Monkey Bow New Levers

I did new levers, got the geometry just pretty good , although the right lever lifts first, you can see the string is just about to lift off at 50#. There is plenty of wood on the levers to allow some adjustment.
I had thought I should bind the splices

with linen thread soaked in epoxy, but this is just an experiment and I couldn't be bothered. Watch the video and you'll see why Monkey is so shocked!

I think what happened is:- As the string lifts off the join the lever comes into play and exerts a large force on the splice which splits it open like a wedge. A binding of thread may well have stopped it happening. Hmmm, I'll know next time. Still it's been an interesting geometry lesson.
Looking closely at the video in slo mo, it also looks as if the bow flips, that is to say the levers aren't correctly aligned and it pulls the tip towards the camera, hence the way it spins towards the camera... I still haven't found the missing end! there is maybe enough limb left to make a little shortie bow, it will be nice if I can keep the Monkey face.
And there's two free bowmaking lessons.
1. Don't be greedy going for too much draw weight.
2. Don't think "I can't be bothered " and spoil the ship for a ha'poth of tar!
Update:-
Do not despair dear reader, Monkey Bow will live on in the hearts of men! (whooop whooop) I've managed to reshape the split upper limb and done the lower to match. I will splice on a V short extension to each limb (adding say 1-2") with the point of the V being the limb tip this time, this will be reinforced on the back with an overlay which will be part of the join and the nock. I'll aim for a short draw say 24" at about 40# or what ever I can get out of it, it will just be a novelty bow and of course a learning exercise.

Monkey Bow on the Tiller

I've got the Monkey bow at a 4" brace (note the limbs are naturally deflexed to start with). Here's a frame grab from some video which shows some interesting points.
The digital scale was great from me to see while pulling the bow back (it was reading 50#) but it's not legible on video!
The levers  aren't coming in to play yet. E.G The string is still resting on the tips of the bow and has not lifted off.

If we assume I wanted the string to be just lifting off, I can work out where I'd need a string bridge at some point on the levers to make this happen. (See diagram) I can make some adjustable string bridges to try various configurations, but first I need to get it to full brace as that will effect the geometry.

Improving the tiller (although it's surprisingly good already) will reduce the draw weight a tad and also let me get the brace up.
By the time I've done that the levers will be coming over a bit more and the string bridges won't need to be as large as shown in the diagram.


Here are some pics of a decent Siyahs cut from Ash with a natural curve to the grain and splice in with a good length of joint. The joint is then bound with linen thread soaked in epoxy. This bow was actually faced back and belly with a fibreglass lamination.
I'll post a pic of the much shorter V splice on the Monkey bow in my next entry.

If I decide on different lever geometry, I can always find a bit of curved Ash and re do the levers with a longer stronger joint (assuming it doesn't explode first).

Update:-
I've done a bit more and got the brace height up a bit, I thinks the limbs are pretty close to how I want them, but I thnk the levers are just at too extreme an angle.
I'll have to see if I can find some Ash with a slight curve in the grain and re-do the levers. At least I just did this quickly, another triumph for my WAQAP quality philosophy! (That's Wrong AS Quick As Possible). I could have wasted ages doing drawings models, geometry and arithmetic only to find it needed re-doing anyway, I've a sneaking suspicion that string bridges are actually a fine tuning mechanism.
You can see that the levers on the Asiatic recurve are at too shallow and angle, somewhere in between is the Goldilocks zone where they are just right.

Messing with the Monkey Bow

I've been pottering about doing a bit of this and that. I can't concentrate for too long, because of my cold, so I picked up the Monkey bow, a short deflexed bit of Elder which I'd roughed out ages ago. I was planning to add levers (Siyahs) onto to the ends. I'd been toying with making a scale model and trying to work out fancy angles and such like so the string would lift off a couple of string bridges progressively as it approached full draw. I soon realised I don't have the necessary physics or maths to work it out and to make a model would be as much work as doing the real thing.
I'll just wing it, I've some experience having done an Asiatic recurve from f/glass (spits on floor) laminations and also a Hazel recurve with fairly extreme flipped tips.
Anyhow, if non of that makes sense, just bear with me and eventually you'll see what I'm attempting. Dunno if it will work, but it's giving me something to play with.

