Primitive Archer
Main Discussion Area => Bows => Topic started by: Comancheria on December 09, 2014, 12:44:23 pm
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Bow questions:
I am working on this first bow and am nearing the point of putting it on the long string for tillering. I know that a tillering tree would be best, but right now, I have only a tillering stick and NO scale.
The bow will be unbacked and 70" long, NTN, is from a 72" red oak board with a handle 3/4" thick and the rest of the bow, right now, at about a uniform 5/8 inch. The handle is 7" long from where one fade levels off with the belly--to the same spot on the other limb. It is a pyramid, tapering from 1.5" wide at the fades to .5" at the tips. I am hoping for around 50# @ 28", but right now am going to let the bow end up tillered and worry about pull later.
First question relates to calibrating and reading the tillering stick. When I tell people so many inches of draw, I want to describe things the way other people on this forum do. The bottom of the yoke is exactly 3 inches from the first string slot. How do I label that slot? 1 inch? 3 inches? Do folks on this board typically refer to AMO draw length or to True draw length?
Second question: not certain where I saw it, but I have read that I should round off the edges of the back of the bow, to a radius about that of a pea--do you folks agree with that?
Third question: Right now, I have only a fast-flight long tillering string from 3-Rivers--2'with what looks like a standard loop on one end and the other end intended for a timber hitch. I am not ready yet to build my own string. So would it be safe to continue to use this FF string as the final bow string--at full draw--for shooting, until I can order a Dacron string of proper length?
I apologize for the length of this post but wanted to keep down the number of threads as I pose my many questions. My thanks.
Russ
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The back of your bow, to the crotch of your nock is draw length.
however your tree is set up, or a deep stiff handle compared to a thinner
bendy handle will change that length, so I use a small block for me bendy handles when I want an accurate draw length/weight measurement.
Yes, all edges should be rounded to prevent splinters.
that string should be fine, but I really think string making should be in conjunction with bow making. Once you learn its like tieing a shoe, and much cheapet and quicker than ordering online
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I second the string making - bite the bullet and learn it. My brother-in-law didn't learn and ended up using some fishing line, which was stretchy and awful. Don't be like my brother in law. The two of us spent the day after thanksgiving making strings for his bows, my nephews bow, and my bows- it was a heck of a lot of fun.
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It's easy to do. Can be a little tough on arthritic hands. Do a google search on "Flemish Twist". A $40 roll of string will make all the strings you need. And you can do it in your recliner ;D ;D
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Thanks, Wizardgoat, for answering my questions.
And guys, I thank you for your encouragement with regard to string making, and I assure you I fully intend to twist my own--eventually outbid sinew. But right now I don't want to delay final tillering and shooting while ordering materials and learning the process.
I also will end up making my own arrows, and have cane and Youpon drying in the garage--but for this first effort, this self bow--if it survives tillering--will be launching Gold Tip carbon! Thanks again for the help and encouragement.
Best regards,
Russ
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Russ, a tiller tree is as simple as nailing a piece of 2x4 to a post(for the bow to rest on) and adding a pulley about 4' below that, and a piece of rope. I like standing about 6' away from the tiller tree so about 10' of 1/4" nylon rope should get you there.
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Also, for a scale- I just use a fishing scale tied to the string I'm pulling. Only works for lighter weight bows, as the thing tops out at 50lbs.
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Sam's got some great string building info on his site.
http://poorfolkbows.com/
For the long string I just use sash cord.
My site has some info and buildalongs.
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
I also recommend a rope and pulley.
Jawge
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The bow will be unbacked and 70" long, NTN, is from a 72" red oak board with a handle 3/4" thick and the rest of the bow, right now, at about a uniform 5/8 inch. The handle is 7" long from where one fade levels off with the belly--to the same spot on the other limb. It is a pyramid, tapering from 1.5" wide at the fades to .5" at the tips. I am hoping for around 50# @ 28"
(...)
This is a perfectly fine lay-out. But you should be warned that there has to be some thickness taper. A pyramid bow starting at 1½" wide will not result in an even thickness throughout the limbs. Taper the limbs about 1/8" to start with. So 7/8" at the handle, tapering evenly to 5/8" tips. Proceed tillering from there.
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Your thinking TOO much, :laugh: just relax and take your time, don't work on it when you're in a rush or a bad mood, bad things happen then, now I'm gonna disagree with darksoul, get the limbs floor tillered to where they bend several inches, start with a even taper like you have, by the time your finished tillering you will have a slight thickness taper the length of the limbs but I always start with a even taper, good luck brother ask lots of?,'s when you need to and have fun
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Yes I agree that all sharp edges should be well rounded and the back sanded smooth! I start with 120 grit plumbers sand cloth working it like a shoe polishing then 180 grit to smooth out any saw marks.then I wet the back with a cloth let dry and 180 again then 0000 steel wool until I'm happy.preparing a boards back prior to tiller is key !IMHO.in short the back should be 95 percent done before starting.then a good floor tiller is in order(a very useful skill indeed)!if done correctly your bow will be 95 percent tillered before you start!anyways that what works for me.good luck!
