Sunday, 14 January 2018

Shooting Machine

I've modified the shooting machine to be the mk 1.5 . It can now be shot in a more stable manner with a foot on the back end holding down and drawing the bow by pulling on  rope which runs through a pulley.
I took some video, using my new camera with slo-mo capability, of it shooting twister using a regular field shooting arrow and then a flight arrow.
JT took some video of me susing the shooting machine, from which I took a screen grab to show how it works.
I also took some video of my mate JT shooting a warbow at 300, 600 and 1200 frames per second.
Video of the arrows leaving the shooting machine.
Video of Warbow shots

The camera and the shooting machine were a great success. The machine needs some improvement but it certainly proved the concept.
I'll produce a mk 2

Thursday, 11 January 2018

Bow Collected

Martin came to collect the Yew bow and brought Ridgeback, the one I'd made him back in 2012 to check the draw weight.
It was great to see how Ridgeback had matured to a lovely colour, it was interesting to see the bow as I'd made the grip deeper than I'd remembered with quite a high arched D section giving it a slightly Victorian look, but only over about the central 10" or so. It also felt remarkably light in the hand.
Seeing the two bows side by side showed the contrasts and similarities (Ridgeback is the left one in the pic). The top nocks are different but overall they look very much to have the same feel.
He shot a few arrows from the new bow, it looked nicely manageable and was noticably heavier than Ridgeback, which I checked as 55# at 28"
It was good to have a chat and to find that he's hoping to join Cloth of Gold field archery club (which I heartily recommended), so maybe we'll bump into each other up there some time.
He also gave me some beers as an thank you which was much appreciated, especially as I've just finished the Christmas supply!

I'd have taken more pics but the camera (the little Canon SX220) seemed to be playing up... looking through the settings I found the lens retract set to 0 secs, which seems a pretty bonkers concept and is quite likely the problem.
I set it to 1 min and it seems ok now, (hopefully).
Update:-
Just had an E-mail from Martinn to say he weighed the two bows, Ridgeback weighed 580g and Wonky weighed 800g
That's quite a difference so it will be interesting to re-weigh 'em in the summer or in a year.
There is the "Mass Principle" which some people use with bows, which basically says for any particular bow, length,poundage etc there is an optimum weight. I don't use it myself, but the heavier draw weight bow does weigh more, other than that I can't really muster the enthusiasm to delve further into it. I can't really imagine that about five or six pounds of draw weight and half an inch weight should add that much mass. My guess is it's more about the state of the wood.
If you all sit patiently for six months I'll report back. (Sit still hands on laps, no fidgeting!)

Monday, 8 January 2018

Yew Bow Finished

By putting the bow against the other half of the log from which it came, you can see how much bending work I've had to do to get a reasonable shape. The bow still has a lot of character and it's difficult to really see how its flexing. I'll shoot 100 arrows through it and see how it settles. Maybe I'll stiffen the centre with a little heat treating, but that deflex area just above the centre is weird an make it look weak there.
I haven't done the arrow plate yet, but it's a bit chilly for shooting it in or doing the arrow plate at the mo'
It's a tad under weight, 60# at 28" but a little heating after it's shot in might improve that, mind I'm reluctant to risk inducing any sideways bend as I've had to fiddle about with it more than enough.
I'm pleased to say that although it started off looking a bit ugly, it now looks graceful and elegant.
If we get a mild spell I'll get some video of it being shot.
I've had 5 test shots from a decent full draw, it's a tad heavy for me, but it bangs 'em in. Last shot was plumb centre... nice!

Friday, 5 January 2018

Yew Longbow Nearly Finished


I've had to do some more heat tweaking and also had to fill a knot that goes right through the upper limb.
I've done the horn nocks and at last the bow is beginning to look good.
Here's a video of it on the tiller, it still needs a little work, but as it's only at a low brace, hopefully it will make the required draw weight (63# @ 27").
https://youtu.be/LSURouvkDvk
Meanwhile I've been tinkering on the lathe and I ground up a tool to put a 2mm radius onto brass arrow heads. I'd read somewhere that a 2mm radius is supposed to be optimal, but it could be nonsense. Having a shooting machine to do tests may prove it one way or another.