Front profile/tiller shape

[JonW]

So if a guy were to splice a bow in the handle with one limb being parallel design and the other limb being pyramid design what should the tiller profile be? 

[BowEd]

I'll bite.How long Jon?Hand shock amoondoooo....lol.... but maybe not too.Depending on length of bow.Would'nt you have eliptical on one and full circle on the other?If you've already got it done you should show us....lol.

[PEARL DRUMS]

I made a buckthorn bow that has a straight lower limb and an RD upper limb. I tillered each according to its respective shape. The bow is smooth and sweet. Just looks goofy is all.

[JonW]

Ed I was helping a guy recently with a bow. The stave was characterish providing only the front profile described. I said tiller each limb respectively but alas peer pressure took hold and the guy tillered the bow to a perfect brace and tiller profile for a circular bend. I'm not saying I was right exactly but just pointing out that people don't often consider all things respectively trying to attain a preconceived notion of what full draw should look like.

Chris everyone convinced him that it would look goofy so he caved in.

[BowEd]

Well as long as it shoots nice and feels good in the hand that's the bottom line,but did 1 limb take more set than the other?

[Del the cat]

Front profile has nothing to do with tiller shape  .... (yeah I know some will disagree...)
Check out this one:-
https://bowyersdiary.blogspot.co.uk/2017/03/the-frankenbow.html
Del

[JonW]

Yes it did Ed. Guess which one and why?

Del so why do we have different tiller profiles?

[Badger]

Front profile has nothing to do with tiller shape  .... (yeah I know some will disagree...)
Check out this one:-
https://bowyersdiary.blogspot.co.uk/2017/03/the-frankenbow.html
Del

  Del, I would agree that you can get a nice round tiller out of any front profile but if you are looking to optimize the performance and keep the wood in good order the front profile has everything to do with the tiller shape. Not that I always follow that myself but it is what I shoot for.

[PatM]

In typical bow lengths  the degree with  which tiller matches front shape  would be interesting to compare between extremes.   

[Del the cat]

Just sayin'  Pyramid... Dimaryp
At the bottom of this entry on my blog.... That miniature bow is on Pappy's cabin
https://bowyersdiary.blogspot.co.uk/2014/04/ashbow-re-try.html
Del

[BowEd]

Yes it did Ed. Guess which one and why?

Del so why do we have different tiller profiles?

Good question.....Well set means too much wood removal or asking the limb to do more than it can with the design than what it's got for the draw weight poundage it's got.Wheeeooo!!!I hope you can get ahold of that one....lol.If he tillered it circular what would that be.....Hmmmmmm.Jon....You got me on the line but I'm not in the boat yet.....lol.

[willie]

if one chooses to tiller dissimilar profile limbs to a common shape, than one limb will be strained harder than the other. whether it is overstrained and takes set is a different matter. Note that Dell balanced his tiller by tillering the stronger limb down to match the weaker. In order to guess which limb took set, one would have to know which limb was the stronger of the two.

the question is a good thought exercise, though.

[JonW]

I'm not saying I have a good solid opinion. I have always struggled with the idea of tiller vs profile thing. In the end I guess the set will tell you where you went wrong.

Ed the pyramid limb took most of the set. I was hoping you could tell ME why lol. Pyramid limb was top limb by the way.

I have way more questions than answers!

[BowEd]

Honestly I was going to say the parallel over powered the pyramid because more wood is available width wise at the same distance on the limb to work more so than the pyramid,but since it was circular tillered I was apprehensive as to how thin he made the parallel limb to match the pyramid.Makes sense though.Now you did'nt say what types of wood they were either.If they were different or the same etc.Some woods are more different design worthy than others.More balanced so to speak with tension and compression qualities.
Well wizard you can take away my hands on experienced teaching certificate away from me now.....lol.Ha Ha Ha.
To get something straight here is a pyramid considered an AFB?I know parallel limbed bows are.

[Del the cat]

Yes it did Ed. Guess which one and why?

Del so why do we have different tiller profiles?

We have different profiles to suit the wood, but the profiles basically only have two types wide and thin or narrow and thick. (let's ignore the Molle'  )
There isn't a vast difference in front profile unless you go to extremes like paddle bows. A bit of width taper is neither here nor there as width is vastly less important than thickness.
IMO cross section is prob' more important than front profile.
You choose the cross section to suit the wood,
E.G. With Hazel and many other white woods one would favour a wider thinner design, or if you want to go narrow, you'd probably go lower poundage or trap the back.
So, take a wide flat profile at 2" wide... you could leave it 2" wide all the way along the limb, but it would be a pig to make sensible nocks... so you taper it a bit at the tips. But do you make it a leaf shape or a true pyramid or just taper the last 6"?
It doesn't make much differnce, 'cos by the time you've blended it in, they will all look similar.
What shape do you tiller it to? Whatever takes your fancy! I tend to go arc of a circle, 'cos it's easier to define and check. Others like some undefined "ellipse" each to his own... but to be honest I don't see much correlation between front profile and tiller shape, I think the differences are minimal.
But like I say others have their view, and that's the joy of this forum...no cussing and insults, we each argue our case.
The only problem is, it'd be more entertaining over a beer  .
Del