Tiller shape vs front profile

[mmattockx]

Do you have a simple flat bow design for Hickory boards that can shoot 170 FPS with 10 GPI arrows?

Not yet, but then I haven't tried, either. How long is the bow, what draw length and what weight?

Does anyone have the front profile and thickness tapering chart printout for such a bow?

It is more complicated than that. You need to match the dimensions to the characteristics of each piece of wood along with the bow length, draw length and draw weight. Not every piece of wood will give you that performance, either.


Mark

[scp]

Are you asking this because you’re truly interested in if there’s a reliable method or for some other reason?

I have built at least 50 bows. Most of them took me just several hours as I don't even bother to sand them. The earliest handful took me days if not weeks and they are still my better bows. If you want pictures as a proof, how are you going to verify that I did not take pictures of someone else's workshop? Many people seem to have lost all sense of honor, trust, and integrity somehow. I live and die on my words, at least in my mind. And I am also quite good at telling whether or not a person is lying or not, by just reading his posts. I simply ignore liars and cheats, unless I am interested in their pathology for whatever reason.

As for the Woodbear's bow, it is much better than my best bows, but you said it was actually tillered by a master bowyer called Badger! I have no verified 170 FPS bow, as my release through the chrono is so terrible. I shoot the purchased fiberglass recurves through it, and get around 160 FPS only. Most of my good bows shoot around 150 FPS on a good day.

I am not against math and physics as tools, other than that I think they are better at destruction than at creation of life forms. Therefore I don't trust them in the matter of the meaning of life. They will eventually be used to make robots that can replace all master craftsman, artists, and even doctors. But they should not be allowed to dictate the meaning of human life.

Here I am mostly interested in getting ordinary language "principles" to achieve perfect tillering. I want them to have some explanatory powers to help us understand how bow making with natural materials works. I find the mantra and the mass principle quite useful but not very satisfying. Not good enough at giving me the illusion of deeper comprehension, at least not anymore.

Bow making is just a hobby for me. All I want is to be able to talk about bow making, using just ordinary language words but still intelligently enough to get better at it somehow, without the need to learn anything with a stiff learning curve.

[scp]

Do you have a simple flat bow design for Hickory boards that can shoot 170 FPS with 10 GPI arrows?

Not yet, but then I haven't tried, either. How long is the bow, what draw length and what weight?

Does anyone have the front profile and thickness tapering chart printout for such a bow?

It is more complicated than that. You need to match the dimensions to the characteristics of each piece of wood along with the bow length, draw length and draw weight. Not every piece of wood will give you that performance, either.

Mark

My current go-to design is a hickory stave bow that is 68 inch long, with 10 inch stiff handle, 1.75 " wide at fade, flat pyramid limbs, and 8" stiff and straight tips. Sadly my preferred draw weight is just 30 pounds now, at 28" draw length. Mildly heat treated belly with hopefully almost no set. Limbs are usually too thin to be trapped.

I usually get just 150 FPS. I like to get 170. If someone gives me a thickness chart for perfect tillering of this bow, I am willing to get the caliper out and actually use it. Thanks.

[Don W]

Well....it took 10 pages but I believe these two link will get me closer to understanding. A great original question.

https://www.virtualbow.org/

https://www.tapatalk.com/groups/paleoplanet69529/woodbear-s-red-oak-entry-t13237.html

Thanks for those!

Now if someone can just help me remember how to shot like I did when I was 16!

[RyanY]

I have built at least 50 bows. Most of them took me just several hours as I don't even bother to sand them. The earliest handful took me days if not weeks and they are still my better bows. If you want pictures as a proof, how are you going to verify that I did not take pictures of someone else's workshop? Many people seem to have lost all sense of honor, trust, and integrity somehow. I live and die on my words, at least in my mind. And I am also quite good at telling whether or not a person is lying or not, by just reading his posts. I simply ignore liars and cheats, unless I am interested in their pathology for whatever reason.

As for the Woodbear's bow, it is much better than my best bows, but you said it was actually tillered by a master bowyer called Badger! I have no verified 170 FPS bow, as my release through the chrono is so terrible. I shoot the purchased fiberglass recurves through it, and get around 160 FPS only. Most of my good bows shoot around 150 FPS on a good day.

I am not against math and physics as tools, other than that I think they are better at destruction than at creation of life forms. Therefore I don't trust them in the matter of the meaning of life. They will eventually be used to make robots that can replace all master craftsman, artists, and even doctors. But they should not be allowed to dictate the meaning of human life.