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sometimes I tie a board to a post to make a portable tiller tree,, I use the pulley , I tie it on as well,, then I can move it anywhere there is a post,, I use a wooden yard stick tied to the board to measure draw,,,remember to start measuring from the back of the bow,, not the belly
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Pat: I hear you. After the first of the year, I am planning to construct a tree with either a four or six inch grid behind it, with the grid sheet able to be disassembled since there is not adequate room in the shop (er, the garage).
Jackson: I will be including a 100 pound scale as part of the setup. I had a beautiful 100 pound Chatillon that I bought for testing fishing line and knots for tuna fishing, but it was broken and cannot be repaired.
George: I have looked at Sam's site several times but good to know it deals with strings. When I get to doing strings, I will look there and on your site. Thank you.
Dark soul, Bushboy, and Bubby: thanks for your somewhat varied opinions. Actually, I think you are all in agreement on the most important point--that some taper will have to happen--at whatever point. And I do realize that. The bow bends a little on the floor right now--but just enough to see that it bends more near the handle and is going to require some taper.
Thanks,
Russ
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Russ
My backboard is 2'x 7' and is held to the post with a single 1/2" dia lag bolt. That allows me to rotate it so it's 2" wide and out of the way.
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Russ, when you get your bow to full brace measure the string length from the outer edge of each loop and let me know. I'll twist you up a double loop string.
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http://www.primitivearcher.com/smf/index.php/topic,35312.0.html
this is how I do a lot of pyramid board bows
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Thanks, DC. Good info. When the time comes, I will
Give that a try.
Clint, what a nice offer. I will accept gladly on this first bow. I hit a snag (quite literally) tonight when I noticed for the first time that one tip has a large chunk come out of the SIDE--must have happened when I was taking wood off the belly near that tip to work in some thickness taper. So I have one tip at a little over 1/2 inch wide, and the other right at 5/16. I will look it over tomorrow and before cutting in the nocks, I may have to shorten the tips about an inch and a half each, bringing the NTN length down from 70 " to more like 67 or 68 inches. May be a while before I get it to brace height (I am thinking 5-6 inches? I am working at the speed of a mole in solid granite! I will
Let you know, and thanks again.
Ah, the trials and tribulations of a master bowyer. 😄
Russ
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Bubby,
Thanks. That is looks like a great build-along. I actually followed a very similar procedure, though I wish I had taken a look at your build-along first. Lacking a band saw, I used a hand saw in to my width lines every inch or so, then chiseled out the material. The main difference between your bow and mine is that I have not--yet at least--glued on any additional handle material. May regret that if I decide to later on, given that I have already cut in the fades with just the 3/4" thick handle.
Russ
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The bow will be unbacked and 70" long, NTN, is from a 72" red oak board with a handle 3/4" thick and the rest of the bow, right now, at about a uniform 5/8 inch. The handle is 7" long from where one fade levels off with the belly--to the same spot on the other limb. It is a pyramid, tapering from 1.5" wide at the fades to .5" at the tips. I am hoping for around 50# @ 28"
(...)
This is a perfectly fine lay-out. But you should be warned that there has to be some thickness taper. A pyramid bow starting at 1½" wide will not result in an even thickness throughout the limbs. Taper the limbs about 1/8" to start with. So 7/8" at the handle, tapering evenly to 5/8" tips. Proceed tillering from there.
Dark Soul, you have prescribed 1/4" of taper, not 1/8". That's WAY too much for a pyramid style bow. If laid out as described in the thread about tillering from the edges, no thickness taper is needed. BUT, laid out as proposed in this thread some taper in the mid-to-tip area is needed. But certainly not 1/4", which would result in a decided whip tiller.
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You don't need to glue a piece on 3/4 is thick enough, you can build it up with cork or leather or rawhide to fill your hand, go ahead and cut it down you have plenty of wood
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3/4 inch thick handle...70 ntn - I don't think so.
I would make your handle 1 inch thick now. Better to have and not need.
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Dark Soul, you have prescribed 1/4" of taper, not 1/8". That's WAY too much for a pyramid style bow. If laid out as described in the thread about tillering from the edges, no thickness taper is needed. BUT, laid out as proposed in this thread some taper in the mid-to-tip area is needed. But certainly not 1/4", which would result in a decided whip tiller.
Whoops! You're right! :D Stupid emperial system... I actually meant 1/8" thickness taper, from 7/8" to 3/4" preferably. If the board was only 3/4" thick to begin with, then taper from 3/4" at the handle to 5/8" at the tips. Remember to not narrow the handle as you go, but to leave it full width.
