Monday, 5 December 2016

Tinkering

I've been messing about trying to get an archer automaton mechanism working, just a realistic draw and loose initially. I started with some tin from an old biscuit tin and then moved onto plywood. The draw isn't too difficult but the loose is tricky. I'm following my engineering of simplicity, simplicity and trial and error.
Any how here's a video of it:-
https://www.youtube.com/watch?v=udnK4SXUtBY

I've been doing some online research too and they mention Basswood as being good for carving, I though... "Oh, I'll have to get some of that"... them I thought, "Don't be a twonk, I have all sorts of wood that's good for carving already!" Hazel, Cherry, Lemon wood is prob' good too. Any how, I split some cherry that has been outside for over a year from when trimmed on of the Cherry trees. That led to more work like cleaning out the dust extractor and changing bandsaw blades.The cherry is too wet to use now, but it's been cut down to useful sized pieces. I have some already seasoned lying about and I've been planning the next stage of the automaton. I want it to grab on to the string automatically, I don't mind having to manually load the arrow tho'.
There are some incredible Japanese ones on youtube, but I think they were made by a skilled automaton maker rather than an archer as the bow drawing action is all wrong! That is to say the draw is all accomplished by pushing the bow hand forward and there is no drawing back of the string. They are still fantastic works of skill and artistry though.

Thursday, 1 December 2016

The Sun is Shining

Ha, I've cheered up a bit after the bow explosion, I got a nice E-mail from the guy for whom I was making it.
I've tidied up the garage and cleared out a load of mess from the summer house job. I had a quick shufti at my staves too, there is some good stuff which will be ready for next summer.
I might have a bit of a tinker with a project I've been thinking about, making an archer automaton... it's a bit chilly in the garage, but I might have a little try out with some tin plate from old biscuit tins etc (I keep all that stuff as it's great material) and a soldering iron. If it warms up a bit I may sort the staves.... a stave falling on your head in clod weather just hurts too much!

Wednesday, 30 November 2016

Damn it Exploded

I'm rather fed up as the bow was looking really good and wasn't far off full draw. I was studying the tiller flexing it back and forth, I wanted to take it a tad over 45# just to see where it was flexing and how close I was to 28". After all it had been pulled to 50# before.
BANG... Predictably it went at one of the feature knots, but the break/split spread along most of the limb, so it was all rather stressed.

In an effort to learn as much as possible about the break, I sawed through the limb just the grip side of the break, it shows the cross section is good with a nice proportion of sapwood, although there is some blue discolouration in the sapwood and on the heart/sap boundary (see dark streaks where it has split in the bottom pic)

One has to be philosophical. At least it didn't break in the hand at full draw, but it's a little upsetting after the amount of painstaking work I'd put in. That's why character bows are so highly prized, they look good and are rare due to the difficulty of creating them.
On the plus side, the spliced tips didn't break and the grip and lower limb are ok so maybe they can become a novelty Frankenbow at some point spliced onto a longbow limb or something.
I'll have to tell the guy I was making
it for that he won't be getting a bow... mind he's not lost anything, although I'm sure he'll be disappointing.
Dunno what I'll pick up next and when... maybe something simpler!

Monday, 28 November 2016

24" Draw and Closing...

The character primitive is getting very close now, the lower limb is bending more in it's outer 1/3 and I've been cleaning up the belly with a scraper.

The big feature knot hole area is still a tad stiff, but I wondered how sound it is on the belly, after all the hole goes in very deep from the back and I've taken a good bit off the belly. I did some gentle probing and sure enough there was very little wood there.
The big question is do I open it out an leave it as a feature hole or do I fill it on the belly side down to about half the limb dept to prevent it crushing an pinching? I'll probably fill it. Feature holes in Osage are quite common but it's a much denser wood and I'd rather err on the side of security than style.
The work I've done on the back is paying dividends as it is beginning to look really good now, photos rarely do a bow justice, so I'll wait until it's finally finished before trying to show it off.
Mean while here's a pic showing working on the belly and the feature knot.

