Tuesday, 29 November 2011


I phoned the vet' this morning and they said the Woodpecker had died.
At least it wasn't got by a dog, fox or squirrel, it was an adult bird so maybe had just reached the end of the line, happens to us all eventually, and in fact I'm off to a funeral this afternoon.
Oh well, carry on.
I've put up another two shelves for my staves, I was rather pleased that I got the shelf brackets free. Last time I was at the Council rubbish tip I noticed a chap heading towards the scrap metal skip with a plastic bag full of shelf brackets, I caught his eye, nodded at the open boot of my car and said "lob 'em in there", he grinned and lobbed 'em in.
Recycling at it's best!

Monday, 28 November 2011

Green Woodpecker

I was walking in the woods going to collect some fallen Hawthorn and Maple which I'd spotted earlier. As I approached a huge recently fallen Oak with a big hollowed out base I saw a green woodpecker flutter around the base. It didn't fly away, and as I crept closer I realised it something wasn't right, as I went round the back it went round the other side and eventually down inside and hid down in a root cavity. I took my fleece off and laid it on the ground and gently reached in and cupped my hand round him and lifted him out (dunno if it was a him, it just seems right!) I wrapped him up in the fleece, warm dark and cosy.
I'm aware that well meaning amateurs can do more harm than good, so I phoned my wife and asked her to phone the RSPCA for advice and to ring back.
They said that if I could pick it up, it probably wouldn't survive anyway, but if we took it to a vet' they treat wild animals free of charge.

Once home we put him in a box, the pic shows what a handsome fellow he is.
I drove him up to the vets where they said they'd phone one of their bird specialists to come and collect him later. I was tempted to give my phone number so I could follow up and see how he did, but decided against it.
It was a good day for wildlife as I spotted a kingfisher by the brook on the way back too. Here's a pic of the logs I collected, the big one is the Maple. I used my wheeled dolly to drag it out of the woods.

Sunday, 27 November 2011

Tidying Up and a Wasp

I'm running out of room for my logs and staves so I've put up another couple of shelves.
The work entailed clearing out a load of gardening tools, pots, netting, string canes etc amongst which was a dopey wasp settling down for winter. The stripey git stung my finger and it's still feeling a bit itchy 2 days later.
I've got my timber all up out of the way on shelves now, a lot of it isn't the finest quality, but a stave on the shelf is worth two in the woods.
I'm also planning on fitting two wheels onto my badsaw and some sort of third wheel which can be dropped down with a lever to enable me to move it easilly.
I'd love to have a nice big workshop or double garage to work in, but I manage pretty well so I shouldn't grumble, there's plenty of people with no facilities at all.
The sun's out and it's lovely and mild, a bit windy though, I'll drive up to the club and have a bit of a shoot as I havn't been up there for about 3 weeks.
Once everything is all tidy I will start thinking about that 90# Yew longbow.... mmmmm Yew longbow.

Monday, 21 November 2011

Dead wood?

There is much discussion about wood that is dead, standing dead, fallen etc. Some people condemn it outright.
I always say, when in doubt collect it.
As I still had the roof rack on the car I went to see a dead standing Yew near where I live. It wasn't how I remembered it. It was totally unsuitable, so tall that if I did cut it, there was no room for it to fall, it had too many branches and the sapwood was all gone and it was full of splits.
From the base of the tree there were green shoots sprouting, so was it dead or not?
I think a bowyer's recollection of a branch or tree is over optimistic somewhat akin to a fisherman's recollection of the fish that got away!
I had a look round the other trees and spotted a limb sticking out horizontally about 6-7' long broken off at the end with no shoots on it at all. It was about 7' off the ground and I expect kids had tied swings to it. It certainly wasn't a live branch, but the tree itself was certainly still live.
I sawed it down and found the upper surface which I couldn't see had lost all it's sap wood and was pretty manky, however the under surface was fine and the cut face revealed nice thin sapwood and fairly dark heartwood. Definitely worth trimming up and seasoning.
There were plenty of other branches left for the kids to swing on as was evidenced by some rope and old blankets tied to one tree.
I've run it through the bandsaw to cut off the bad half and sealed the ends, I'm pretty sure there is a bow in there.

By the way, the little dolly I made the other day was very handy for moving the long log on my own, I just slipped it under one end and easilly dragged the log from the other end, whereas it had taken two of us to get it on and off the roof rack.

Sunday, 20 November 2011

Yew Log

I harvested a Yew log at the weekend, with some help from my wife.
I'd organised the harvest/purchase with the Forestry Commission. I made initial contact with them by E-mailing a picture of me pointing out the piece of wood I wanted.
They were very helpful and allowed me vehicular access to the woodland, which was handy as it would have been a fair way to drag the wood otherwise. The weather was lovely and my parents came along for the ride too!
You can see the piece I cut is just a side branch, Yew woodland is a protected environment so one wouldn't be allowed to cut a whole tree.
The yew isn't quite as good as I'd remembered, but the heartwood is nice and dark and I think I should get at least one longbow and one shorter primitive out of it, possibly a pair of billets to splice together for a third bow.
I cut the log as long as I could, I shall have to study it carefully before I saw it any further to maximise the use of the wood.
Driving around the woodland elicited some odd looks from the dog walkers, I took the trouble to tell them that I had permission as I didn't want to create any consternation.

