Red oak short bow for son - tiller issue

[doggonemess]

Greetings again,

I'm well into my second bow, which is a red oak short bow, linen backed, about 5 lbs at 18 inches. The linen came from one of my wife's old shirts that she put aside. (Please don't tell her, I want to live to see 40.  ) It's going well, shoots very nicely, but I discovered a tillering issue that I can't seem to correct. I wanted to check with the forum before I end up sanding the thing into oblivion.

The bow has more bend on one side than the other, but I can't seem to even it out. The side that bends more is actually about 0.5 mm thicker along most of the length. I know the wood could very easily be stronger or weaker regardless of thickness, but no matter what I do, it just doesn't seem to want to bend to match the other side.

This is the bow after what I thought would be the final sanding:


Because of the poor lighting and contrast, I made a version with the background saturation lowered and added an example curve:


Here I have the bow at full brace, and you can see the issue. At full draw (a whopping 19 inches  ) it's terrifying. It looks very unbalanced and I worry that it would break eventually due to the uneven stresses.

Can someone diagnose this guy? I'd love to finish it so my son can start. After this, I'm making a bow for my wife and another for my daughter. My wife's will be white maple, my daughters will be another red oak bow.

I've already made some arrows. I used dowels (since a 5 lb bow isn't going to break a dowel) and did my own fletching using colored goose feathers. The arrows are great! I'll need to take a picture later. I used a technique where you build a little box with two holes in it, and then cut slits for the feathers, which hold them down while you wrap them. I didn't even need glue. I'll post a different writeup about that.

Thanks!

[toomanyknots]

I totally did not read any of your post ( , just to let you know) but from first glance at your picture, I would say that the tiller/bend of the limbs is just fine looking from the braced position, it's just that the left limb is a bit stronger than the right. I would suggest just evenly removing wood from the left limb, maybe just with some 100 grit sand paper or something, and than checking out the string height at brace on each limb. I would keep removing wood from the stronger limb, than exercise/brace the bow, and put your hand with you thumb sticking up on the belly of the bow when braced to see how high the string is from your thumb on one limb, than check the other, repeat until the string height is as close to even as you can get it (or like it). It's not a big deal for the bottom limb to be a bit stronger anyway, most bows have a slightly stronger bottom limb and shoot better like that.

[Del the cat]

Looks ok, but we need to see the full draw (or drawn as far as you've taken it).
It can happen as you describe, taking some off the stiffer limb near the grip will help, that fade area looks a bit long and stiff too me. The inner half of that left limb doesn't seem to be flexing at all.
But like I said, that's why we need to see it at draw.
As you weaken that limb it will take some of the load off the other limb which will then bend less.
I'd suggest a scraper or file (or fine rasp) rather than sandpaper, being solid it gives better control (just my opinion)
Del
BTW The tiller on low draw weight bows can be very twitchy as you have so little draw weight to play with and just moving the bow slightly on the tiller (or mving the draw point on the string) can have a marked effect.
I'd rather tiller a 40# that a 20# any day.

[Baldmoose]

make sure to use the limb that appears a little stronger for your bottom limb as the bottom limb is usually stressed more.

[doggonemess]

I'm learning that tillering this bow is actually harder than the first one I did. I'm really surprised about that. A tiny bit of material makes a huge difference. I went from perfect to a huge hinge with one removal. I'll just work it carefully until it bends a little more.

I'll take a photo in a bit at full draw. Thanks!

[doggonemess]

Here is the bow at full draw. The red ellipse shows a nice even curve to my eye, which I was surprised about. The blue line shows that the difference in height between the knocks is only about 3/4 inch. Should I go ahead and finish it?

[Baldmoose]

I notice the right limb at the fades isnt bending as much as the left limb. Not sure if its just my eyes.  barely noticable.  Great job on the bow by the way. 

[Stefan]

It looks a bit whip ended to me. I would remove more wood around the fades. I'm certainly not an expert, but if you want to go from 20 inch to 26, 27 or 28 inch I should remove wood around the fades and make the stiff section shorter. If you are ok with the 20 inch of drawlength I would sand it and keep it as is.

greetings

stefan

[doggonemess]

I'll check the ends again, just to be sure. I think I trend towards whip ended most of the time.

One thing - 20 inches is my target for the draw. The bow is for my five year old son.

[randman]

What does the limb profile look like. That tiller might be fine (with a little more bend in the fades) if the limbs are parallel most of the length. How wide are the limbs @ fades / mid / tip?

[flungonin]

WoW, Looks really good.  Sand and finish. Y

[doggonemess]

What does the limb profile look like. That tiller might be fine (with a little more bend in the fades) if the limbs are parallel most of the length. How wide are the limbs @ fades / mid / tip?

The bow is about 1/2 inch wide at the grip and tapers very slightly down to about 3/8 inch at the nocks. As it is designed to fit in my son's hand, it had to be very slim for him to hold it properly. My first bow is 1 3/4 wide at the grip and tapers to about 1/2 inch, so I had a lot more control over the tillering I think.

[doggonemess]

WoW, Looks really good.  Sand and finish. Y

Thanks! I'm going to start tonight I think. I'll probably just do some BLO on the wood and leave it au-natural. The grip I'm going to wrap with some green leather that I have lying around. It definitely needs an arrow rest as well.

[doggonemess]

I've finished fine sanding and am ready to seal it. I'm going to use BLO, since I'm familiar with it from restoring a Martini-Henry stock. I do have a question about using it on bows. I'll post that in a separate topic, though, as it stands alone very well, I think. I'll post some pictures once I finish the BLO and handle wrap.

[ken75]

for future reference the problem was in your last 6 inches of your right limb . it thinned and whipped further than the other