Here I am mostly interested in getting ordinary language "principles" to achieve perfect tillering. I want them to have some explanatory powers to help us understand how bow making with natural materials works. I find the mantra and the mass principle quite useful but not very satisfying. Not good enough at giving me the illusion of deeper comprehension, at least not anymore.

Bow making is just a hobby for me. All I want is to be able to talk about bow making, using just ordinary language words but still intelligently enough to get better at it somehow, without the need to learn anything with a stiff learning curve.

Turns out if you actually read the quote, all Steve did was pull the bow further than the intended draw weight. How can you possibly judge people as liars on the internet if you missed a point like that? Glad you finally came out about your bias against math and physics tools. Your excuse for not sharing your own work further adds to your bizarre character. You have no credibility that I can discern. Your last statement about not wanting to take on anything with a steep learning curve speaks volumes.

[scp]

I would not buy a six digit price tag farm tractor to tend my tiny 4x8 raised vegetable garden. But I would definitely buy the best hand tools I can afford. For most hobbyists here, even TBB1 is not particularly recommended. Just get Jim Hamm's 84 page booklet and a sharp hatchet, and go for it.

As for "matching" the working limb thickness profile with the front width profile, just look for a graceful line of bent limbs, as bow makers have done for thousands of years. If you like to look are shapely girls or boys, you will have no problem there. Just make sure you are looking at a person mature and powerful enough to handle you.

Now I am looking for a way to appreciate the limb thickness changes of an unstringed bow and figure out how beautiful they will be when the bow is braced and drawn. Any ordinary language heuristics would be more than welcome. Thanks.

[mmattockx]

As for the Woodbear's bow, it is much better than my best bows, but you said it was actually tillered by a master bowyer called Badger!

David Dewey made that bow based on his spreadsheet design, never bent it to more than ~10" draw length and then sent it to Badger for testing. Badger then exercised it on the tree while working the draw length out to 28". He never touched the bow aside from drawing it. It was that thread that convinced me a bow can be designed mathematically and work well. Learning to use David Dewey's spreadsheet is a bit of a struggle but it has given me accurate results to date.

They will eventually be used to make robots that can replace all master craftsman, artists, and even doctors. But they should not be allowed to dictate the meaning of human life.

That's an interesting take on it, but is well OT for this thread.

My current go-to design is a hickory stave bow that is 68 inch long, with 10 inch stiff handle, 1.75 " wide at fade, flat pyramid limbs, and 8" stiff and straight tips. Sadly my preferred draw weight is just 30 pounds now, at 28" draw length. Mildly heat treated belly with hopefully almost no set. Limbs are usually too thin to be trapped.

I usually get just 150 FPS. I like to get 170. If someone gives me a thickness chart for perfect tillering of this bow, I am willing to get the caliper out and actually use it. Thanks.

For that design you will want no thickness taper at all. Maybe run the limbs parallel for ~2" out of the fades and then taper straight to narrow knocks (how wide are your nocks?). You may not get 8" of stiff tips that way, but certainly the last 5-6" will not bend much. The short parallel section gives you a bit more leeway when trying to get a smooth bend into the fades. I have found it is easy to get a bit of a hinge going right at the fades when you start the width taper immediately out of them. Somewhere Badger suggested the short parallel bit and it worked well on my last bow.

I have seen comments about it being hard to get light bows very fast based on the 10gpp formula, perhaps that is some of your issue with getting as fast as you want. If you want more speed I would suggest making the bow narrower at the fades to get more thickness to the limbs (higher strain levels are more efficient until you get set) and heat treating a bit of reflex in for more early draw weight. Even moving the tips 1" forward of the handle makes a very noticeable difference in early weight and is not very hard on the limbs.


Mark

[scp]

To Mark: Thanks for the useful observations.

I guess exercising a bow properly is a part of tillering.

For my flat pyramid bows, most tillering is done on the band-saw. Working limbs are basically all same thickness for the full length. After that I just scrape from the fade to the beginning of stiff tips in long even strokes, until I get to the desired poundage.

I do make the handle and fades longish, often over 12 inches in total, but sometime I forget and make the fades too short and cause a hinge there. Starting at 2" from the fade sounds very reasonable for that issue.

I do reflex the working limbs about 2 inches while heat-treating the belly. Usually about 1 inch is left after shooting it several dozen times.

All these are very nice, but too specific and without much explanatory power. I would love a more generalized mantra that incorporates the mass principle into each sections of bow. You started on that route but got distract by the effect of thickness and width taper on the total mass.

How about a new thread for this newer mantra? I do not start one because I cannot promise to follow through to its natural conclusion. Thanks.

