Author Topic: Tillering warbow with reflex  (Read 18871 times)

0 Members and 1 Guest are viewing this topic.

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: Tillering warbow with reflex
« Reply #30 on: May 28, 2013, 03:49:13 am »
Shift the string across at the nocks , maybe clamp the grip or put a thin wedge under it. You've got to for ce it to do what you want.
Lots of small corrections can make all the difference and once it's back to about brace it will be easier to hold it in line.
Leave the tips full width and stick a scrap of wood on the back at eah tip to cut a groove in for a nock. This maximises your lateral string adjustment.
Persevere now and it will be ok later on.
Del
Health warning, these posts may contain traces of nut.

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #31 on: May 28, 2013, 08:03:14 am »
The tips are 20mm wide and even with the string loops on opposite edges of the tips the centre still falls off the side of the handle.   It gets worse at brace as well.  I wouldn't mind so much but it's now so offset that it's flipping constantly on the tiller.

I might have to do what you said and clamp it flat on the tiller, but that will require building a new tiller setup as I can't do that on my current one.  Laminate bows are looking so tempting right now  >:D

Offline toomanyknots

  • Member
  • Posts: 3,132
Re: Tillering warbow with reflex
« Reply #32 on: May 28, 2013, 11:18:53 am »
I definitely agree about the whole left limb needing to work a bit more, so I'll take the whole limb down a fraction.  I'm wary about playing with the middle too much yet, as it's not even brace height yet, and I don't want the middle working too early if that makes sense? 

The tillering string is just an extra long bowstring, from about a million strands of B50.  I'll shorten it up once I've got the left limb a bit weaker and see where I am!

Good point about the middle, you always want to get that really bending last. Or at least I do. I kinda meant the "fade", but you have a good point too. I usually tiller the bow from the tips outward kinda, but mostly just look for areas that are bending too much or too little. B50 is stretchy, and imo sucks as a bowstring and definitely a tillering string, when the weight is higher. What works great is some 550 paracord, as there is like no stretch and you can just tie it in a normal knot without worrying about it breaking. I by mine at lowes for 8 bucks for about 50 feet or so. Fast flight would make a better tiller string as well. And I am thinking like abd, the pop was probably just the string popping out (did the string come off at the same time of the pop?). Well it may of just popped out a little bit and make a sound without coming fully out, I have had it made noises before. I think the best thing to do in this situation, if you can't clamp it down, is to get a mirror and lay it horizontally on the floor, and tiller the bow by stepping on the string and pulling up while looking at the mirror. You have to be careful not to hurt your back while tillering heavy bows like this, but other than that, I think it works great as you can hold the bow firmly in your hands and keep it from flipping over. When you get it up to a 6" brace (if you floor tiller it far enough and good enough you can go right from floor tillering to a 6" brace, but it takes a bit of practice and sometimes you might whip the tips if you don't get the full limb bending.)
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: Tillering warbow with reflex
« Reply #33 on: May 28, 2013, 05:19:58 pm »
The tips are 20mm wide and even with the string loops on opposite edges of the tips the centre still falls off the side of the handle.... 
That doesn't make sense to me...
If it's flipping one way, then the string needs pushing to the other side at both tips.
E.G. Facing the bow, with it's back uppermost, pulling down on the string (say there's a wall bahind the bow). If the tips are coming towards you instead of straight down. Then the string needs to be pusshed to the back edge of the nock on both tips, towards the wall. This will move the string line to the wall side of centre encouraging the tips to move towards the wall rather than towards you.
If you've moved the loops to opposite edges, then the string line at the middle of the bow it's the same as if the loops were both dead centre as the string is running diagonally across (like a bow with side nocks).
(or maybe there's just a breakdown of communication here...)
Del
Health warning, these posts may contain traces of nut.

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #34 on: May 30, 2013, 12:14:41 pm »
I think I must have missed something fundamental when learning how to make a bow. 

This extra wide piece of seasoned ash, which started with 3 inches of reflex now has 3 inches of string follow, which equates to it having taken 6 inches of set.  It's not been pulled anywhere near the intended draw-weight, and has only come back to about 18 inches so far. 

To make matters more annoying, the lateral bend gets worse each time the bow is braced (although I've never even got it to a brace of more than 2 inches yet) and is now pretty much unworkable as even with the string loops as far across as possible on both sides the string is still nowhere near the handle anymore.  It doesn't make any sense to me!  I've gone slowly, and left plenty of room for mistakes.  The tillering was slow and gentle and like I said, I never went beyond the intended draw weight.  I haven't even reached it yet!

Offline Yeomanbowman

  • Member
  • Posts: 283
    • warbowwales
Re: Tillering warbow with reflex
« Reply #35 on: May 30, 2013, 12:29:14 pm »
A few thinks to look at.
1.  Did you taper the width from the handle section?  If so it can affect stability.  Better to start these tapers a bit further down the limb or go for 2 tapers.  With the nocks 20mm wide it doesn't sound like the limbs are too narrow.
2.  It sounds like your ash is too damp.  Keep it inside between the times you are working on it.  Some bowyers don't even let ash bows rehydrate after heat treatment.
3. Was your bow too rounded in the belly as well?
4. You may be able to rescue matters by heating the bow and bending against the direction of the cast.

