Primitive Archer
Main Discussion Area => Bows => Topic started by: Zugul on November 16, 2023, 08:33:27 am
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Hi guys, it's been a long time since I posted on the forum. in the last weeks I've had a bit of free time so I started a new bow, but I think I messed up the design. I've already taken down the stave to this dimensions: 63" long (it was pretty short from the start), 1 1/3" wide in the 4" handle section and from there a straight taper to 1/2" tips. Wood is black locust. My idea was to make a bendy handle flat bow using the faceted tillering method, 35-40# at 28" of draw. Is it a decent design or the very narrow limbs will probably fret? (--)
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Sounds quite narrow but possible for a good piece of wood with perfect tiller.
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I'd bet they'd fret.
Only one way to find out.
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The length is fine for a 28" draw but the width is a bit narrow for locust. Bending through the handle will help it out and you can heat treat locust and that should help also but it will still take good tillering and easing through the process.
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For sure it can be done if you let every part of the bow do some work (except for stiffer tips).
Good tiller from the start as well correct WIDTH taper of the bow
(often reason why white wood bows fret) is essential.
Let us know how it´s going :)
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Just to give you some encouragement.
This bow is from a Norway maple sapling- Acer platanoides. I´m not sure how it compares with locust but still... I think it is far from doomed!
It´s 1,3" wide,
64" ntn
#50 at 27" (It´s been tested to 28")
And holds a reflex of 1,5"
slightly rounded back and flat belly. Bends in handle
Excuse the bad pictures but you get an idea.
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I like to keep the middle 1/3 parallel and taper the outers. That said I have done 1.25" wide with that layout and been successful for 50 lb locust bows. I never tried to taper the whole limb(s) but at 40 lb draw i think you have a good enough chance to give it a go. I'd keep the nocks short to get 62" ntn, heat treat, and at about 20 inches on the tiller trap the back 1/8" inch on each side. It ought to have a real good cast with your design. Hope to see this piece all finished up. good luck!
Mike
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Is it a decent design or the very narrow limbs will probably fret?
decent design (length and width ) is fine, as it is similar to many primitive bows
will your stave make your weight goal without fretting is a slightly different question.
if you find the bow starting to take set early, you might lower your weight goal.
trace an outline of the back on a piece of cardboard before starting tillering. with this you can
watch for tempory set upon unstringing and monitor tempory set recovery rates
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thanks everyone for your insight, I'll post some pics in the next days and then move forward. I'm a little more confident now, but I'll make sure to go on very slowly and carefully.
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I think your pushing limits for sure. I’m interested to find out about the even diminishing though. Being a bend in the handle bow it might make it. Black locust is pretty dense. Should turn out about 5/8 thick I’m guessing.40# seems reasonable.
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So, here are a few pics of the stave I'm working with.
(https://live.staticflickr.com/65535/53343446945_e3d2308b44_b.jpg) (https://flic.kr/p/2pgM7jv)
The stave is not straight but since it's not very wide i think it won't be very hard to correct it with dry heat and some oil
(https://live.staticflickr.com/65535/53342108537_c7c19f9517_b.jpg) (https://flic.kr/p/2pgEfsv)
Early to late wood ratio does not seem that bad, but this end has already been thinned. Just under that section there is one with thin rings and 1:1 early to late wood ratio, wich probably will not get removed during tillering in the mid section of the bow.
(https://live.staticflickr.com/65535/53342996116_4464bcc306_b.jpg) (https://flic.kr/p/2pgJNiA)
This feature is a cluster of pin knots, just above mid limb. I've left quite a bit of wood around it but it's pretty prominent and I think I should leave it stiffer then the rest of the limb to prevent if from failing in tension.
How bad do you think the situation is now? (--)
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I like it. Looks like you’ve done well with those knots. As long as you go slow and keep the bend even during tillering, I’m optimistic!