Sunday, 27 November 2016

Getting There

I'm making good progress now and the Yew primitive character bow is really looking and feeling like a bow.
It's at a decent brace height (not quite full brace) and I've been going over it feeling for thick spots and easing off round the knots, tidying up the back and when the bend is even I've been rasping evenly along the belly to bring down the weight a bit at a time. I've been narrowing it slightly and rounding the edges too, allowing the odd small knot to get rasped off the edge.
It's pulling 50# at about 22" now, so getting pretty close, time to slow down a bit more and to really look at the finish and detail as I continue teasing it back.
You may see in the pics that the right limb is bending more, (that's the one I've just been working on) and the left is stiff in the outer 1/3 so I need to ease off the left a bit now. It's important to maintain the tiller as it's teased back the last few inches, and you have to remember that the the last 6" of draw only amounts to 2" of extra tip deflection, so it has to be right now, if it's to be right at full draw.
It really shows the value of taking video and and then looking at the still, I hadn't noticed the stiff outer on the left limb until I saw the picture. You can't beat being able to sit back and have a good look, as you don't want to be holding a bow at full weight for any longer than necessary especially if it isn't fully tillered.
I sometimes think maybe I maybe get too fussy too early, but experience tells me if you try to rough it out too close to final dimensions and try to rush the early work, it can all run away with you and you end up under weight.
It's not a race, little and often, slow and steady.
I've just been easing off the belly of that left limb tip, there's a pair of knots showing on the belly which looked fairly solid, but as I rasped down I could see a slight black line round one of them, as I picked at it with my sharpened needle file it just crumbled away opening up to form a hole which goes right through to a pin prick hole in the back. I've cleaned it out and filled it with Yew dust/epoxy mix. It just goes to show that you can't trust a knot to be solid, just because it looks solid on the surface.

I've done a bit of Youtube video showing how I work down the sapwood, tidying it up as I progress, it's a bit of technique I've not seen explained or shown before. I don't claim it's "right" clever or funny, it's just what I do and may be useful to anyone scared of working down Yew sapwood!
https://www.youtube.com/watch?v=ElP8l396qxM


Friday, 25 November 2016

Back a Little Further

The Yew primitive character bow is coming back by degrees. I've made a little video showing some of the features and it pulling to about 17":-
https://youtu.be/w1X7LCgaMOU

Some bows make you nervous and some fill you with confidence, mind you just don't know in reality until it's fully drawn. I've got a nice even bend and I'm working with rasp and scraper now easing off any thick areas and tidying up the back around the knots. I've got it braced a bit higher now and have been working on the upper limb. It's pulling about 45# at 15" which is 3 pounds per inch (45/15) this gives just a rough and ready figure when multiplied to 28" draw of 84 pounds draw weight! This gives some idea of how much wood I've got to remove, taking wood off the thickness has much more effect that taking it off the width. In fact, theoretically I could saw the bow down the centre line and make two bows each of half the width and 42# draw weight.
The main reason for not drastically reducing the width is that I'd have proportionally more knots on the back. E.G:- A 7mm wide hole in the back of a 40mm wide bow is a smaller proportion of the width than a 7mm hole in a 20mm wide bow.
Also a thinner wider bow is less stressed than a thicker narrower, the problem with reducing thickness is that I don't want to remove all the heartwood, or conversely break through the sapwood on the back.
So it's slow and steady, a little off here, a little off there, and I'm taking the working limb further in towards the grip EG:- effectively shortenning the grip and making the fade from grip to limb a little quicker. An extra mm of movement at the root of the limb will give maybe 10mm at the tip, and 10mm at the tip equates to about 300mm extra draw.
In terms of width I can gradually narrow and shape it to an elegant leaf profile which will also be easing off the weigh and increasing the draw.
You can see that despite having a long way to go, small changes and tweaks will ease it inexorably back towards full draw. The lower limbs needs some work, by which time I'll be closer to 20" draw... slow and steady wins the day.

Thursday, 24 November 2016

First Flexing at a low Brace for the Character Primitive

I've got it to a low brace and looking fairly even at about 45#. It's steady work from now on to slowly remove wood from the belly keeping the tiller good and easing the draw length back whilst holding the draw weight at 45-50#.
I'll need to keep a close eye on the knotty areas, they will have to do some work and contribute to the flexing of the bow, but mustn't be over stressed. I'll also be cleaning up the back getting it close to a single growth ring where appropriate.
Here's a V short video of it on the tiller.
https://youtu.be/nnNu0NBm1WQ
Bit of a rant! :-
Bad Design, we bought a Bosch vacuum cleaner about a year ago because the Dyson is so bloody noisy. The reviews were good, and it is lovely and quiet...until... it's just started to fail because it's "lifetime filter" is so clogged it needs ripping open and washing out.
It has a clacker mechansim that is supposed to rattle out the dust when you rotate a knob. One of the clacker fins has snapped off because it wasn't designed by a bowyer. It has no taper on it and so it snapped off at the root... I'm sure it was fine on the CAD system (sigh), anyhow I'll clean it out and rebuild it, meanwhile I'm getting subjected to a noise roughly equivalent to shoving my head up a jet engine.
Fair do's to them, I posted this rant on their Facebook page, they have responded V quickly and will send a new filter.