The funny knots above the grip (left pic) give it the name Monkey Bow...( whooop whoop Ah ah ah).
S'pose I should say what I'm aiming for... I have no idea really, so lets say 40 at 26", maybe 28"?. The glue joints don't have much surface area so it won't take much more than that.
The purpose of the exercise is twofold. To have a play with Elder and to have a look at some lever geometry. If it works at all it's a bonus.
Glue should be dry tomorrow, so I can mess about with it, dunno if I'll feel up to shooting, just planing those two levers had me puffing and blowing like an old man... mind I s'pose by the standards of my youth I am an old man.
Nah 60 is the new 40 :-)

Touch of Man Flu'

I've been taking it easy, finishing the bracket for my new digital scale. I couldn't be bothered with endless filing and smoothing with emery so I took it to Mick the Blacksmith's workshop.
It took an age to find his place as although I'd been there once before I wasn't driving that time. I tried my new satnav, which drove me right past the entrance, and a mile up the road to a caravan site!...  I got there in the end. Mind at one point I pulled into a lay-by to take a rescue call from Mick on my mobile... some bloke in a van tooted me and pulled up alongside shouting abuse... would he rather I'd just stopped on the road? Or maybe driven whilst taking the call, which is what most van drivers would do? I click down the 'lock' button for the car doors and waved him off... I'm too old for silly road side altercations and arguments. Yeah, ok, I had pulled in a bit sharpish, but if it actually inconvenienced him, he must have been too close, or maybe he was busy on his phone?


I used Mick's bead blaster on my mild steel bracket which smoothed it off nicely. Then we got it red hot and quenched it in oil to blacken it, nice looking job.
While I was there we had a good chat and he showed me his rolling mill which he'd made, for rolling out red hot pattern welded steel billets into blanks for swords and knives etc. It's one of those machines that you need to see in use to appreciate how it works. We joked that we could post a good YouTube spoof of using it to create wooden laminations by rolling out a billet of wood.

After a couple of hours, the man flu' was kicking in so I drove home for some nosh and a 10 minute catnap that lasted 2 hours.


Mick very generously gave me two billets of his pattern welded steel blade blanks to take with me on my forthcoming trip as gift/trade items for the natives ;-)
The numbers on the billets indicate the number of steel layers. Google Mick Maxen to see more of his work.

Just tried the new scale on my 50# side nocked  ELB it read 47.8 lb which is good, it was good and legible, it also clipped nice and securely onto the bow string.

Ashbow Re-Try

I went up the club with 3 bows and came back with none!
The Ash bow (nicknamed ASBO) was tried out again and seemed to chuck arrows a good bit further than before, mind there was a bit of a tail wind. I took some video and grabbed a still, you can see the difference in tiller Dave is wearing red in todays pic.
There is another difference, the string has 2 fewer strands and is braced slightly lower, both of which will help cast.
That bow has found a happy home as a train up bow for the 100# Elm.
the other two bows were a tired old Hickory one which didn't belong to me but had somehow found a temporary home in my garage, and finally the Hickory Backed Yew which is being lent out for an ILAA shoot at the picturesque Hever Castle, it maybe slightly low in weight but as a 'shoot it all day bow' it could be just the job. It's not finished, but if it does the job I can put a grip and arrow plate on it and finish it as required.
I need to give the garage a good sort out and make an hook for my new scale.
With the nice weather there's gardening and DIY too, mind having put up 4 roller blinds along our large South facing patio doors, I've earned a few Brownie points.

I often see people stating that the front profile of a bow dictates the shape of it's tiller. Personally I think this is total tosh as the stiffness of the bow is directly proportional to it's width, but it is proportional to the cube of the thickness. Thus thickness is vastly more relevant than width.
OK the front view (profile) of the bow will dictate the tiller curve IF the bow is constant thickness. An example is a Pyramid style cut from a board of even thickness. (e.g a bow tapering in width from say 2" to 1/4" will have a nice curved arc of a circle tiller shape).
Anyhow, I was banging on about this on Primitive Archer, saying you could make a bow which tapered the 'wrong way' width wise and still tiller it to an arc of a circle. Someone challenged me to do it (in a good natured way) so I made a miniature to illustrate my view.
I dubbed it the Dimaryp Bow.

E-Bay Find

For ages I've been whingeing on about the difficulty of reading draw weights accurately.
Now I'm under no illusion at digital is necessarily more accurate, but when I was mooching around on E-bay  one lunchtime (as you do)  I spotted some 50 kg digital hanging scales luggage scales at a silly low price. I got 'em for £5.30 including postage! Can't lose at that price, they arrived this morning and look very nice, good back lit display (the back light has switched off in the pic)
It can be set to read in pounds and it's even got a smiley face, what more can I want?
I'll have to make/modify the handle to hook onto the bow string, but one advantage will be the lack of mechanical backlash and absence of elongation which you get in a spring type scale. It will be handy to see how it agrees with my other scale.
Only going up to 110# will limit it a bit for warbows, but it's great for the general draw weights and will certainly cover anything I can draw.
If you look for one, watch out as some only go up to 40kg.

Good Result (I hope!)

I've got home from work, strung the bow and put it up on the tiller. The heat treatment of the upper limb has had a day to settle.
It read 80# at 32", a nice improvement and just about what I was aiming for.
Let hope it stays sound. I'll just give it a few coats of Danish oil and buff up the horn nocks.
It could actually be quicker now. If it's the same draw weight and draw length and it's now 2" shorter and has lost about 90grains of tip mass, it may well be a tad quicker.