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That knot makes it absolutely critical you make sure you distribute the bend evenly on an already short bow. But I think it can be done. Much up to you but also depends if the wood is good or of less good quality. Go slow and keep a bucket with ice water next to you to dunk your head in when you´re getting impatient.
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Today I spent an hour getting closer to initial tillering dimentions. As said in my first post on this thread I'd like to try the faceted tillering method, but since the bow will be very stressed I've opted for very narrow inclined facets, so the belly will be nearly flat and not very rounded, to distribute better the strain it will face. At this point the stave weight is 607 grams or 21.4 oz. My estimate is that it still holds around 12% moisture, so I'll move it to a drier spot of the house. Next time I'll work on it I'll round a bit the sharp corners and then search for thick spots with a caliper to make sure I have a nice thickness taper before starting to bend the bow.
Go slow and keep a bucket with ice water next to you to dunk your head in when you´re getting impatient.
This advice is crucial since impatience is my biggest enemy :-[
Of course any other advice is more then welcome, thanks for your time guys!
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I'm very slowly making heat corrections, the alignment is a lot better but still not super good, when I'll be satisfied I'll post some pics. I'm also thinking about taking away the natural reflex of the stave, to make the bow less stressed since it's pretty narrow and short. What do you guys think?
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When did the long crack happen on the knot. The wood is to wet. Let it set a couple weeks or so and wrap both sides of that knot with rawhide when you get the bow drawn to about 20” and close to target weight. Wrap it. And my 67” bows 40@28 is 24-26 #t 20”. 50@28 is 38-40@20. You can probably get any bow of that length an weigh it and get a reference on the 20” weight rule. This is where set happens for me . That will give you an idea so you can rawhide early.. just a suggestion. Good luck with the build.
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In your last pic posted you show the knot cluster. It looks to me in the pic that you have left enough meat around that knot but it looks like you may have some grain run out on the right side of it. My suggestion on this knot is to have little to no grain run off here. I would make every effort to strictly keep to the grain lines around this sucker. Even if it looks a little weird and you get the urge to narrow it intuitively to match the width of the other limb don’t do it. Leave it with equal measure of wood on both sides of this knot but keep to zero grain run at this location. You can always slowly and increments of narrowing up away from this cluster to get to where you want. I agree with what others have said here too with that it’s a shorter bow to achieve to draw length and weight you are looking for but it is doable. Especially if bendy thru handle bow. This means every part of this bow is working so that is also why it’s crucial that that knot is got no run off there. You basically want the wood around that knot to support the bend stresses alone and should be able to drill out that knot and still have it bend good. Not that I’m suggesting you drill it out but my point I’m trying to make is that you need to work that knot as if it it doing the work on it own and not relying on any help from that cluster. Anyway that’s my opinion of what I’d do with the knot. It would give some neat character too. As far as the twist I may just get it bending to about 20” first following all of the dips and valleys belly to back for good consistency of thickness. Use your finger calipers as bjorn says! I think your in good shape so long as you give attention to those crucial areas of potential problems areas. Get to 20” draw then maybe worry about any twist corrections. Imho best of luck on it.
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When did the long crack happen on the knot. The wood is to wet. Let it set a couple weeks or so and wrap both sides of that knot with rawhide when you get the bow drawn to about 20” and close to target weight. Wrap it. And my 67” bows 40@28 is 24-26 #t 20”. 50@28 is 38-40@20. You can probably get any bow of that length an weigh it and get a reference on the 20” weight rule. This is where set happens for me . That will give you an idea so you can rawhide early.. just a suggestion. Good luck with the build.
There are no cracks in that area, the dark line is simply a pencil line I drew to help me establish the centre of the limb lenght-wise. I've kept the stave in a spot where I normally measure 66-72°F and 40-50% RH until it stopped loosing weght (2 weeks ago) so I'm pretty confident it should have around 8-9% humidity left in it. Thanks for the references of draw weight - draw lenght, they will come in handy as soon as I start tillering!
