about the same thickness as the spike you carved at the other end.
Next the middle bit. Gently shape it out so that the bow string doesn't slide too far up or down, a smooth curved waist is all that's needed not a channel. Sometimes removing the bark all around this bit is all that's needed.
Use wax, fat, (juniper berries are surprisingly waxy, but a candle will do fine) and put a bit into the bearing block. Insert peg, it ought to turn freely and not bind. If it does you'll just heat up your hand not the hearth and you need to smooth it down a bit more.
This set up focuses all of your effort on the small spindle tip, and cuts down on all of the bits that move out of line. Make your hearth as usual and *burn in*.
I was taught that this type of fire bow/spindle is a copy of one found in Tutankhamun's tomb, though that one was bound with copper and had removable spindle tips.
Several of the members of bcuk will testify that at the Crannog firemaking is demonstrated regularly, and easily, by various members of staff and that the general public are not only welcome to have a go but in many cases manage it themselves with relative ease.This is the type of bowdrill set up used there.
Bowsayer and me made a set like this last week in the back garden in the time it took to drink a cup of tea so it's not that much effort. I have made the set using a stick about 3cms diameter and it worked fine, you could probably get away with just using a thin 1cm stick that fits into the peg style bearing block too so long as the socket was well waxed; and it would cut down on the carving time. Think I'm going to go and play....
Images at :-
http://www.seamstimeless.pwp.blueyonder.co.uk/
p.s. If you have trouble getting timber, check that your parents will agree to having your address given by pm, and I'm sure that there are people on the list who will happily send you suitable bits.
Cheers,
Toddy