Monday, 14 November 2011

Log Dolly

I'm over my cold at last so I've got back to making stuff. I built a two wheeled dolly to transport the Yew log I'm hoping to harvest on Saturday. I just hope I can find it again!
Originally I was going to use the wheels off my roofing ladder, but when I put them on the dolly and put my weight on it the M6 coachbolts holding the wheels bent...
Back to the drawing board. I borrowed the wheels of one of those horrid heavy cheapo sack barrows which we have in the garden shed, they are a bit heavy, but should do the job.
I made the axle from some 1/2" ID steel tube with some stubs of 12mm stainless steel bar epoxied into each end, this makes a lightweight but strong axle. I had the materials lying around from my old electric golf trolley which I made yonks ago. Here's a link to a blog I did about it on an engineering website http://cr4.globalspec.com/blogentry/6416/DIY-Electric-Golf-Trolley

I shall strap the dolly to the log with rubber straps and hopefully it should save my shoulders from having lug a wet Yew log 1/4 of a mile.

Saturday, 12 November 2011

Low Enery Activities

Just beginning to shake off my cold, the irritating cough is easing off so I can get some decent sleep at last.
I've been pottering about refurbishing my target foam in the garage, it was getting rather shot through. I sawed it in half and reversed the pieces so the edges are now in the middle, it should last for a fair while now. I used polyurathane wood glue to put it back together.
I also had a look at my website and found some of the pics had mysteriously vanished, so I tidied that up. I reloaded some of the pics at reduced resolution to save memory usage.
Now I'm feeling perkier I'm hoping to go down South next weekend and harvest a Yew log, gotta get the paperwork from the forestry commission sorted first and make a little 2 wheeled cradle which will strap onto the log to help drag it the 1/4 mile out of the woods.
I'll blog it all up with some nice pics.

Friday, 4 November 2011

Mass Velocity and Energy

I've had a bit of a cold all week, so I thought I'd make do with some gentle experimentation.
The title says it all, how exactly does projectle mass effect speed and energy?
I made a crossbow bolt which I could add weights into by glueing some thinwall steel tube onto a short bolt. A rubber blunt head was then put over the end. I wanted to test for even higher weights and ended up sticking a long M8 coach bolt with several M10 nuts on it into my test bolt. For lower weights I cut down a bolt until it was just about 5" long with no point added. The very low weight bolt actually broke the 200 fps barrier (best shot 202.9 feet per second) .
Pretty obviously the lighter the bolt the faster it goes, what is less obvious is that the maximum energy isn't when the bolt is at it's fastest.
In fact the energy levels off despite the ever increasing weight of the bolt. The real point is that if you want to get maximum range and maximum energy then there is an optimum weight.
For this particular bow you can see it's about 12-15 grams. As the mass increases beyond that the energy doesnt get much higher and the velocity (and thus range) drops off rather a lot.
The text on the graph isn't too clear, so here's a description.
Vertical scale and blue line:- Velocity in m/s
Red line is Bolt Energy (multiplied by 4 to get it to sit nicely on the graph for comparison).
Horizontal scale Bolt mass in grams.
A bit more explanation: (I noticed the 'explain more' box is ticked).
You can only get out of the bow the energy you put into it, or a little less. That accounts for the energy of the bolt not getting any higher once it has levelled off on the graph.
I was slightly surprised that it didn't drop off a bit as bolt mass increased, but there is no real reasn why it should until you make the bolt so heavy that the bow can't push it or friction becomes significant, but presumably that would be at a silly weight, say a couple of pounds.
The energy put in to cock the bow is used up accelerating the bow limbs, the bolt and the string. With the very light bolt more of the energy is staying in the bow limbs and string and less in the bolt. As the bolt gets heavier most of the energy stays with the bolt.
The tips of the bow move faster than the rest of the bow limbs, but even they don't move as fast as the bolt! That's because the string pulls back about 120mm but the bow tips only move back 40mm! That's one of the remarkable things about the simplicity of a bow, a simple piece of string effectively gives you 3:1 leverage.
Anyhow the string and bow tips both return to rest at the same time so the bolt must go 3 times faster than the actual bow tips.
The modern compound bow takes this to extremes by adding extra wheels (like a block and tackle) and cams to make the centre of the string where the arrow is nocked travel much faster than the bow tips. This allows short, stiff, fast limbs to propell an arrow very fast... but at the cost of complexity.