In your last pic posted you show the knot cluster. It looks to me in the pic that you have left enough meat around that knot but it looks like you may have some grain run out on the right side of it. My suggestion on this knot is to have little to no grain run off here. I would make every effort to strictly keep to the grain lines around this sucker. Even if it looks a little weird and you get the urge to narrow it intuitively to match the width of the other limb don’t do it. Leave it with equal measure of wood on both sides of this knot but keep to zero grain run at this location. You can always slowly and increments of narrowing up away from this cluster to get to where you want. I agree with what others have said here too with that it’s a shorter bow to achieve to draw length and weight you are looking for but it is doable. Especially if bendy thru handle bow. This means every part of this bow is working so that is also why it’s crucial that that knot is got no run off there. You basically want the wood around that knot to support the bend stresses alone and should be able to drill out that knot and still have it bend good. Not that I’m suggesting you drill it out but my point I’m trying to make is that you need to work that knot as if it it doing the work on it own and not relying on any help from that cluster. Anyway that’s my opinion of what I’d do with the knot. It would give some neat character too. As far as the twist I may just get it bending to about 20” first following all of the dips and valleys belly to back for good consistency of thickness. Use your finger calipers as bjorn says! I think your in good shape so long as you give attention to those crucial areas of potential problems areas. Get to 20” draw then maybe worry about any twist corrections. Imho best of luck on it.
At the moment there is a bit of grain runoff on one side of the knot, the one where I've left a bit more wood. Should I keep it wider or thin it? From what I understand now about working around the knot, I should simply have the limb as wide as it should be by design in that spot plus the with of the knot itself, correct? About the alignment, I'm correcting it now because before I started the string line was laying about 1 1/2" outside the handle, so it would have been pretty much impossible to start flexing the bow without it twisting on the tillering tree.
thanks everyone for your advice, I'm pretty slow and full of insecurities when I learn something new! ;D
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here some pics of where I'm at now: the "bow" is pretty much straight now, the string line tracks just 1/4" off the centre line in the handle.
(https://live.staticflickr.com/65535/53411071869_e650058629_h.jpg) (https://flic.kr/p/2pnKGRt)
(https://live.staticflickr.com/65535/53410738341_5d9c3c7caf_h.jpg) (https://flic.kr/p/2pnHZGZ)
I'd say I can start removing wood in the next days, to make sure the thickness taper is even and also to let the stave rehydrate properly before starting the proper tillering process, going as slow as I can O:)
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No problem we are all learning here. Like others have already said. Take it slow. As for the wood around the knot I think your approach will work too but what I’ve done in the past is measure the width of the same spot along the other limb and equally split that width on both side of your big knot cluster. This depends too on the condition of your knots too. If solid and not just punky dead cluster of knots then doing this way errors on side of caution. Your approach is similar. As far as your twist I see what your saying. I would do the same if it was off this much.
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just a question, where do you normally measure the width of a knot? because this one is very small on the belly side (1/4") but becomes a lot bigger on the back of the stave ( 3/4"). So if I leave the right amount of wood around it on the belly I'm pretty narrow on the back, the other way around if I follow the width on the back I'm probably over compensating on the belly. I hope I explained it properly :P
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The back. You need the extra width to protect the back. The extra wood on the belly will simply be made thinner so it will bend.
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looking good so far. 1/4 off center should work well for you. I always try and keep string alignment closer to arrow pass side. you could even cheat the nocks over to get a little closer depending on what you want, still need arrows spined well. If you follow the grain around that knot it should give you the width of good material you need(maybe too simple of a statement....) draw with a pencil first and have a look and measure, but I like what Slimbob advice is. Good luck!
Mike
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so, after a very long time I've started working again on this bow. First of all I took off the string nocks I made, since I could not make the tillering string stay in place securely. I've opted for simple wood tip overlays instead, wich I'll leave roughed out until the bow is pretty much complete. After that I sanded down all corners and I used a caliper to make sure there were no thick spots on the limbs. Lastly I used a straight edge to mark a line on one side of the bow, from the center out to both tips. This way I can see better what areas are bending more then the others, simply watching how the line is bending. Here is where i'm at now, 35# at 3". All advice are welcome!
