Questions from making my first bow

[rich59]

One too many Robin Hood films and I have cracked. Time to try this bow making thing. Well, actually I had already collected the materials before I saw the film, so I must have been well on the way.

You must understand that this is from first principles and I am very much a beginner.

I had noted when out with my niece that a local plantation of bamboo in the park had some good strong dead canes that seemed nice and springy. We came away with 3 about 7 feet long, each about as thick as my finger.

First I simply tied a piece of cotton string to each end of one bamboo using a clove hitch. For an ad hock arrow I grabbed one of my hand drills (elder) and about 12-15mm diameter. I notched the thicker end, pulled back and fired at my shed wall. Got a satisfying "thunk" and a mildly marked panel.

OK, so clove hitch will do until further notice? It seemed secure and tightened well. With bamboo the nobbly rings will probably keep it from sliding.

The next thought was - how can I get a bigger "thunk"? I tightened the string more so that the natural shape of the bow was ..... a little bowed. This got me a bigger "thunk". But I wanted more.

I had heard the phrase "draw weight" and not fully understood. Now with my hands on a bow it seemed like this must refer to how much weight would be used to bend the bow by gravity that I had done with my arms. How to measure that weight? Well I had some bathroom scales in the shed. A little thought and I came up with weighting the scales with a sack of charcoal and putting the bow round the sack and pulling upwards on the string and seeing how much weight came off the scales for the amount of bend I had put in the bow when firing an arrow. I found that I had about 5lb of draw weight (if that is the correct usage).

OK, so how to increase the draw weight?

How about 3 bamboos? I lashed my 3 bamboos together (2 one way round and the 3rd the other way round) with about 6- 8 simple knots along the length, reattached the string and tried again. First shot and the string broke. So I moved to a quite thick modern nylon parachord. No chance of that breaking? With this setup of 3 bamboos and thick cord I tried again. A bigger "Thunk"! A draw weight this time when measured of about 10 lb (not the 15 I had expected). I tightened the string more to make it a natural D shape and got a "THunk". So I was getting better.

Then I thought, why use the whole length of the bow when I would get more bend and therefore more tension from a shorter length. So I retied one end a couple of feet down the length of the bow so that I had an effective bow of about 5 feet. Pulling on this gave a satisfying tension. I could not measure it on the scales as I was exceeding the weight of the charcoal bag. When I fired with this I got a "THUnk". Coming along.

I did note that the arrow tended to twist in the air and so did not hit the wall perfectly in the line of flight.

Well, that is about it for now. More another day.

But I have some questions.

Why do you thin the ends of a bow? I suspect it is to get an even bend. But why do you want an even bend? In my setup the thickness of the bow would be even down the length, with no significant tapering. I presume the middle did bend most but why would it?

Is it a problem having a thick bow string?

Could I solve the twisting in flight by making a bridge in the middle of my multi stick bamboo bow so that the arrow passed in between the two halves?

Are shorter bows more efficient than long ones as I seemed to find?

 

[Bisamratte]

I know nothing about bows, but it realy sounds like fun

I know where some bamboo grows.......




I keep getting carried away with these smilies

 

[sam_acw]

I think the twisting in the air you describe is probably due to the stiffness of what arrow you are shooting. The arrow curves around the bow as it is fired and will tend to push away from you if it is too stiff or pull the other way if it isn't stiff enough. At least I think that's the way it goes.

 

[bent-stick]

Bamboo is flexiible and elastic so you can get away with quite a lot when you are working with it and you just reinvented the panda bow or bundle bow. Normally you'd reduce the number of canes as you get towards the end.

Just about anything will work for a knot, Saxton Pope describes a couple of turns and a half hitch to secure the string. If you want tso be proper then you can use a timber hitch or bowyers knot (over, round and through and through) which will give you something that will slip tight and stay put.

The reason for the tapering in bows is to get a nice arc that spreads the stress evenly through the limb. If you tried what you did with just about anything except bamboo you would probably find your 'plank' broke in the middle unless it was pretty thin when compared to it's length.. The bow hand it a bit like a pivot and most of the stress is there.

So first of all you'd need to reiforce the handle. Then you'd find that it would break at the junction between the handle and the limbs because all you've done is move the pivot points. Pretty soon you'd find that by reinforcing up and up the limb and you invented a bow that is tapered from limb to handle, Only about 7000 years or so too late

There are a lot of refinements, for example width vs thickness and leaving the tips a bit narrower and thidker to reduce tha mass in the bit that moves the furthest to optimise the amount of energy that you transfer to the arrow and with a bit of experimentation you'll arrive at the modern flatbow design.

