Thursday, 16 February 2017

Buddleia Explodes!

Having started with the left limb stiff, I over compensated and it was then a tad weak, but I was easing off the right limb and teasing it back.
I'd got it to about 40# at 23" when it went bang, failing a big knobbly knot, hardly surprising. Just a bit of fun trying out a new wood.
The wood is OK, it's the regular big knobbly knots that are problematic as they are rather pithy and weak on the belly and are a weak point on the back.
Pics sow the break, note the filled knot on the belly, it was a large porous area of bark like material.
The tiller wasn't too bad, the grip could have flexed more and the right limb was still a tad stiff.
Here's the video of it going bang :)
https://www.youtube.com/watch?v=dfrpNkQME04




Wednesday, 15 February 2017

Buddleia

Otherwise known as the Butterfly Bush, We pruned one of these back in the autumn of 2014 and there was a nice straight section which I saved to try as a bow wood.
I couldn't get any opinion on it other than "try it and see" so here goes. I suspect it may be a bit brittle as the dead wood on the shrub is V brittle, but so far it seems fairly stiff and quite hard, with some attractive colour.
I'll show the first try on the tiller as it is V bad and shows the left limb very stiff, the second shot is after I've done a good bit of work on that left limb and faded it back into the grip more (it will flex in the grip when finished). The stave is only 51" long, with a nice waggle in one end,
The bark, which is similar to that of Elder has been left on and is making ominous cracking sounds.
Looks reasonable now, gotta get the grip moving moreand the right outer limb.
I make edit together a video showing how the tiller progresses... we'll see.
I'll probably aim for 40# at 24-25" if it doesn't explode first.

Monday, 13 February 2017

Tarting up Mr Wonky

I thought I'd finish up the Wonky Warbow with an arrow plate, one reason being to cover a slightly narrow bit at the end of the splice. The billets weren't necessarilly going to end up as a warbow, but once I'd made the decision to go for 100# I left the stave a wide as possible, you'll see the narrowing at the end of the splice on one of the other pics (the one with the funny little face!).
Had been hoping it would get shot yesterday, but was overtaken by events, hopefully it will get an outing at the weekend if the flood plain is still dry enough. On a plus note I just heard from JT who shot one of my other bows at the shoot and got 301 yards for the flight shot, winning that part of the shoot. I think we're still learning about flight arrows, it will be interesting to see what Mr Wonky can do with a flight arrow, we know it's not all about poundage.

 Out of interest, the glue area of the Z splice is about  3 x 4.5" times 1.5 inches deep. That comes out at 20.25 square inches of glue area!

Wednesday, 8 February 2017

Reflexed Tips and the Magic Brick

I had someone ask why I used a hot air gun and oil to reflex the tips of the Wonky Warbow rather than steam.
Here are some pics showing how I did it and a list of pros and cons.
Pros:-
1. Dry heat is quicker.
2. You can see what is happening while you are applying the heat.
3. The heat can be taken up to about 200C giving some tempering as well as plasticising the wood. Being hotter it penetrates quicker.
4. You don't have to worry about getting from the steam onto a jig quickly.
5. Gentle even pressure can be applied and the wood allowed to relax into the bend at it's own pace by using the "magic brick".
6. Getting the wood hotter seems to set in the bend and have less bounce back than with steam.
Cons:-
1, The wood can get over heated and scorched.
2, Heat can leak round to the back and effect the delicate sapwood.
3. You can't leave it and have to hold the hot air gun. Whereas you can leave it steaming for half an hour or longer with no problem.

I've used both, I just went for the hot air gun this time (with sunflower oil brushed onto it) so I could get both ends done in the evening and then leave it overnight.

Note the side cheeks used to keep the heat on the belly, the back and sides were also protected with a few layers of masking tape.
With the brick pulling down on the bow, I could see it starting to pull slowly down after less than about 5 minutes of heat!

Reasons for reflexing! (A response to the explain more and the comment)
In this case it is to compensate for the deflex in the bow and to bring the tips back in line with the grip. The more technical aspects of the deflex/reflex design found in modern bows is basically down to improving the force/draw curve of the bow and making maximum use of the materials.
The maths and physics is beyond me, but I have good ways to visualize it and can maybe explain it.
There are several factors coming into play.
Let's consider a simple longbow, if we reflex the tips 2" this will make it require more force to pull the tips back to brace it, this will add early draw weight and give a faster bow... but we may overstrain the wood if we try and pull it back as far as we did before. So what if we deflex the middle of the bow by 2" we are back to where we started but has it made any difference? Well it turns out it has! The angle that the string pulls back on the tips has changed throughout the draw and this makes a difference.... why?
Well imagine a beam sticking out of a wall with a length of string dangling from it. If you want to bend the beam you'd pull straight down at right angles, if instead you angle the string back towards the wall (or away from it) you can't exert the same bending force even though you are pulling just as hard. Take it to the limit and pull the string inline with the beam, you are now exerting no bending force at all! You can pull as hard as you like but you are effectively just trying to stretch the beam not bend it.
That's what happens with a short bow at a long draw, the tips are starting to pull back parallel to the arrow and it becomes harder to pull than would be expected, this is often called "stacking".
Taken to extremes, reflex or recurve can uncoil as the bow is draw effectively lengthening the limbs as the bow is drawn and giving more leverage. This effect is utilized by the cams in a compound and by the levers Asiatic style composite bows which tend to be short, the characteristics of horn and sinew also accounts for their extreme shape.


