Author Topic: Using reflex (Read 10352 times)

Badger · « **on:** May 23, 2007, 05:05:15 pm »

I have seen quite a few posts on bows talikg about reflex and just thought I would offer my take on reflex.
I feel that if you want a bow to end up with 1" reflex you should start with no mare than 2" or if you want it dead even start with no more than 1'. Thi spast year I have started testing my bows far earlier in the process than when they are finished usually somewhere around 22" I begain checking the performance. It is amazing how much performanc is affected at the slightest sign of the bow taking set from it's original starting profile, even before set becomes actually visible. The last year I have spent a lot of time trying to interpet this into something worth talking about and trying to look at it from different angles. The more I get into this the more significant it has actually become. I am seeing bows that at 24" of draw are basicaly peeked out, shooting at very high levels of performance even at that short draw, and start going downhill from that point on even though they look great and still end up good shooters. As an experiment I started going wider than I normally do to reduce the stresses and extend the draw a little more before the breakdown actually started to occur. I figured this would cause me to readjust my mass principle a little. To my pleaseant surprise the wider bows actually started comming out lighter than the narrow bows and much faster. Only thing I can attribute that to is no dead, crushed wood cells on the wider bows and all the wood on the bow is contributing to storing energy. Nothing new here, the guys from 50 years ago were preaching this same thing. Steve

koan · « **Reply #1 on:** May 23, 2007, 07:05:08 pm »

Makes alot of sense to me.....Steve, your one of those rare individuals that can do and teach....Thanks

Brian

Justin Snyder · « **Reply #2 on:** May 23, 2007, 07:42:14 pm »

Thanks Steve, it is sure nice to have someone who is studying the bows as they build them. This keeps us all on the road to building better bows. Your sharing it also helps those of us with less experience build a good bow when we could be trying to learn everything the hard way Thanks again, Justin

Jbell · « **Reply #3 on:** May 23, 2007, 11:49:26 pm »

Great info Steve, nice having guys like you to teach all of us a thing or two. Thanks for sharing your thoughts and theories.

Do you have any thoughts on why the wider bows are turning out lighter? For some reason in my mind they would be about the same weight, as a narrow bow will have a thicker belly and a wide bow will have a thinner belly for the same draw weight. Sorry If i am not making any sense.

Jbell · « **Reply #4 on:** May 23, 2007, 11:59:01 pm »

OOOh Yeaah, now I get It duh! The wider bows are taking less set therfore need less wood for the same draw weight as the narrower bow with more set which needs a little more wood for the same draw weight. Or maybe I don't get It, thanks for making me think though.

Pappy · « **Reply #5 on:** May 25, 2007, 07:31:11 am »

I have come to believe that Badger is right on this one,[as usually].We built some forms a while
back that put over 6 in. of backset in the stave's before tillering trying to get them to stand at least straight when finished and sometimes got a inch or 2 backset to stay in them but as my tillering has improved I find they do better with 2/3 in. of backset to start with and if you do it right it will hold at least most of it.Don't break as many bows now and they seem to shoot better.They hold there tiller better after they are finished and usually never have a problem
with them changing after being shot a bunch.I think when you put a lot of backset in it ,it dose something to the wood and makes it hard for it to settle in.No hard data on this just some thoughts.

Pappy

DCM · « **Reply #6 on:** May 25, 2007, 09:49:12 am »

I see net reflex as being the same as both higher brace height and draw lenght. It's simply more deflection. So 1" of reflex is like a bow braced 7" and drawn 29". I think if you design for it, extra wood, it can be down without penalty. But then you have a bow that's generally loud and sensitive to poor form (lots of push left at the end of the power stroke). In combination with some deflex you can get away with more. In this scenario you still have to design for extra load but mitigate the manners. Like most things in life, it's the Goldilocks thing - just right is just right.

I don't know who ya'll can tiller out bows and only give 1". It's the rare project that I can get done and give less than 1 1/2", frequently 2". And based on what I've heard, I am hypersensitive to overworking the bow on the tree. I frequently get a bow shooting without taking it past 24" on the tree, and never exceed final draw weight - 10#. I don't think I put as much heat on the stave when I do my initial reflexing.

I've built a few bows with really good "nose" or early weight which started straight and finished with a bit of string follow. Don't know if it was just the odd lucky piece of wood or what. I'm curious to try to duplicate.

