Tillering a reflex/deflex bow

[Skimo]

I am in the process of building a reflex/deflex bow and am at the longstring tiller. I have romoved 60 (15 at a time) scrapes from both limbs and the wieght has not come down much at all if any. I would like some advice on whether or not this is normal. Should I just keep scraping away and it will eventally get there, or is there something else I should do?
I would also like your opinions on the tiller, I sometimes have a hard time being subjective, and my first bow(this is my second) came in at 25lbs at 28". I am aiming for 45 to 50 lbs at 28 inches. The bow is 72" tip to tip, red oak backed with Aspen (don't ask me why, it just is  ). The limbs taper from .6 inches at the handle to .5 inhes at the tips and the width tapers from 1.5 inces at the handle to about 3/4" at the tips. I plan on narrowing the tips but wanted to leave some play for centering the string as my first bow developed some side bend in the limbs and is slightly off center.

So here is the bow in the tiller relaxed


Here it is at 30lbs and pulled 7 inches.


I really don't want the bow to come in underwieght, so I am only removing 15 scrapes at a time, which equates to about .02 inches each session. Is this normal? I also wondered if I should be pulling the bow to 40lbs?

Just thought I would throw in a picture of the scaper so you could see what I am doing and tell me if I should change anything.


Thanks,
Skimo

[ken75]

looks like your gettin most of your movement in the fade and some at midlimb i think i would go ahead and narrow my tips and see if i couldnt get the whole limb working . most of the time i like my recurves to open up at the last few inches of draw but your reflex is just beyond midlimb and is causing from there out to not begin working. good luck hope it becomes a great shooter

[Jesse]

What Ken said. The part where you put your clamps is gonna be real stiff. I would shorten that string so you can barely get it on without bending the bow.  Get the limbs working and even and then brace it. You might be surprised at the draw weight.  Reflex like that makes it seem heavy at first and can trick you.  Never heard of using aspen for a backing. If its like our aspen here its on the week side so I would try to get it down in draw weight to the minimum you will be happy with.  Sometimes it takes a lot of scraping and little changes but as you get out near full draw things change very easy so just keep going slow the whole way and dont talk yourself into thinking the tiller is ok until it is. getting a good tiller is more important than draw weight.   Looking forward to seeing it done

[aznboi3644]

i think the oak will overpower the aspen...maybe try slight crowning the belly

[medicinewheel]

Sorry to say that: stood next to a elm backed bulletwood children's bow when the backing failed. Didn't sound nice. This will be the same most likely. If aspen was ANY good for anything you would have had it mentioned some place.
I'm sure someone would provide you a nice piece of hickory for your next...

PS: trapping towards the belly is probably not a solution; will be very difficult to control balance I'd say.

[Skimo]

Thanks for the responses.

OK, I will go ahead and narrow the tips and concentrate on getting that part of each limb working. Ya the Aspen is soft but has a very stringy structure, I thought it would be good in tension and help to keep the oak from popping splinters. The aspen is only 1/8" thick so I don't think it is adding much, if any, weight to the bow. The oak is doing most of the work. What would crowning the belly do? I thought crown in the belly was a bad thing from what I have read, but I admit I know very little about it.

Thanks again for your help. I will post pics of what I get done tomorrow. Really appreciate your input.

Skimo

[Del the cat]

Nice looking bow.
it looks like you know what you are doing.
My only suggestion would be to make the support on your tiller tree, shorter and slightly rounded, just to allow the bow to move on it's own more.
Some people clamp the bow, but to me that gives a false impression and can hide some imbalance.
Glad you liked my tillering vids. Of course the flatbow I'm doing is very different to your backed bow, or a longbow where you wouldn't touch the back (or do very very little to it)
Del

[Mark Anderson]

I don't know much about tillering an R/D but those horns in the background sure look nice!
Mark

[aznboi3644]

Skimo I only recommended crowning/trapping the belly to take some work load off of the back and help prevent a tension failure from the aspen.

[Skimo]

Thanks for all the comments.

Del, I noticed that on your tillering tree in your videos. I have been thinking about modifying the support on the tree, thanks for your input.

Mark the horns are the work of my good friend Tim Crosby who has graciously allowed me to use his shop for my bowmaking. He is quite the artisan and also makes black powder long rifles.

Aznboi thanks for the explanation, I appreciate your input and will keep that in mind.

So I narrowed the tips to 1/2" and have not removed any more wood from the belly of the bow.



I shortened the tillering string (thanks Jesse) and pulled the bow 9" to 40lbs on the tillering tree. In the photo the scale is not in the loop because I pegged the string so I could really look over the tiller. Del, ya you can see I have a clamp built into my tree, but i don't use it much, I find it gives me false readings just as you said.



It looks to me like the tips are working more now, but still not enough, so I will probably very carefully remove some wood from the last quarter of the limbs to get more movement there.
I spent the rest of the day putting horn tip overlays on the bow (One great advantage of working in a horner's shop is there are lots of horn tips laying around ) Here's a photo of the overlays, you can kind of see some of Tim's rifles in the background.



Thanks again for all your help everybody.