(https://live.staticflickr.com/65535/53808611220_648ebc7015_h.jpg) (https://flic.kr/p/2pYTcsd)
3" draw lenght, I've added the straight green lines to make it easier to see the bend.
(https://live.staticflickr.com/65535/53808174361_a6a6eba36b_h.jpg) (https://flic.kr/p/2pYQXAa)
if you click on the pictures you can see them on flickr and there you can zoom on them to see the line better ;)
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Following this thread. Best of luck to you with it!!
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Be careful with the outer half on left limb - between the nock and the knot. Could be an illusion but it looks like its the weakest there. Reduce weight elsewhere especially on right limb.
Risk is you leave the knot too stiff and that it cases frets elsewhere when the wood tries to compensate..
go slow and enjoy!
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I agree, it seems week there... but the line is not bending that much more then anywhere else. I'll leave that spot alone for now. I'll thin a bit where the knot is, very carefully since that could easily become a weak spot if I don't go slow enough.
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so, I made a little bit of progress on this bow. I'm pretty sure I was drawing a bit over my target weight in the pictures above, since after at least 60 scrapes with a card scraper on the entire bow I'm still al 35# at 3"... Luckily the stave didn't take any set and didn't fret, so I'm positive about it managing to hit target weight if I do my part correctly. Now the measurements are:
max thickness: 21 mm (53/64"), middle point of the bow
min thickness: 14 mm (9/16"), 4" from each end of the bow (I've decided to leave only the last 4" of each limb stiff, to gain a little more draw lenght)
phisical weight: 526 g (18 1/2 oz.)
from what I understand at the end the max and min thicknesses should be around 3/4" (19 mm) and 1/2" (13 mm), so from now on the weight should drop pretty fast.
As always, if I say something wrong feel free to correct me, since I'm here to learn ;)
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looking good. keep us posted.
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making very slow progress, I'm at 35# at 4". I'd say it's bending pretty evenly, but I'll wait for advice from someone more experienced.
click on the pictures to see them on flickr if you want to zoom on them
(https://live.staticflickr.com/65535/53832831034_40b75c69fa_o.jpg) (https://flic.kr/p/2q22kad)
(https://live.staticflickr.com/65535/53832927765_d54e8689dc_o.jpg) (https://flic.kr/p/2q22PUZ)
(https://live.staticflickr.com/65535/53832831039_008c3f2f3c_o.jpg) (https://flic.kr/p/2q22kai)
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I've gained 1 1/2 inches of draw and to me it seems like the inner half of both limbs is bending decently while the outher half is pretty stiff (left outer 1/2 limb stiffer then the right one). What do you guys think?
(https://live.staticflickr.com/65535/53917984021_db6873f41a_k.jpg) (https://flic.kr/p/2q9xLba)
(https://live.staticflickr.com/65535/53918336259_022cb9f585_k.jpg) (https://flic.kr/p/2q9zyTe)
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After a long pause I got at this bow again, now it's finally at low brace height. I also corrected the deflex between the knot and the end of the left limb, to make it easier to judge the bend there. To my eye the bow seems a bit stiff in the inner 1/3 of each limb and in the knot area, what do you guys think?
(https://live.staticflickr.com/65535/54118884070_5a723bf548_k.jpg) (https://flic.kr/p/2qsiqL7)
(https://live.staticflickr.com/65535/54118757384_d2e6a16cdb_k.jpg) (https://flic.kr/p/2qshM6S)
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Yup that’s what I see too. Looking good though. Get it to brace and then get better idea on how the bend is coming from brace. The bend draw will look different from brace.