George Tsoukalas · « **Reply #7 on:** May 25, 2007, 10:00:35 am »

Sometimes I'll reflex/semi recurve the last 8 inches of a stave right after long string tillering.Sometimes not. Depends on the stave. Sometimes the stave won't take a reflex. For example, if the rings are thin and the stave is twisted and knotted I'm not going to toss in any reflex. Badger, I agree about finding the right width for a stave. I mostly, do it by "listening" to the stave. I start wide. As I tiller I get to a point, where the stave does not respond to belly removal. Then I begin to narrow it. Slowly. All the while exercising it and checking tiller. At any rate, I'm just amazed at the things wood can do.

Jawge

Pappy · « **Reply #8 on:** May 25, 2007, 10:08:52 am »

I do exercise my quite a bit while tillering but never go over intended draw weight and
not close to draw weight in the early stages.I exercise with slow gentle pulls,I have seen some that work them hard and fast.I don't like that.I just make a slow pull down and let right off
and never keep it at what ever length for over a second or 2.Just long enough to look and
maybe a few marks.I also really take my time tillering,I usually do it in 2 or 3 stages.First brace,then out to 12/14 inches and then finish up if it isn't giving much trouble if it is it might take 4 times
with plenty of time in between for it to rest.That has seemed to help a lot as far as set.

Pappy

DanaM · « **Reply #9 on:** May 25, 2007, 11:57:05 am »

Pappy thats dem young ones they go hard and fast,
us older folks know that slow and steady is much better

Dana

DCM · « **Reply #10 on:** May 25, 2007, 12:03:10 pm »

Rest between tillering session is one aspect I practice just out of necessity. I generally get 30 minutes to an hour in the evening and as slow as I go it frequently takes 5 to 10 tillering sessions before I'm done. Of course the last 5 are just very minor tweaking, where it's basically done and I don't take more than a pound or two out of the bow.

Pappy · « **Reply #11 on:** May 25, 2007, 12:10:59 pm »

Ya DanaM that is what my wife says

she also says it always has to go there with you guys.
Pappy

DanaM · « **Reply #12 on:** May 25, 2007, 12:38:12 pm »

She's a wise woman Pappy.

dana

Justin Snyder · « **Reply #13 on:** May 25, 2007, 12:44:24 pm »

I don't usually keep much reflex at all. I have tried more to begin and less to begin. I wonder if it has to do with the length of draw. If you go with DCM's theory that with 1 inch of reflex a 28" draw is the equivalent of a 29" draw. My 2 inch reflex stave would be a 31" draw to the bow. It does add early draw weight, but at the point where the string stops, it quits putting energy into the arrow. So even though it would add a couple of more pounds at brace, it would leave more energy in the bow. If I could just get the brace height down without slapping my wrist. Anyway, back to Pappy's point. I would imagine that the extra stress of extreme reflex making the limb tips travel the same distance as a 31" draw, could be doing damage to the belly cells and making it loose the extra reflex. Kind of like the bow Steve was referring to the other day that started loosing performance after 24". He suspected it was damage to the belly cells.

Well this much I know for sure, I have added 6 inches of reflex and been left with nothing. And I have added 2 inches and been left with 1 1/2". I think I will quit trying to stress the wood so much.

Justin

Badger · « **Reply #14 on:** May 25, 2007, 12:45:26 pm »

I remember several years ago Dan Perry posting that he felt anymore than about 1" of reflex was overkill. I used to think for very high early draw weight reflex was the opnly way to get it. You can have very high early draw weight with no reflex at all, you can end up with a bow building at just over 2# per inch at the end of the draw with zero reflex. My little mass method I use seems to drive the design, kind of takes it out of my hands to some degrees and the bow will take on a shape of it's own depending on the wood and length etc. The bows are comming out quite a bit wider than I used to make them. Demensions more similar to jawges. If you are monitoring draw weight at a level where extending draws does not affect draw weight when you go back to a reference draw point, only shaving wood should affect draw weight, if the bow drops in draw weight just because it was drawn a bit further, then plain and simple, some wood got damaged. This past year since I started monitoring the bows performance at the begaining of the tillering process my perspective of wood has changed 180 degrees. I was getting pretty good performance underbuilding bows and not knowing it. But once I figured out a way to do a better job monitoring my demensions as I built the bow, my bows went to a new level, more durable, and faster. I also found out a wider bow can have less mass than a narrower bow! Not because physics says so but because they can have less dead wood on them. Steve

Primitive Archer