Handling of reflex when tillering

[Gordon]

Put the weight on and see how far it goes down. I'm surmising from your description that the limbs will be about straight or slightly deflexed. Then put a stop a couple of inches below the weight and see what happens.

[George Tsoukalas]

You have 3 inches of reflex. I would long string tiller out to 13 inches ( I usually go to 10 inches) of string movement looking to get 5# over  target weight. Good tiller, of course. Then I would string it up with the short string. Remember that reflexed staves show high early draw weight when strung and tillered. If at any time you feel the stave is getting to thin then begin to remove wood from the width. See Bow Making Directions on my site. Jawge
http://mysite.verizon.net/georgeandjoni/archer.html

[BigWapiti]

Well, I had time to give this a try today - put a strap on each limb about 18" up from the handle and hung 50# from it for 3 hours.  No change.  Then hung it again for another 3 hours.  No change.

Hanging 50# on it doesn't seem to bend it into position at all.  Strong wood!

First pic is the bow just sitting in the tree.
Second pic is my rig for hanging the 50# weight (were you thinking something different?)


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[Rich Saffold]

Mike, Your dog just told me he thinks you got 6-7" of reflex.    That is a bit of a challenge as getting this to come around might make it lighter than you want. It would have an interesting braced profile. I'm sure Gordon will tell you which method will reduce the reflex best.

Rich-

[BigWapiti]

yeah, no kidding - I'm thinking of turning this one around and just stringing it up backward.  It seems to want to bend that way no matter what I try.

I think I need to try strapping these to a board after splitting the log w/ the bandsaw.  They hold a lot of reflex.

[Gordon]

Try hanging the weight from the tips.  If that doesn't help then just start taking off only a little wood at a time (with a scraper) and exercise the h*ll out of it between each session.

These highly tensioned vine maple staves have a lot of spirit - you gotta break 'em before they start coming around...

[BigWapiti]

Thanks Gordon - I'll put on the spurs and give it a bunch of 8 second rides to try to tame the beast (sorry, no coffee yet this morning -heh)

Having the weight on the tips had it trying to 'break' at mid limb instead of across the board -- I suppose that means I have a nasty hinge that'll show its face once I do get some of that reflex out of it. - but I do have another idea, using your 'break it slowly' suggestion.

Actually, another question - any suggestion on how to prevent so much reflex on VM staves?  Have you had much luck strapping them down after roughing them out?  Seems that no matter what, that reflex just starts up as soon as its removed from the jig.  Thinking 'out loud' here, maybe I need to have a little more patience and keep them strapped longer.

Whats life without a little challenge.

-m

[Keenan]

 Big Wapiti,  looks like youv'e been given some sound advice. Another alernative might be to consider what I did with the syringa gull wing bow. It had almost the exact same start. I just heat deflexed the limbs right at the fades. Here are a few pics.  Keenan

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[Gordon]

any suggestion on how to prevent so much reflex on VM staves

Avoid harvesting vine maple that is leaning heavily without support. If you tie it down to prevent it from reflexing, it will just curl up when you untie it.

[BigWapiti]

Thanks Gordon - you caught me.  The VMs I've been harvesting were of the 'bush' type and having a lot of lean to them, there must be quite an amount of tension in the wood.  Especially to hold that heavy trunk up, particularly under snows.   The point you make is a good one - of the two VM bows that I've completed successfully, those were cut from more upright standing trees.  Thanks for that - good advice.

Keenan, thanks too for the advice - I'm going to give it another try - but I've not had much luck steaming or heating reflex out of vine maple.  Its worth another American try though; not like its going to hurt anything, except my pride. My neck and shoulders are already sore from making shavings.

Thanks again guys.

[Gordon]

One more thing. Be very mindful of limb thickness while you are removing wood. That's because it is hard to detect hinges in a heavily reflexed stave until it is too late.

Good luck!

[brian melton]

          Keenan has it right, work on the fades...

[BigWapiti]

Keenan,

You say you heat deflexed it.  I'm going to build a jig as you show and give that a try.  I've always just put the handle in a vice and hung a weight off the limb, using heat until the weight hit a stop.  But maybe forcing it via clamps is a better way to go.

Do you heat it up first, then work quickly to get it into the jig?  Or are you applying heat while its in the jig?

Last question is - when I use my heat/vice/weight method - I don't use weights that are heavier than my desired draw.  Thinking that more weight is like over drawing when its on the tree.   When clamping, how do you know if you're putting too much stress (compression) on the wood?

Come to think of it, I'm hanging 50# off my limb, because my bow is to be 50# -- BUT, that still means my limb is getting 2x the weight it would get a desired draw wt.

Am I completely overthinking this???

But if I am, why is it so important then, not to draw over weight while tillering?

Oooh, soo much thinking for a monday. 

[Gordon]

Mike,

If you are going to try to bend out the reflex at the fades I would steam the area first and then clamp it to a form. I've not had much success using dry heat to bend vine maple wood a good deal - it tends to crack. That said, I expect that the reflex will reappear within a week. At least that has been my experience. But give it a go - you've got nothing to lose...