Jeremy

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #36 on: May 30, 2013, 12:49:23 pm »
Hi Jeremy!

1.  I did sort of follow the MR bow tapers, in that the centre 20 inches or so is pretty much parallel, tapering once towards the tips, and the goal was to taper again the last few inches to the 15mm nocks once the bow was 90% tillered
2.  The ash is a good few years old, and always kept inside.  Not near heat especially, but somewhere warm and dry.  I would love to blame it on the wood instead of my poor skills, but I think in this case it's all me!
3.  The bow was almost square, instead of the traditional D section.  I know that ash is tension strong, so the belly needs to be far flatter than a traditional yew longbow in order to avoid set
4.  I'm gonna have to heat this, but I was really hoping not to!  On the Warbow Wales website is a record breaking ash warbow with very similar dimensions to mine that hasn't been heat treated or reflexed at all.  I end up having to heat treat every bow I make to rescue or avoid string follow and each time I start a new one I aim to avoid needing to do it. 

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #37 on: May 30, 2013, 12:50:10 pm »
This is the bow I was following as inspiration

http://warbowwales.com/#/welsh-ash-record-bow/4562210258

Offline adb

  • Member
  • Posts: 5,339
Re: Tillering warbow with reflex
« Reply #38 on: May 30, 2013, 04:23:02 pm »
Did you notice at the bottom of the description? No reflex or heat treatment.

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #39 on: May 30, 2013, 07:11:35 pm »
Yep, that's why I don't want to resort to using heat.  It's clearly possible to make a heavy ash warbow without it!  I assume they mean there was no added reflex.

I wonder if I'm trying to run before I can walk.  I've only made a few bows.  Would you say a heavy bow is harder to make than lighter bows?  Perhaps I should stick to bows around 50# until I've got the basics down?

Offline adb

  • Member
  • Posts: 5,339
Re: Tillering warbow with reflex
« Reply #40 on: May 30, 2013, 11:52:19 pm »
Yes, I would definitely say making heavy weight bows is harder. Is for me, anyway.

Offline toomanyknots

  • Member
  • Posts: 3,132
Re: Tillering warbow with reflex
« Reply #41 on: May 31, 2013, 09:54:10 pm »
Yes, I would definitely say making heavy weight bows is harder. Is for me, anyway.

Shoot, for me it's the opposite. For me tillering lighter shorter bows takes more skill than warbows, just because removing less wood makes for more of a difference in tiller. And I think it is easier to get chrysals or a bow breaking hinge in a shorter bow. I only get chrysals in warbows if I use a weak wood, for the most part the bows are so long is it hard to really stress em too much, despite the high weight. This is how I feel anyhow. Now it sure is physically a lot harder for me,... I need the exercise though!  ;D
« Last Edit: May 31, 2013, 10:00:38 pm by toomanyknots »
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline toomanyknots

  • Member
  • Posts: 3,132
Re: Tillering warbow with reflex
« Reply #42 on: May 31, 2013, 09:57:14 pm »
This is the bow I was following as inspiration

http://warbowwales.com/#/welsh-ash-record-bow/4562210258

And that fellow sure is drawing that bow funky like. He is drawing it unevenly, mostly the bottom limb, you can see it in the arrow and the bottom limb bending more.

Edit: And with a hemp string too, cool! Don't see alot of those, must be good hemp not the stuff around here.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline WillS

  • Member
  • Posts: 1,905
Re: Tillering warbow with reflex
« Reply #43 on: June 01, 2013, 04:55:05 am »
I think I fell straight into the trap Del was talking about, by making the reflexed limb weaker to match the other.  It certainly wasn't deliberate, and I was trying my hardest not to do it, but when looking at it on the tiller I just couldn't trick my eyes into leaving that limb alone before it was really working.  If I'm lucky, and with a LOT of heat treating, this bow that was designed to be 100# will finish at about 45# which is diabolical.  It will also be massively overbuilt for that draw weight, and having been pulled to around 80# during tillering is of course hugely over stressed.

I always try and take away lessons from each failure to avoid it happening the next time, but apart from the above, I really don't know what went wrong here.  I'm still in the dark as to why it suddenly started bending sideways, and really surprised at how much weaker the limb that originally was reflexed the most now is. 

I like to think part of it is down to using an adapted Mary Rose design on a bow wood not suitable.  I know that ash works well with some heat treating, and especially well with a trapped back.  But that bow on the Warbow Wales site has completely thrown me, because it breaks all of those rules and still comes out at an unbelievable draw weight.

Offline Yeomanbowman

  • Member
  • Posts: 283
    • warbowwales
Re: Tillering warbow with reflex
« Reply #44 on: June 02, 2013, 06:15:49 pm »
Another factor to think about is density.  Ash can range from .6 to .8+ SG and it makes a large difference to the draw weight for the dimensions.  There's loads of ash about (at present:-/) so have another go and make some shavings! 
Why not give this bow away to a young archer and build on what you have taken from this bow in mark II, and after all, it was a bow and not a load of splinters!
Good luck.