How much reflex is too much?

[Pat B]

Since Guy suggested starting a separate thread for this subject I thought I's start one.
  IMO you can add too much reflex to a stave. As a matter of fact I reduce the reflex if it is over 3" to 4" of natural reflex and generally won't add more reflex than 3" to 4" because I think by doing so you are over stressing the stave which can easily increase set.
 For sinew backed bows I will add a little more tied up(strung backwards) reflex until the sinew cures but after my bows are shot in there really isn't that much reflex left.

[Ink]

HAHAHA you beat me to it Pat, i was even gonna name it that! I' gonna be watching this thread closely

[PEARL DRUMS]

I add 3-4" on every bow I build, almost. Ive learned to adjust that for different woods, different lengths and different styles. That could be a chapter in a book all by itself. I used to add excessive reflex, was told not to by the guys, and learned in my own time that it doesn't work without sinew or a glued hard backing. I would rather start with 3" of reflex and end up with 1.5" than to start with 8" and end up with 3". Taxed wood is taxed wood and held reflex alone doesn't mean much.

[koan]

I made a form just like Gary Davis .. where reflex increases toward the tips.. It greatly reduced the amount of set i get, and like Pat said, if a stave has alot of natural reflex I take some out...least thats what works for me.... Brian

[SLIMBOB]

Been reading the various posts on this issue over the last few days.  A good question Pat.  I think I know the answer that I feel is right, but I have no hard evidence to back it up.  Like PD above, 3-4 inches, settling at 1-2 inches depending on the length of the bow, and a few other variables.  When I first began, I made a 58-59" Osage bow from a straight stave and I flipped the tips which gave it an inch or so of reflex.  Liked it so much that I then added some set back in the handle, about an inch if I recall and that gave it 2+ inches of reflex.  Liked it so much that I heated in another 2-3 inches along both limbs.  A real beauty! 5 inches or better of reflex.  It looked and felt amazing, like a high horned Brahma.  It settled in at about 1/2 inch of string follow, most of that from mid limb out.  Too much of a good thing.  Better to have induced 2 inches and have it settle dead flat or better (I think), which is more of what I would do now.  I'm interested to see what everyone else's take is.

[PatM]

Steve(Badger) has done a lot of testing on this subject. I believe he mentions anything over 2 inches being of greatly diminished benefit.
 It has to do with how the wood is coping with the increased strain.
 

[PEARL DRUMS]

It seems bow length would play a part Patm. It does for me. I tend to add a bit more to longer bows that I know wont lose it so readily.

[Matthias Wiltschko]

The more reflex, the wider the limbs have to be to stabilize the bow. This also means more mass that has to be accelerated.
I am struggeling on my own if to reflex a bow 2" and get zero stringfollow or adding 4" and get 2" reflex plus wider hand heavier limbs.
I would take 2" for a longbow and 4" for a flatbow with wide limbs.
Matthias

[Onebowonder]

Wouldn't the issue here vary greatly depending on wood species for self bows and materials characteristics of belly and back pairs for backed bows?

For example, consider the difference between an Osage self bow, (which is very strong in both tension and compression and well ballanced between the two), and an ERC self bow, (which famously poor in tension, but pretty good in compression and poorly balanced between the two).  The Osage self bow could almost certainly handle more reflex that the ERC.

Or for backed bow pairs, wouldn't a boo backed Ipe bellied bow be different than one with a Maple back and an ERC belly in the degree of reflex they can readily support?

OneBow

[PEARL DRUMS]

The amount of added reflex changes little Onebow. The difference in the woods would require more length or width to hold the same amount of reflex in the end.

[huisme]

With my black locust anything more than four inches on a 60-65" bow looks like trouble for the belly. After that I feel save adding one inch of reflex per five inches of bow length, but I'm sure that's playing safe.

[Bryce]

so wait...there's such thing as too much?
lol

[Badger]

     My take on it is that the more elastic a piece of wood is the more you can reflex it and get benefits, most woods are very similar in elasticity. I find with osage, yew, elm, for the style of bow I build which is a 66" long bow most of the time I like about 2" or 3" tops.  Personnal shooting bows 1" is plenty. The bow I did so well at the flight shoots with this year had 3 1/2" but was a little bit of a freak because it never lost any durring the build. Yew and osage will sometimes surprise me with how much they will hold but I don't like to push it because if I am wrong I end up with a broken or at least broken down bow. I have also found that if I use too much reflex I need to make the bow too wide and thin which seems to cut back on the efficiency even though the force draw curve will be excellent.

[Onebowonder]

The amount of added reflex changes little Onebow. The difference in the woods would require more length or width to hold the same amount of reflex in the end.

...which is to say that too much reflex for a given set of dimensions VARIES significantly by wood species in self bows and Belly to Backing pairs in backed bows.  An Osage bow of X inches in length and Y inches in width can accomodate N inches of reflex before it is too much, whereas an ERC bow of the same dimensions can only accomodate N minus something inches of reflex before risking failure.  Of corse it all changes if you add more material to share the work...

OneBow

[SLIMBOB]

I think PD's point is that adding more wood is a given for "weaker" woods.