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Finally managed to get the bow to a 5" brace height, after getting it to 35# at a little more then 14" when it was at a shorter brace. It started getting a bit of set (1/2") pretty spread out along both limbs but there's a touch more of it at the wiggle on the right of the middle of the bow, so that area wil stay untouched. Other than that I'd say it can bend a touch more right in the middle, thoughts? After that adjustment I'd just keep getting the weight down while I approach draw lenght :BB
(https://live.staticflickr.com/65535/54155166961_cf1a20991b_k.jpg) (https://flic.kr/p/2qvvopc)
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I did a few little tweaks and brought the brace height up to 6", the weight is now at 35# at 16". Set did not increase so it seems like I'm on the right track, maybe the right limb is still a bit stiff around mid limb. From now it should be only a matter of adjusting the right limb and then even mass removal and frequent tiller checks, correct?
If you click on the image you'll be sent to the one I posted on flickr, where you can zoom on it if needed to better judge the bend
(https://live.staticflickr.com/65535/54161290425_5c3b610e65_k.jpg) (https://flic.kr/p/2qw3LGa)
(https://live.staticflickr.com/65535/54160977911_3fd3c271d5_k.jpg) (https://flic.kr/p/2qw2aMZ)
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Looking really good to my eyes. Pappy
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Me too
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So, I've tillered this bow a bit more, now it's 35# at around 19.5" of draw lenght. I tried something new to see if I'm on the right track: I've made a realistic model of my bow (for what I could) on VirtualBow and then I "tillered" the virtual version to get an even distribution of stress across the bow, maintaining the front profile and changing only the thickness of the limbs. My reasoning is that, for a ceartain front profile, there's only one particular shape (tiller) the bow can have to spread the load evenly across the limbs, wich should minimize set. Feel free to correct me if I'm wrong, I still consider myself a complete newbie! :BB Here are pictures of the bow and the model from VirtualBow at the same brace height and draw lenght.
(https://live.staticflickr.com/65535/54302949208_7728d2858b_k.jpg) (https://flic.kr/p/2qJyNUY)
(https://live.staticflickr.com/65535/54302699151_91c4a88079_k.jpg) (https://flic.kr/p/2qJxwzD)
(https://live.staticflickr.com/65535/54302938779_cade83d816_h.jpg) (https://flic.kr/p/2qJyKPa)
(https://live.staticflickr.com/65535/54303132000_8636a7b84d_k.jpg) (https://flic.kr/p/2qJzKfy)
(https://live.staticflickr.com/65535/54302961649_d2720dbb0c_b.jpg) (https://flic.kr/p/2qJySBt)
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Still looking really good to me. :)
Pappy
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Whatever you are doing it looks really good to me so far and it seems like your unbraced profile is holding its shape well.
Bjrogg
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So, I've tillered this bow a bit more, now it's 35# at around 19.5" of draw lenght. I tried something new to see if I'm on the right track: I've made a realistic model of my bow (for what I could) on VirtualBow and then I "tillered" the virtual version to get an even distribution of stress across the bow, maintaining the front profile and changing only the thickness of the limbs. My reasoning is that, for a ceartain front profile, there's only one particular shape (tiller) the bow can have to spread the load evenly across the limbs, wich should minimize set. Feel free to correct me if I'm wrong, I still consider myself a complete newbie! :BB Here are pictures of the bow and the model from VirtualBow at the same brace height and draw lenght.
(https://live.staticflickr.com/65535/54302949208_7728d2858b_k.jpg) (https://flic.kr/p/2qJyNUY)
(https://live.staticflickr.com/65535/54302699151_91c4a88079_k.jpg) (https://flic.kr/p/2qJxwzD)
(https://live.staticflickr.com/65535/54302938779_cade83d816_h.jpg) (https://flic.kr/p/2qJyKPa)
(https://live.staticflickr.com/65535/54303132000_8636a7b84d_k.jpg) (https://flic.kr/p/2qJzKfy)
(https://live.staticflickr.com/65535/54302961649_d2720dbb0c_b.jpg) (https://flic.kr/p/2qJySBt)
Glad to see you back and still working on this bow. I think it has real potentional to be a bow that works for you!
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Whatever you are doing it looks really good to me so far and it seems like your unbraced profile is holding its shape well.
