Lighting a fire by friction is perhaps the most iconic skill within bushcraft, almost a rite of passage and nobody ever forgets their first ember. Which raises an important point, whilst we all talk about fire by friction, this method doesn’t produce a flame in and of itself – it produces an ember, which when added to a suitable tinder bundle can be blown into a flame.
This is Part 1 of a 2 part article on fire by friction and covers the different parts of a fire by friction set, how to make one and what materials to use. Part 2 is concerned with bedding in the set and getting the ember.
There are 5 component parts to the fire bow set, these are:
- Hearth board,
- Bearing block,
- Ember pan.
The bow, as a rule of thumb, should reach from the centre of your chest to your finger tips. Make sure it isn’t too thick as this will mean that the bow is heavy, which in turn can make it unwieldy and tire your arm; maybe 2 or 3cm in diameter. A slight curve is an advantage, as is ‘Y’ shape at one end. Make sure that the bow is well balanced. If it is heavier at one end, use that end as the ‘handle’ end.
I tend to make my bows from a straight piece of green hazel that I then gently bend into a curve; I then tie them off and leave them to season. Once they’ve dried out they retain their curved shape. If you need to make a bow whilst your in the woods, you’ll need to find a branch that is already curved.
You can drill a hole at the handle end to attach the cord, otherwise cut a notch in the bow a little under a hands width along; use a knot that won’t come undone easily. By tying the string just under a hands width from the end you can use your index finger to apply a little extra tension to the string when bowing. On the other end, attach the cord using a knot you can undo to adjust the tension in the cord (I use the same round turn and 2 half hitches I use when putting up a tarp and hammock).
The string itself needs to be strong, not prone to stretching and reasonably thick. Paracord is ok for this task; we tend to use 4mm cord that I got from a chandler. A bootlace will do in an emergency. Make sure that the string is taut when attached to the bow, but that the spindle can be attached.
Hearth Board & Spindle
There are least 2 different approaches to making your hearth board and spindle.
- Make them both from the same piece of wood.
- Make them from different pieces of wood.
Whichever approach you go for, the hearth board and spindle have to be made from seasoned wood. You will need to find standing dead wood to do this.
Making them from different woods
Many people like this approach and certainly one big advantage is that by carefully selecting your materials you are setting yourself up to succeed, so it is a good way to develop and hone your skills in fire by friction when you’re first learning.
- The spindle should be harder than the hearth board.
- You can use a branch that is already the right diameter (about the same as your middle finger).
- My preference is hazel although ash, sycamore and birch all work well for a spindle.
Making them from the same piece of wood
This is possibly a more difficult approach when you’re first learning fire by friction, but one that you should aim towards as your skill level increases. This approach helps you to accomplish 2 things;
- You remove a variable from a process where lots of things have to be right,
- You save time; you only need to find one piece of wood to use.
Making the hearth
The hearth board is the piece of wood that you’re going to drill into. As I said earlier, this needs to be taken from standing dead wood. A good piece of wood to construct a hearth from will be around 10cm in diameter.
- Cut a section up to 30cm long. Avoid pieces of wood that are knotty.
- Split the wood down its length in the centre. Take one piece and split it again so you end up with a board about as thick as your middle finger.
- Remove any remaining bark and ensure both sides of the block are flat and relatively smooth.
- Remove any pith that might be present.
- Don’t allow any moisture to come into contact with the hearth.
Making the spindle
People have their own preferences when it comes to the length and diameter of their spindle. Some people work with shorter, some with thinner, others longer. You will need to experiment and find your own favourite, but as a starting point, go with a spindle the same diameter as your middle finger and about 20cm long.
Bear in mind that whatever you do there are trade-offs:
- The thinner the spindle the more RPMs can be achieved but less friction,
- The thicker the spindle the less RPMs but more friction (therefore more strength is needed),
- The longer the spindle the longer it will last, but it will be more prone to wobbling about in the hole,
- The shorter the spindle the less it should wobble but the quicker it will be used up.
- Many of our students have told us that a longer spindle allows them to keep their back upright when they are drilling, so they can use their body weight to apply downwards pressure instead of their arm..
If you’re making your spindle from a piece of hazel, all you need to do is find a straight piece that’s the right diameter and length and point the ends (see drawings opposite). Ash, birch and sycamore all produce long straight stems that can be used as a spindle.
If you’re making your hearth board and spindle from the same piece of wood, you’ll need to take the other half of the wood you used to make your hearth board and split it into 2 triangular shaped sections. Axe off the corners and start to work it into a cylinder shape. At some point you are likely to swap the axe for a knife to continue. The spindle needs to be cylindrical, but not to calliper type tolerances; some tools marks will give the cord some grip.
The spindle should have a sharp taper at the top (almost like a pencil) and a much smaller, bowl like, one at the bottom so that the friction is generated between the spindle and the hearth and not the spindle and the bearing block.
A sharp taper at the top also means that as wood is worn away during the process of bowing, there is still less wood in contact at the top of the spindle and thus less friction..
The bearing block is best made from standing deadwood. The diameter is dependent on the size of your hand; the bearing block should sit comfortably in your palm. I tend to use a dense wood for the bearing block, so something like hornbeam is ideal.
The ember pan can be taken from an off cut produced when making the hearth, just make sure that it is bone dry.
Selecting the Wood
The table below categorises various wood in terms of their relative ease to make an ember when used as the hearth board. Feel free to disagree with this (in fact, please add your thoughts in the comments section below), but it is based on our experience. Also note that this list is far from exhaustive.
|Horse chestnut||Western Red Cedar||Hawthorn|
Here’s a video we made back in the spring of 2012. It covers making a spindle and hearth board from a piece of sycamore and also shows me bedding in that same set. I cover posture and bedding in the set in more detail in Part 2 of this article. Note that the spindle I make in the video is much bigger in diameter than what I make now, I’m always fine tuning how I do things.
If you want to join us to learn fire by friction, then take a look at our Institute for Outdoor Learning course. You can find loads of photos from this course, plus all our others, on our Facebook page.