Then you can start playing around with reflex and deflex and you'll come up with the modern recurve.

It's all fun stuff. And addictive, ask 'er indoors

 

[Snufkin]

Bent stick covered most points well. As to having a thick string it isn't really a problem but a lower weight string accelerates faster but often creates more noise. It isn't a major difference, only matters if you are trying to squeeze the maximun performance out of your bow.

 

[bent-stick]

The other prblem with a thick string is that you have a problem making a nock that grips it so you are limited to a pinch grip. I've seen a 50 lb amazonian bow pulled with 2 fingers and a pinch but there's always the danger of a dodgy loose because you have to let go of the string with yuor ring and middle fingers and let the arrow be pulled out of the forefinger and thumb pinch.

My panda bow has a paracord string.

 

[Woods Wanderer]

nothch the thin end

 

[stovie]

"Could I solve the twisting in flight by making a bridge in the middle of my multi stick bamboo bow so that the arrow passed in between the two halves?"

You could always lash a couple of pigeon tail feathers to the end of the arrow shaft and have flights, like this below as found in TBB Vol I.

What you describe is the archers paradox, shooting an arrow 'round a corner but wanting it to fly straight. cant the bow 10-15 degrees off perpendicular and this will increase the flight accuracy quite dramatically.

 

[bcraft]

Hi i recently made a bamboo bow following the one of the articles on this website, but when i tried to attach the string to it is snapped. did i do anything rong? or was it just the type of bamboo?

 

[bent-stick]

Some of the garden centre bamboo is not perfect, It has probably been hanging around out in the rain for yonks. Also you need to look at it for kinks and splits. I bend each cane individually and it will show up the weak points,

And get the binding TIGHT so all the sticks work together.

Don't give up, and after all if one stick breaks you only need to replace that one and not the whole bow

 

[bcraft]

Thanks bent-stick i'll try again. do u have any idea what to tye the bamboo sticks together with, last time i used thin nylon fishing line but it just kept slipping
thanks

 

[gregorach]

Stovie did a number of good threads on bamboo bow making - if I remember, he was using duct tape initially.

 

[bent-stick]

I use Jute Fillis from the same garden centre as the canes. One binding 2" long every 6" or so.

The natural fibres are less likely to slip around than fishing line etc. If you are using manmade finish the whipping with a surgeons knot and not just a reef knot just to make sure.

It is possible to use tape too. I tried one with some cheapo gaffer style tape from the 99p shop. The only problem with that is that it isn't as waterproof as I'd like it to be.

Make sure your bow is long enough. I have arms like an ape so my middle canes are 7ft.

(edit: greg beat me to it...)

 

[stovie]

Stovie did a number of good threads on bamboo bow making - if I remember, he was using duct tape initially.

Try these old threads. It has to be said that I kind of "went to town" with the finish. It's not absolutely necessary to lash from tip to tip, but it made for a nice look

First Boo Bow

Boo bow 2

Stovie Jrs Boo bow

Bamboo Bow 3

Duct tape makes good cheap fletchings too...

 

[bcraft]

Thxs loads thats really helped, a quick question does the varnish have to be a special type and also could u explain again how u done the notches.

Thx

 

[stovie]

Thxs loads thats really helped, a quick question does the varnish have to be a special type and also could u explain again how u done the notches.

Thx

Any varnish that takes your fancy will do.

Nocks are created by building up cordage and using plenty of wood glue as you wrap..like this below

 

[bcraft]

Hi its me again i intend to make the bamboo bow but just wondered wether (it would be my first bow)it was the rit won to start of with could u recomend a decent bow to start of with.

 

[stovie]

Hi its me again i intend to make the bamboo bow but just wondered wether (it would be my first bow)it was the rit won to start of with could u recomend a decent bow to start of with.

This is simple and takes very little time. It's as good a place to start as any. When you've caught the bug, who knows...

 

[bcraft]

Thx ive been traileing through some of the bows uve made and their amazing!!!!!!!!!! how did u get to be so good and wat was the one u started of with first thx

 

[bcraft]

Hi ive been looking through some touritals of bow making and is it possible to make them from flat boards used by builders