Bow 'n Drill Coal - Oh Wise Ones Please enlighten!

Q

Quirt

Joined
Oct 10, 2005
Messages
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Okay, got my bow 'n drill technique down well, no more flying spindles, bow moves smooth and level. I can create dust, lots of smoke but no coal.

I've tried many woods but finally read your advice and got a set of Popular spindle and fireboard. I've created quite a few piles of dust but it smokes for about 3 seconds after I've stopped and then finally goes out. No sustainable coal.

I've tried more pressure, less pressure, I've gone fast, slow. I've watched kgd's excellent two part you tube at least three times, read, and re-read Doc's excellent post (which should be a sticky) on how to build a bow set. Nada on the coal.

The dust is a dark brown almost black. The photos show it as pure black. It isn't but it is almost black and closer to black than brown. It will not stick together it generally falls apart. I keep thinking I'm using too much pressure but I've backed off as much as I think I can. I'm open to suggestions. I'm frustrated but darned if I'll quit!



 
It appears that you are quitting too soon. Once you have a nice pile of char like that, THAT'S when you need to bear down and put on the pressure and speed. The char traps the heat, IF you're putting heat into it.
 
One thing I would do is cut the notch deeper on the fire board so it is right to the bottom where the spindle rides. Also if you scape the blackened wood on the spindle with a knife to expose clean wood before you start again that might help. Also be really really careful when you get the ember as too much bumping around will break it up and it will go out. Good luck it is a great feeling when you get flames.
 
Quirt,

I'm by no means an expert in the use of the bow drill, but I've had success with it and am improving. I've included a video at the end of this post of my very first bow drill succcesses that highlights everything I was doing wrong before I finally succeeded. As you'll see, I made nearly every mistake possible before finally succeeding, but you will see some of why I finally got my fires.

From your photos, I can see a couple of problems:
First, as rcoulas said, your v-shaped notch needs to be cut deeper into the socket hole. You want the dust to begin collecting as soon as possible, not overheating and getting ground into too fine a dust. A large notch permits the dust to collect sooner and in greater quantity. The very tip of the v-shaped notch should just barely reach the center of the socket hole. I've found a 45-degree V works best.

Second, the dust you're producing is too fine and suspiciously dark. As you rightly noted, it's not clumping together as it should and that's the key. Color is not a very reliable indicator, but in my experience, dust that's so dark throughout AND fine and powdery, instead of clumpy and feathery, is dust that's been overheated - essentially already burned - and so it can't hold together and there's barely any combustible material left in it anyway, so it can't form a lasting coal. There's a way to test if the dust lacks combustible material. Put a match to it. If it doesn't catch on fire, the dust is no good and can't hold a coal because there was too much heat involved while producing it. A larger notch sometimes does the trick, permitting the dust to escape the socket before it's overheated and ground too fine.

You will need to keep trying, with various combinations of wood, and varying your speed and pressure until you get the right quality and quantity of dust forming in the notch. And the speed, duration and pressure you need to apply varies depending on the woods you use. I'm afraid this part is more practical art than rule-governed science. There's no quick and dirty rules here. Once you get your first coal, that's when you really start to get a better idea of what speed, pressure and duration of bowing are required for the type of wood you're using.

However, there is some good news: You can cheat. You should cheat! It will help you get those first few coals you need to get a better grasp of the speed, pressure, duration needed. What do I mean by cheating? Start by working with store-bought, kiln-dried wood. Cedar works well. This eliminates the problems attendant with wood you harvest yourself, such as: too much moisture in the wood, wood that is too resinous, a spindle that's too punky, etc.

Another good cheat, perhaps what you need most, is to use a frictionless bearing block instead of a rough rock or carved piece of wood. Use a hunk of smooth teflon with a shallow dimple drilled into it or use a wheel bearing from a skateboard or roller blade . Eliminating the friction between the top of the spindle and the bearing block will make bowing easier and faster, allowing heat and dust to built up quickly before you tire and before the bottom of the spindle and hearth socket get that hardened and polished look that results in overheating and fine overly ground up dust.

Here's the link to my video in the hope it will help and, I hope, encourage you to continue. And if you look in the description box below the video, you'll see some links I provide there to other very helpful videos by others that I found invaluable.

http://youtu.be/eBizmcn_X6w

Hope this helps and keep playin' with fire.
- Martin
 
Thanks guys...VA I've been watching as the dust piles up and when it appears to be approaching the top of the notch I start bearing down and go faster. Perhaps I'm not bearing down enough. I'll try that.

rcoulas, so cut the notch deeper or closer to the center of the hole? Is that what you mean? Also yes, I've been scraping the blackened wood off and reshaping the end of the spindle between each time. What you see is the shot of the board and spindle immediately following my last attempt.

Martin, thanks! I actually watched your video twice a week ago! I will take your advice and give it a try. I have a dandy rock as a socket but will try something slicker/freer on the next attempt. You guys rock!

Thanks for the feedback...I'm open to any/all feedback!!!
 
Another tip. At each start, your spindle should look like a new pencil, sharp and pointy on one end and an unused eraser on the other; by that I mean the down end should be anywhere from totally flat to a one-eighth to three-sixteenths inch radius or bevel around the edge. I use an old farrier's rasp to flaten the end. A charred end doesn't produce as much friction as a fresh end.
 
Quirt said:
Thanks guys...VA I've been watching as the dust piles up and when it appears to be approaching the top of the notch I start bearing down and go faster. Perhaps I'm not bearing down enough. I'll try that.

rcoulas, so cut the notch deeper or closer to the center of the hole? Is that what you mean? Also yes, I've been scraping the blackened wood off and reshaping the end of the spindle between each time. What you see is the shot of the board and spindle immediately following my last attempt.

Martin, thanks! I actually watched your video twice a week ago! I will take your advice and give it a try. I have a dandy rock as a socket but will try something slicker/freer on the next attempt. You guys rock!

Thanks for the feedback...I'm open to any/all feedback!!!
Click to expand...

Yes cut the notch just to the center and wider, it will be a big help. As mentioned one of the most important things when learning is to make sure your spindle, fire board and the material used under the fire board to catch the ember is dry.
 
I also use a "backcut" on the underside of the board. It allows your pile to be more conical, and stable.

And when you think you are about to collapse, you've drilled long enough.

Good luck, brother, success is just around the corner.

Moose
 
I store bough cedar board and a yucca spindle or yucca on yucca is a great place to start. Yucca burns at several hundred degrees less than many of the other types of wood people try to use. This is about the right time to go look for dried yucca stocks too. You can get a coal with yucca in 30 seconds or less once you figure out the right method. I've had good luck with maple on maple too, but it takes much longer than yucca and requires a little more speed and a lot more down pressure.

When you start just worry about warming up the drill and filling the notch with dust. Once it starts smoking to the point you know you have a coal then give it the devil and go and fast as you can until you can't go any more. That's how you get your first coal. After that you'll slowly figure out how to do it with less effort. :)
 
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