Tuesday, 7 February 2017

Wonky Warbow Video


I've had it back to 32" draw at 100#.
The tips have been lightly reflexed using a hot air gun.
Here's the youtube video:-
the bow has a fiar bit of lateral waggle too, you'll see I've done the horn nocks, just got to make a decent string now.


Sunday, 5 February 2017

Shooting a Few Arrows

I went down to the flood plain with my mate JT . He wanted to warm up a bit for a rove next week and try a few different bows and arrows. I shot my 80# @32".
He was hoping to get the 150# Yew back to near full draw, but it was a bit chilly and despite warming up on some other bows he wasn't quite there. Once the weather warms up and he's back to regular shooting he'll get on top of it. He had a look at the wonky warbow too.
The field was surprisingly dry, I'd checked it out yesterday and the river level had dropped a few inches since then.
The big surprize was some flight arrows, JT had 3 or 4 different sets, made by different arrowsmiths (none of mine). Some flew further than others, but two were totally bonkers, I've never seen the like except when as a kid I shot a bit of broken stick from a crossbow, The arrows took off, turned hard right, nose dived, then climbed again in almost a corkscrew manner, veering about 20 yards off line, before calming back down and sticking in the mud. He tried 'em from three different bows including my 80#. Looking at them, I think the problem was the point of balance was only about 1/8" in front of the geometric centre, add to this tiny fletchings and very stiff shafts and you ended up with arrows that fly like some of those early rocket launches that went wrong! I reckon if the back ends are tapered some more, that will move the weight forward and straighten 'em up. Out of about 8 shots with the 2 dodgy arrows we got one clean flight.
Hickman's experiments worked out that the cenre of gravity should be about 40% along the shaft (measured from the point). This article has some good info and references Hickmans work.
http://www.second-opinions.co.uk/flight-arrows.html#.WJhgdFOLTIU
I might see if I can get the wonky warbow ready for next week so he can have a go with it. Watch this space.

Thursday, 2 February 2017

Mrs Deers Ears! And Other Stuff

I've had a busy few days.
Emily Cat jumped onto the Deer sculpture that I made for my wife over 10 years ago, as she climbed onto the ear it fell off, as indeed did the cat!
So that was one more job taken into the garage for repair, it was interesting to look closely at the ear as it has a nice little patch of lichen growing on it to match the pale lichen growing Mrs Deer's nose.
I had to get that job done and out of the way to make way for some Yew, as I'd been put in contact with someone 30 minutes drive from me who'd cut some in the summer (thanks Luca!) It had been lying on the ground but still looked pretty good as it was at the top of a slope which was fairly well drained. Even if the sap wood had started to rot I was happy to get some decent heartwood for bamboo backed Yew bows. There was also a bigger log, which was too big to get on the car, I'll go back next week and the guy will run his chainsaw down the length to make it more manageable.
We got two decent logs strapped ont the roof rack. The longer log was about 12' long but I managed to run it through the bandsaw on my own using a roller stand to support one end as I fed it carefully through. Once it was half way I moved the roller stand to the other side and continued. I could have trimmed the length to give 8' and 4' for billets, but I thought it was better to leave it full length for now so I could get the best out of it once it's had some time to season and loose some weight. (Easier to handle then).
The shorter log was a bit knotty on one side but the other has the makings of a nice primitive. I didn't have much room on my shelves to store the logs, so I set to sorting out all my staves, I got rid of a couple of no-hopers and trimmed a few down to almost roughed out dimensions, a bit of reorganisation made room for the new stuff.
My general philosophy is to bring in good stuff and throw out the bad, that way my stash of timber slowly inproves in quality, whilst maintaining a reasonably constant quantity. Mind, I'm still using some timber that other people would consider too iffy for bows, but I enjoy the challenge.

Whilst shooting in the 45# @ 30" bow (which has now been collected) I noticed the arrows pretty much going straight through the boss. The pics show it braced and unbraced, where you can see it has retained some reflex, nice!
Time to invest £95 in a new boss, it's rather a lot, but considering the last one was made of glued up packing foam from the council rubbish tip, and had lasted about 10 years, I felt I could justify it. It should arrive tommorrow.
Talking of the rubbish tip, I've just come back from taking the old target and scrap timber there. Whilst I was unloading I saw a guy unloading a leather sofa, Another tip user lent me his knife and I cut out two nice squares of leather, it's a pale greeny beigey turquoise (I expect ladies have a fancy name for this colour rather than "snot" which is how my son described it). Anyhow, you can't have too much leather as it doesn't take up much room, unlike logs!