Author Topic: Tillering advice deflex reflex bow.  (Read 3994 times)

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Offline gfugal

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Tillering advice deflex reflex bow.
« on: January 12, 2019, 09:11:25 pm »




So I have this honey locust bow that is I believe 66" long that I put some deflex reflex in. I ended up getting a little more reflex than I wanted and less deflex. I have started tillering it on the long string and am getting closer to bracing it. I'm aiming for 40 lbs at 28" but I want to tiller it out to 29". My question is how does the tiller look so far? This is my first deflex reflex bow, and I'm am unsure how exactly the limbs should be bending. I have heard that they should be mostly straight at brace, with just a little bit of the reflex still present. However, I'm not to brace draw yet and it already looks straight. So does that mean the mid-limb is working too much? I would just like more experienced input before I continue.
Greg,
No risk, no gain. Expand the mold and try new things.

Offline gfugal

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Re: Tillering advice deflex reflex bow.
« Reply #1 on: January 12, 2019, 09:13:34 pm »
I should mention that right before the fade on the right side there is a hump on the back of the bow, so I think it throws off the bend right next to the fade a bit.
Greg,
No risk, no gain. Expand the mold and try new things.

Offline Badger

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Re: Tillering advice deflex reflex bow.
« Reply #2 on: January 12, 2019, 10:40:50 pm »
   With that profile you should be showing a pretty good arc at brace, not straight. I would get the mid and outer limbs working just a tad more.

Offline gfugal

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Re: Tillering advice deflex reflex bow.
« Reply #3 on: January 14, 2019, 09:54:58 pm »
Thanks for the reply. You say with that "profile" it shouldn't have reflex left, not even straight. I figure that means it's because of where the reflex is, being closer to mid lim, that the bow has to bend there more than if it was say in the last 3rd or 4th of the limb where it can remain stiffer. I will take your advice and work the mid and outer thirds just a tad bit more and get it bending more smoothly
 
Greg,
No risk, no gain. Expand the mold and try new things.

Offline gfugal

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Re: Tillering advice deflex reflex bow (Now Braced).
« Reply #4 on: January 26, 2019, 03:48:59 pm »


Here the bow is braced at around 5". (fun fact, I braced it using the long string and an additional cord cinched tight with a truckers/taught-line hitch combination. I have always been weary bracing bows at first because you have to pull the limbs much further than the brace distance to get the string on the nock and to accommodate for string stretch. This way I bypassed that to some degree). It may be hard to tell but the top limb (pictured right) is actually stiffer than the bottom limb (pictured left). I've measured the distance from the string to the limb and they are pretty close. It also complicates things since I made the limbs asymmetrical, the top is an inch or two longer, can't remember exactly. I can see the bend is different on the top limb, it's more straight than the bottom, but I don't know how much that is due to the limb being longer with reflex in a different spot.



The bow is tilted a bit because the center line is off-center toward the top limb (right). When the bow is braced the string is level and the limbs travel the same distance, and the distance from string to the limbs is pretty close, as I mentioned before. However, It probably does have an issue with it's tiller as it has gotten some set compared to the other limb.



You can see they are pretty close with reflex, but the top limb is a little less. The top is 6 cm of reflex, and the bottom 7.6 cm. the top limb used to be just slightly more reflexed than the bottom, so I definitely got a bit of set.

Where do you guys think I should adjust?
« Last Edit: January 26, 2019, 10:54:08 pm by gfugal »
Greg,
No risk, no gain. Expand the mold and try new things.

Offline NorthHeart

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Re: Tillering advice deflex reflex bow.
« Reply #5 on: January 26, 2019, 09:28:36 pm »
Hi gfugal. I don't know if its just me but i can only see your first pic, and not the other two.

I am posting a pic of where i think you might remove material(in my opinion). Please don't follow it until you get other's advice first.

The big question i've always had, and never got a consistent answer to, is do you always remove material in order to make the limb bend evenly both across itself and as compared to the other limb(here's the important part)...even when the wood is getting skeptically thin in that area??

ps-forgive my screenshot it said the other file was too large


Offline gfugal

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Re: Tillering advice deflex reflex bow.
« Reply #6 on: January 26, 2019, 10:57:45 pm »
I tried to fix it, so hopefully it will so them now. But I agree, the middle and outer portions of the top limb look like they need to bend more, however, It does seem awfully thin. Especially right where the first big arrow you drew is, and that looks like the spot it needs to bend the most. It's always confusing when the wood seems to say one thing but your reasoning says another. Does anyone know how to handle that? just do what the wood says, no matter how thin it gets?
Greg,
No risk, no gain. Expand the mold and try new things.

Offline DC

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Re: Tillering advice deflex reflex bow.
« Reply #7 on: January 27, 2019, 09:08:02 am »
Is your top limb to the right in all the pictures? If so I think your top limb has more reflex bend than the bottom limb and that's making it look stiff. Trace the unbraced outline on a large piece of paper and then swap ends and look at it. See which limb has more reflex bend and then either steam one to match them up or keep in mind that the one with more bend will look stiffer. RD's are tough to tiller because your final curve depends on what you started with. There is no right shape with an RD if you understand what I mean. I believe that you want an even bend just like you do with a straight bow but you have to keep in mind what you started with.

The reason I called it a reflex bend is that you can have more bend in a limb and still have less total reflex in that limb. That wiggle in the bottom fade could be messing with your eyes.

Offline gfugal

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Re: Tillering advice deflex reflex bow.
« Reply #8 on: January 27, 2019, 12:04:47 pm »
Is your top limb to the right in all the pictures? If so I think your top limb has more reflex bend than the bottom limb and that's making it look stiff. Trace the unbraced outline on a large piece of paper and then swap ends and look at it. See which limb has more reflex bend and then either steam one to match them up or keep in mind that the one with more bend will look stiffer. RD's are tough to tiller because your final curve depends on what you started with. There is no right shape with an RD if you understand what I mean. I believe that you want an even bend just like you do with a straight bow but you have to keep in mind what you started with.

Unfortunately, the bow is made from two spliced billets so I can't really redo it very easily. I think I'm going to just keep an eye on it. It does make it tricky if the two reflexes aren't exactly symmetrical. Thanks for the advice.

Quote
The reason I called it a reflex bend is that you can have more bend in a limb and still have less total reflex in that limb. That wiggle in the bottom fade could be messing with your eyes.

I should mention that right before the fade on the right side there is a hump on the back of the bow, so I think it throws off the bend right next to the fade a bit.

I should mention that that wibble or hump/wiggle I describe is now on the left side. It's on the bottom limb. Sorry I switched limb directions cause it worked better with string alignment when tillering. The first two pictures in my post had the top limb on the left, and my latest post of it braced had the top limb on the right. The hump/wiggle is now not pictured as it is primarily on one side, the side facing away from the camera on the left. Again I apologize I forgot I switched them, or I would have switched it back before taking the picture. I know that makes it confusing. Do you still think it might be throwing it off? I will take a closer look at that section just to be safe though, thanks!
Greg,
No risk, no gain. Expand the mold and try new things.

Offline DC

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Re: Tillering advice deflex reflex bow.
« Reply #9 on: January 27, 2019, 12:15:25 pm »
I doesn't really matter where the hump is just remember that it's there and can affect how you're seeing things. Making a tracing of the bow really helps you see what's what.