How do you guys know tip dmensions?

[DuBois]

I find myself wondering how to decide how thick and wide to make tips on any given bow I may be trying to make and also how far up from tip to stay stiff.
If there is a non bending section toward the end of limb, how do you experienced bowyers know just how thick to go and where to start tapering it from bendy to stiff?

I have been wondering this more since doing my first 3 sinew bows that are not finished yet. I want to wrap sinew on non bendy areas of tips but the bow is not tillered yet and I don't really know how much wood I can get away with removing before wrapping.
Don't want to leave it too heavy but of course don't want to break either.

I'm sure this comes with experience but is there a way to have a better idea than my current, "looks about right I guess".

Thanks All,
Marco

[DarkSoul]

Get an accurate scale and an accurate tiller tree set up. Then remove wood from the tips, until the draw weight drops by 0.1 pound.

Bending tips actually translate to very little loss in draw weight. A little bit of bend in the tips, equal little tip deflection, while a bit of bend in the handle fade gets multiplied by the limb length and translates to a lot of tip deflection. "Keeping the tips stiff" is somewhat of a subjective term. Theoretically they can never be completely stiff, they always bend some micrometers. It is also subjective where the bending limb ends and where the stiff tip starts. In general, I think the last five inches of my tips are usually tillered to be stiff. The exact dimensions are indeed based mostly on feel, something that will come with experience. You'll be amazed how narrow you CAN theoretically make the tips! But that comes at the cost of fragility. Obviously, stiff woods such as ipé should result in dimensionally smaller tips than soft woods such as Eastern red Cedar/juniper.

[Slackbunny]

What would be the purpose of wrapping sinew on the tips? Adding weight that far out on the limb will lower performance. But if you need the sinew there for something or if you just really like the look then have at it. Just know that there is a compromise.

I like to make my tips about as big around as my finger. I've seen some guys go as small as a pencil, but I'm not that brave.

Yes there should be a non-bending area at the tips, but its not very long, maybe 3 or 4 inches? Someone more experience should weigh in on that one.

[rps3]

I like the last 6 inches to not bend much. With sinewed bows, I wrap the sinew about 6 inches down from the tips while they are still fairly wide.  Tiller the bow as you normally would, and after you have it bending like you want with the tips stiff, thick, and fatter than you like, file them down as much as you dare, the re-wrap with sinew, at your 6 inches down.

[MWirwicki]

The only reason that I might wrap a sinew bow's tips is if I've flipped the tips a bit before sinew.  I've had sinew shrink in the curing process and pull up from the depth of the curve.  I wrap the valley of the tip sometimes to prevent this.  My glue held in those cases, it pulled a layer of wood with it.  I've never thought of wrapping the entire length of the tips.  I never saw this as necessary.

Again, this is what works for me.  Not that any other way is incorrect or anything...

[DuBois]

You guys are awesome!
Thanks for the wisdom.
Marco

[rps3]

MWirwicki , I do just like you, but my sinew ends where the stiff tips start, then just a couple simple wraps of sinew around so it doesnt pop off.

[Pat B]

I do the same as rps3 does and wrap the ends of the sinew but I've only built a handful of sinew backed bows. Matt however has built many so I take what he says about this as gospel. I'll probably still wrap the ends of the sinew because I like it. 
  Dubois, leave the last 6" of the limbs at least 1/2"x1/2" until the tillering is done. At 1/2" thick you can reduce the tip width considerbly  to reduce excess tip weight. I usually make the finished tips on my bows about 3/8" wide at the string groove or less. You would be amazed how small you can actually make the tips of a bow of 60# or so.  If I'm not mistaken I believe the tips of the English(Welch) war bows were about 1/2"x1/2".

[dwardo]

Like some others have said it a mix between experience and confidence. After that its durability.

I look at some of my past bows and I have some that are super skinny at just over a 1/4 wide and some over 3/8.
I would guess i could get even thinner but as most of my shooting is done whilst playing in the woods I dont want to have to baby the bow all the time to avoid breaking a tip. Like most else here the last thing I do after tillering is start to narrow the very out limbs and tips.

[DuBois]

Like some others have said it a mix between experience and confidence. After that its durability.

Like most else here the last thing I do after tillering is start to narrow the very out limbs and tips.

This is really helpful to me, Thanks

[DuBois]

So with an ash bow about 50# and 65" long, is 3/8 wide by 1/2 thick adequate?