Correct tiller shape

[Kidder]

What is the correct tiller shape for a Hill style American Semi Longbow? 1-1.25 inches at the fades straight taper to half inch or slightly less nocks. Thanks in advance?

[Del the cat]

The correct shape is whatever you want.
Some like stiff outers, some like whip tillered, some like arc of a circle.
For every opinion that says one is smoothest or fastest, there will be an equal and opposite opinion.
Newton's first law of bowmaking? 
The mark of a good bowyer is that the bow ends up the shape that they wanted (doesn't mean everyone else agreed!).
Del

[RyanY]

I think you’ll know the correct tiller because it’ll take low set for the design if it matches the front profile and the bow is designed for the draw weight/length. For example, a pyramid shaped bow that bends too much in the outer limbs will take excessive set there because there is not enough mass to do the work just in the outer limb and the inner limb would need to work more. Of course you can tiller the bow any way you like but set is an objective measurement. People often get away with poor tiller shapes in osage because it can take the bend without taking much set. Those bows are overbuilt.

For your width taper, while it is a pyramid-esque taper, there’s not a drastic enough decrease in width for an arc of circle tiller. It will likely need to be more elliptical in shape. A circular tiller would likely result in too much set in the inner limb.

[Del the cat]

I think you’ll know the correct tiller because it’ll take low set for the design if it matches the front profile and the bow is designed for the draw weight/length. For example, a pyramid shaped bow that bends too much in the outer limbs will take excessive set there because there is not enough mass to do the work just in the outer limb and the inner limb would need to work more. Of course you can tiller the bow any way you like but set is an objective measurement. People often get away with poor tiller shapes in osage because it can take the bend without taking much set. Those bows are overbuilt.

For your width taper, while it is a pyramid-esque taper there’s not a drastic enough decrease in width for an arc of circle tiller. It will likely need to be more elliptical in shape. A circular tiller would likely result in too much set in the inner limb.

He doesn't say if there is any thickness taper!...
IMO all that front profile stuff is irrelevant unless the bow is constant thickness. (I know others disagree  )
This bow illustrates the point.
http://www.primitivearcher.com/smf/index.php/topic,45989.0.html
Del

[Pappy]

  Del I have one of them or maybe that one you gave me the year you came to the Classic, hanging on my wall in the cabin as a reminder.
 Pappy

[RyanY]

Del, not sure what you mean exactly. The thickness taper will determine itself through tillering but we can usually predict what it will look like with some experience. That bow just demonstrates that tiller shapes can differ if we want them to. Doesn’t say anything about performance. How did that one perform compared to a similarly tillered bow with narrower tips? Pretty sure most of us want to get the best performance out of each bow and will tiller to whatever shape necessary. If he wanted to only make a Hill style bow then finding the shape is as simple as looking at pictures of old Hill bows.

I’ll add that the tiller profile for that bow is totally inefficient. It could take an extremely whip-ended tiller with that increasing width towards the tips without taking set and would perform much better.

[bownarra]

Agreed.
The front profile dictating tiller shape is common sense when you think about it
The correct tiller profile for a hill style bow, generally narrow with parallel width for about half the limb length tapering into the tips from there would be quite strongly elliptical. Like an elb's correct shape.
The 'normal' hill bow doesn't have much room to taper in width, like say, a wide at the fades pyramid, so has to taper in thickness quite a lot. I've found taper rates of 0.006" per running inch to be about right. Maybe more. So as the wood thins towards the tips it can safely bend further. Thinner wood should be bending more than thicker wood Elliptical tiller.

[Del the cat]

Del I have one of them or maybe that one you gave me the year you came to the Classic, hanging on my wall in the cabin as a reminder.
 Pappy

Yup, I left that one for you... great memories
Del

[Del the cat]

Agreed.
The front profile dictating tiller shape is common sense when you think about it
The correct tiller profile for a hill style bow, generally narrow with parallel width for about half the limb length tapering into the tips from there would be quite strongly elliptical. Like an elb's correct shape.
The 'normal' hill bow doesn't have much room to taper in width, like say, a wide at the fades pyramid, so has to taper in thickness quite a lot. I've found taper rates of 0.006" per running inch to be about right. Maybe more. So as the wood thins towards the tips it can safely bend further. Thinner wood should be bending more than thicker wood Elliptical tiller.

Knew you'd bite
It's not common sense when you consider stiffness is only directly proportional to width, but is proportional to cube of the thickness.
Del
(It's our running bone of contention folks  )

[RyanY]

Del, I'm giving you the benefit of the doubt here knowing that you are very experienced and maybe we are having a misunderstanding about the original question. Is this a discussion of "correct" being best performance or aesthetic? Maybe that is leading to some confusion. Certainly there is an objective measure of fastest tiller shape for any given width profile with plenty of evidence out there.

[Del the cat]

Del, I'm giving you the benefit of the doubt here knowing that you are very experienced and maybe we are having a misunderstanding about the original question. Is this a discussion of "correct" being best performance or aesthetic? Maybe that is leading to some confusion. Certainly there is an objective measure of fastest tiller shape for any given width profile with plenty of evidence out there.

Thanks, I don't feel in the slightest patronised 
Del

[RyanY]

Thanks, I don't feel in the slightest patronised 
Del

My apologies. Not my intent.

[willie]

Is this a discussion of "correct" being best performance or aesthetic?

A criteria for 'correct' should have been stated in the original question by kidder.

Bownarras response is a good one, but there is an assumption is that correct means to "strain evenly". This is often the advice given to newer bowyers learning how to avoid tillering mistakes.

hill style is often found up to 68 or more inches long. the length to draw ratio affords the bowyer the option of a longer handle area or stiffer tips on either side of the working portions of the limb, these areas and their transitions are of course, not strained evenly.

many who shoot hill bows prefer a soft shooting bow that is easier to aim for using with snap type release when the shooter  first attains full draw. an emphasis is placed on ease of quick followup shots.

Taylor posted this bow recently, and am impressed, but am not a Hill bow guy, so i am not sure if the tiller is typical or not. He did reference a bow made earlier by Ryan that was a source of inspiration. Perhaps Ryan could find a pic of that bow also?

http://www.primitivearcher.com/smf/index.php/topic,69405.0.html
 

[RyanY]

Taylor's bow is better tillered than mine IMO. You can see that the limbs of are somewhat asymmetrical in shape of the bend even in spite of the limb length discrepancy. My bow was not a straight taper to the tips and was more of a gradual convex taper. Here's the description from the old post.

EDIT: Forgot to mention, I think old Hill bows were a bit more elliptical than Taylor's depending on which pics you look at. Certainly there are some that his bow looks to match very well.

The bow is 70"ntn and 45#@28". The handle is 2" deep, 1" wide, and 4 1/4" long. It is 15" fade to fade and the center of the handle is 3/4" below true center to make the upper limb 1.5" longer than the lower limb. The limbs are 1 1/8" wide at the fades, 15/16" at mid limb, and 3/8" at the tips. The bow now holds just over 1.5" of reflex.

[willie]

https://www.primitivearcher.com/smf/index.php/topic,67018.0.html

http://www.primitivearcher.com/smf/index.php?topic=64800.0

here are some more.
I am not picking out SS. it seems google search is not very extensive anymore, maybe the server change?

lots of hills made with glass, but those guys never seem to show FD pics. I have been looking at hill style tiller quite a bit, as it seems some complain of the style having excessive handshock, or at least if not tillered properly. what makes for a damp shooting hill is not quite easy to locate. maybe its more a glass bow problem?