[willie]

I have seen comments about it being hard to get light bows very fast based on the 10gpp formula, perhaps that is some of your issue with getting as fast as you want. If you want more speed I would suggest making the bow narrower at the fades to get more thickness to the limbs (higher strain levels are more efficient until you get set) and heat treating a bit of reflex in for more early draw weight. Even moving the tips 1" forward of the handle makes a very noticeable difference in early weight and is not very hard on the limbs.


Mark

I agree.

I do reflex the working limbs about 2 inches while heat-treating the belly. Usually about 1 inch is left after shooting it several dozen times.

perhaps your reflex loss has more to do with your heat treating method and not necessarily indicative of the limb being stress hard enough to create set.

[mmattockx]

All these are very nice, but too specific and without much explanatory power. I would love a more generalized mantra that incorporates the mass principle into each sections of bow.

Ah, I understand now. Arvin (Selfbowman) and I discussed that some and he is also looking for an optimum distribution of mass along the limb for his flight bows. I have nothing to offer there yet as I don't have enough bows made using analytical design to be able to cross reference the final performance with the design parameters.

Maybe one day I will get there but I have lots of other hobbies and things that fill my days, leaving me with minimal time for building bows in quantity. Currently work is busy and we are in the middle of building a new house out in the country. Once that gets put to bed I should be able to dedicate more time in the wood shop to some lam bow experiments I started on over winter. The first try was a failure due to glue related issues, but attempts will continue until a conclusion is reached.


Mark

[willie]

he is also looking for an optimum distribution of mass along the limb for his flight bows.

is this another way of asking how much a "stiff" tip can bend, and still be effective as a lever?

[scp]

I do reflex the working limbs about 2 inches while heat-treating the belly. Usually about 1 inch is left after shooting it several dozen times.

perhaps your reflex loss has more to do with your heat treating method and not necessarily indicative of the limb being stress hard enough to create set.

Quite possibly. In this kind of situation, I am not actually trying to reflex the limbs for sure, hence "mild" heat treating. I am mostly making sure that the hickory limbs are dry enough to prevent set. One could say the "reverse set" was not taken properly. Anyhow it does prevent any string follow, as I started with a straight stave. If I want I can easily heat treat the bow again, this time properly to brown color, and that reflex, usually just 2 inches again, stays put. After "exploding" several bows over the years, I play safe, until the day I decide to push it for some kind of personal record, like 170 FPS. The day will come when I reassemble my shooting machine, a glorified draw board, with proper parts this time, one of these days.

[willie]

I do reflex the working limbs about 2 inches while heat-treating the belly. Usually about 1 inch is left after shooting it several dozen times.

perhaps your reflex loss has more to do with your heat treating method and not necessarily indicative of the limb being stress hard enough to create set.

 I can easily heat treat the bow again, this time properly to brown color, and that reflex, usually just 2 inches again, stays put.

If you notice gain in draw weight you might consider side tillering to get it back down.

also, piking makes a bow effectively thicker. Another way to get the width, length, thickness ratios more in line at your 30# draw.

[scp]

I do reflex the working limbs about 2 inches while heat-treating the belly. Usually about 1 inch is left after shooting it several dozen times.

perhaps your reflex loss has more to do with your heat treating method and not necessarily indicative of the limb being stress hard enough to create set.

 I can easily heat treat the bow again, this time properly to brown color, and that reflex, usually just 2 inches again, stays put.

If you notice gain in draw weight you might consider side tillering to get it back down.

also, piking makes a bow effectively thicker. Another way to get the width, length, thickness ratios more in line at your 30# draw.

Thanks. All good ideas.
For now I leave them alone as I don't mind them to be overbuilt, too strong, or whatever, so long as they shoot acceptably. I will start tuning them for testing later. I just keep on shooting them occasionally as they are, noting what I can do with them if necessary. It's high time for me to start writing these options down. BTW I do pull up to 45 lbs. if the bow came out that way.

[mmattockx]

he is also looking for an optimum distribution of mass along the limb for his flight bows.

is this another way of asking how much a "stiff" tip can bend, and still be effective as a lever?

I don't think so. Arvin was making almost exclusively pyramid profile bows but he was searching for an optimization of how much weight to have in the inner/mid/outer limbs. He had put a lot of effort into it (to the point of cutting up successful bows to weigh the parts up and keep records on it all) but I was not really useful for that as it involves some limb dynamics that the software we have isn't capable of analyzing.

On the stiff tips question, I can say it is more than I would have guessed. Badger has told me that his super narrow lever style flight bows used a lever that was only ~30% thicker than the working portion of the limb, which leaves quite a bit of flex possible with the length and width of the levers involved. Can't argue with the results, though.


Mark