Bjrogg
agreed, and looks like you have that knot area neither to stiff or weak which can be tricky
for a ceartain front profile, there's only one particular shape (tiller) the bow can have to spread the load evenly across the limbs, wich should minimize set.
very true. and the best approach since you are concerned with getting 40# out of a short and narrow stave.
when width and length allow, having a stiffer (lesser stressed) handle area and tips can improve performance and feel (dampness) in the hand.
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Still looking really good to me. :)
Pappy
thaks, it's really heartening to hear it!
Whatever you are doing it looks really good to me so far and it seems like your unbraced profile is holding its shape well.
Bjrogg
It did take a bit of set, around 1/2" for now, but I'm fine with it considering the sub-optimal design I chose
Glad to see you back and still working on this bow. I think it has real potentional to be a bow that works for you!
Thanks! I hope this piece of wood thinks the same! ;D
Whatever you are doing it looks really good to me so far and it seems like your unbraced profile is holding its shape well.
Bjrogg
agreed, and looks like you have that knot area neither to stiff or weak which can be tricky
for a ceartain front profile, there's only one particular shape (tiller) the bow can have to spread the load evenly across the limbs, wich should minimize set.
very true. and the best approach since you are concerned with getting 40# out of a short and narrow stave.
when width and length allow, having a stiffer (lesser stressed) handle area and tips can improve performance and feel (dampness) in the hand.
I'd say the knot area is still a tad stiff, but I don't want to weaken it too much... I'll keep a close eye on it while tillering. Since a bit of set already happened I dropped my target weight to 35# and even if I come a couple of pounds uderweight I won't be mad as long as I get a functional bow. For my next project I already have a much longer and wider floor tillered stave waiting on wich I'll try to leave those areas stiffer.
I did not make any progress with the tillering process yet but I took off the tip overlays since they were made out of a not strong enough wood (Sorbus torminalis, wild service tree) wich was getting dough into by the string and made new ones from heat treated black locust, wich should be strong enough and should look good. I hope to finish up the tip overlays this afternoon and then get back at tillering in the weekend. Thanks to all of you for the kind replies!
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just a quick update on the tip overlays: I sanded smooth one of them up to 280 grit and then burnished half of it, this is the result. It's still unfinished but I'll get to it when the bow is complete.
(https://live.staticflickr.com/65535/54314754483_720b009aff_k.jpg) (https://flic.kr/p/2qKBjdc)
I think it looks pretty neat!
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little update: I got down to 35# @ 22".
precise measurements (since it seems I did not post them before):
handle section: 34 mm wide, 15 mm thick
end of the working limb: 17 mm wide, 10 mm thick
total mass of the bow (without string): 378 g ( 13.3 oz)
The bow is getting scarily thin and light, but it doesn't seem to have taken any more set. I've started running a caliper down the limbs every 20-30 scrapes to be sure I don't leave any thick spot and to check that I have the same thickness on both sides of each limb.
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sounds like you are getting there. At those low draw weights and thin limbs, a bow can take a good old bend before failing.
Mind they always wait unit that last inch of draw before exploding!
I think the caliper test is a good idea. Slow and steady in these final stages.
Del
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What a great build to follow along with! Keep at it!
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Thanks for posting this! It looks great! I'm starting into a black locust stave for my 2nd bow, and this is giving me hope and some ideas on how i want to go about it. Albeit mine is a skosh shorter.
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What a great build to follow along with! Keep at it!
Thanks, it's really nice to know I'm entertaining someone with this build!
Thanks for posting this! It looks great! I'm starting into a black locust stave for my 2nd bow, and this is giving me hope and some ideas on how i want to go about it. Albeit mine is a skosh shorter.
good to know, I hope to see you make a thread about it! Just my 2 cents, spend all the time you need to get a near perfect thickness taper from the start, even if it's not going to be the final one. Having absolutely no thick spots or weak ones will greatly improve your chances of success. Good luck!