Learned a valuable lesson today

[Badger]

     Man I am pissed but did learn a valuable lesson. Getting ready for the flight shoots next month I selected some of my best bows and decided to drop the weight down to the 50# class from around 57# or so some of them in the low 60's. I had so much work to do I thought I would just use the tillering gizmo which I have been highly recomending lately. The tillering adjustments went very fast and gave me the nice round tiller as ooposed to my usual stiff out of the fades and bending a bit too much just past mid limb. I killed every single bow from very fast to mediocre. I would still recomend the gizmo for a nice durable long lasting bow with decent perfomance but I was shocked at how much I lost getting the whole limb working, I just was not practicing what I always preach because of too much work to do. They all held all their reflex but with the new tiller are handshocky and really lost their edge. Normaly I wouldn't pay too much attention if it were only one bow but I am talking at least 8 that I have tested so far.  The best bows went from around 180 fps with 10 grains to around 167 which is not bad but won't compete at a flight shoot.

[missilemaster]

Too bad, I feel your pain! But you know what you  need to do now? Go build your self 8 new bows with better speed than the last ones!!

                                                  Cody

[Del the cat]

Oh dear, I bet that little voice in your head was trying to tell you it was a bad idea to mess with more than one bow at a time.
We've all done it... ignored that little niggling doubt that's yelling at us to stop .
Interesting that your stiff middle style gives you better speed, I tend to get confused, as for ebery article I see saying whip tillered is fastest there's one saying long stiff outer limbs with the inner third working is fasted. S'pose that's why I stick to my circular tiller, mind I don't flight shoot, but my bows seem to compare favourably with the run of the mill.
Keep buggering on as Winston Churchill used to say!
Damn, you've got me thinking now... bad mistake.
Presumably with the whole limb now working, you should be able to draw 'em further. Now could you draw one back to it's original draw weight, and if so what speed would it get???
Maybe there's one you would risk trying it with. That's the problem with this game, everything you chnge effects everything else.
Presumably you were expecting a slight loss in speed as you reduced the weight? In flight shooting presumably you have to go from a measured draw length (measured arrow?) what speed would you have got with the old tiller shape if you had just drawn short to the 50#...
Sorry for the dumb Qs, I said thinking always get me in trouble.
Del

[Badger]

     Del, they are very decent shooters still, mostly below the 170 mark though which just won't compete. Normaly I am stiff out of the fades and gradualy increase the bend until aboyt 12" from the tips where I start to stiffen them up again.
    Per your question, I went back and checked my hunting bow and it is pulling 50#@25" and hitting 173 with a 500 grain arrow. I will go a head and stretch it out to 28" using the same tiller shape it has now and hopefully hit 180. I am pretty sure 175 will get me by ok.

[PEARL DRUMS]

I could take nearly all my finished bows and get marks on them the first 12-14" of limb with a gizmo if I used one. I use my eyes rather. Its a great tool to get your eyes trained. Sorry for your loss' Steve.

 

[LivingElemental]

That's really depressing. My heart breaks for every piece of wood I ruin, so I get how bad that must be. Good luck at the shoot if you're still going.

[Badger]

  In some ways I am glad it happened, I never really realized how dramatic the difdference is. I never used a circular tiller before. Now all these bows are testing at about the same thing most bows I test for other people test at, makes sense because they have the same tiller shape. I have some old stuff I can tune up, my budget for staves is about overdrawn.

[hunterbob]

Looks like it is time to make some more . You know the first osage bow I made about six months ago was under the watch of blackhawk's eye.Then the next eight was done with the gizmo on my own and none was as fast as the one I made at Blackhawks.Then the last two I made in the the last week was done with just eyeing them up and they are fast and the tiller looks alot better . And they didnt take on hardly any set. I think I will stick to using my eye.

[George Tsoukalas]

I never had much luck starting heavy and going light. Shifts the neutral plane resulting in more set, at least for me. Jawge.

[Badger]

   I didn't use the gizm to make them, I thought I might just save some time dropping the weight. I have two of them back to speed allready. Cut them down a tad and changed the profile. Something else I notice is that straight reflex is not nearly as good as a slight reflex deflexprofile when braced. That makes about 6 fps difference on the average. I use a form on my last batch when heating instead of my usual just bend them over a log and it made a pretty big difference. Last month or so I treated my bows like a production line and they came out like production line quality. If I were going to start selling bows though I would make them this smae way. Give up a little in speed but I think more durable.

[wvarcher]

I bet you still end up with a couple more flight records this year Steve.

[Del the cat]

Interesting discussion as we don't often talk about re-tillering bows.
Are these self bows or laminated we're talking about here?
Del
(PS. How many of us want to run a mile when we hear that phrase "we don't often talk"... you just know there's trouble and earache coming )

[mikekeswick]

I'm interested why you changed the tiller when dropping the weight. What sort of width taper did they have before re-working?
I have made quite a few ELB's and to begin with I tillered them to be circular with a straight taper from handle to tips. These bows were fast but also a little shocky. Now i've moved to a more elliptical tiller  and use a longer parrallel width section in the center of the bow which then tapers to 3/4 wide about 12 inch from the tips. I've found the elliptical tillered bows to be much less shocky and also faster. Does this agree with what you've found with elbs/any bow??

[Badger]

  Mike definitely more elyptical is better. I have no idea why I did it the way I did it except I was thinking the small weight change would not have such a big effect. Durring that same period I built two hickory backed reflexed bows, same problem with lower performance.

[Badger]

  Well, feeling a lot better. Went through my stock and retuned some older bows and re did a couple of the ones I screwed up and feel like I am back in business. The low elevation yew bow I posted a while back seems like about the top contender right now, after inducing some extra curves and reflex.