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3/4 inch thick handle...70 ntn - I don't think so.
I would make your handle 1 inch thick now. Better to have and not need
Yeah mike 3/4" thick not wide, he already stated he's going to pike it to 67-68", plenty thick plus if it does flex a tad it won't hurt anything I bet the limbs at the fades are around 1/2" thick when finished
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Bubby,
(As a side note, every time I type in "Bubby", the iPhone tries to substitute "bunny"! 😳)
I am glad to hear your opinion as to the thickness of handle. Right now, at a more-or-less uniform 5/8 inch, the stave is still fairly stiff against the floor, so you may well be right about the near-handle thickness having to drop to 1/2". Right now, As might be expected, most of the bend is in that area, so my current plans are to try to work in some taper, starting by removing wood from the belly, mid limb, and seeing how that looks. Actually, it would not hurt my feelings if this first bow came in fairly light. 50 would be great, but I am a little leery of not having started with a wider board--say 2 inches instead of 1 1/2--and now having to shorten the bow somewhat.
Russ
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With that width shortening it will help you reach you're draw weight with less mass, I was texting a buddy about my little duck decoy, you can guess what the phone changed that too :laugh:
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I can only imagine!😊
Hmmm, maybe I ought to try narrowing the width of the wider tip and stay with 70 inches as a first try?
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Most of us are refering to tip movement, not the notch numbers, and that will vary with the long string length. I like to tie the long string as tight as I can w/o bending the bow.
Also, without a scale, get a weight of some sort, equal to what you want the final draw weight to be. Old dumbell plates, or a bucket of rocks, etc.. When you go to make a correction, hang the bucket on the string, either freehanding it, or actually hang it on the string while the bow sits on the cradle. Watch the tips move. If they move 3", take it off the bucket, and pull the string until the tips move 3", and NO FARTHER until you make a correction.
This method of never pulling the bow beyond desired draw weight has GREATLY increased my success rate. These days, if I get a bow roughed out without screwing up, I usually finish it.
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Thanks, Springbuck. Sounds like a good alternative.
OK, progress, but not sure how much. Sorry I still cannot post pictures yet. I went ahead and kept the length at 70", thinned both tips down to 1/2" wide. I cut nocks in and installed a string with timber hitch at the bottom, just able to have the loop slip over the top and hang loose. I exercised the limbs repeatedly down to 10, 11, 12...and eventually to 15 inches. I pulled weight on a bathroom scale which showed 21 pounds at 15 inch draw with the loose string.
Not sure how to proceed and am open to advice--(understanding as I do that this is difficult without pictures). The bow bends a little in the handle and near handle area. It bends somewhat less at mid-limb and not at all in the last 10 inches. To my imexperienced eye, the limbs are bending equally and both curve smoothly, and without visible hinges at this point.
I am wondering what the likely weight would be at 28 inches given 21# @ 15". Any guesses? (I promise not to sue!😀)
I am a little uncertain whether to remove more wood at this point at mid limb and within a few inches of the tip--OR--go ahead and keep exercising the limbs and pulling down further and checking tiller as I go.
I may have screwed up by cutting the nocks not only diagonally, but across the BACK of the tip. Does that constitute violation of the back? (Remember that this is a board bow not following one ring anyway).
Also, the knotted end of the string holds on quite well to the nock channels but the loop end hangs onto the back, but comes out of the side channels on top. Do I need to re-file these at a different angle or is the string likely to change direction
Imto the channels as the draw increases?
Thanks,
Russ
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almost impossible without pics to help with tillering, you can make a simple tillering gizmo with a 6" block and run a sheet rock screw in so the tip sticks out just a little, hold it against the limbs belly and find the spot with the biggest gap and run the screw out till it almost touches there, now run it back and forth the length of the limb it will scratch where you need to remove wood, scrape the wood of where the scratches are, exercise the limbs 20 times , repeat
as far as draw weight figure 3# an inch but don't worry much about that till you get to low brace
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Thanks, Bubby. Understood with regard to tillering. And with all my reading, I had not heard of that gizmo. May give it a try.
If the formula you suggests holds in this case, I would theoretically end up at 60 pounds. Sounds about right for the amount of wood I still have left on the belly.
Let me ask you (and anyone else for that matter), this: assuming I am correct that tiller is equal and smooth, does it appear safe for the bow at this point to keep drawing down and visually checking for hinges, or differential tiller? (Hope that question ales sense.)
Russ
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it sounds like it's bending to much in the handle/fades area, get the limbs bending in a even arc with that tool before you go farther
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Will do, and sorry to put you on the spot with no pictures. Can't say how much I appreciate the guidance--of you and others.
Russ
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Yeah, don't exercise the bow until you like the tiller, but you are way under your target at 21 lbs/15" If you can pull it 15", fer heck sakes, get that long string off it and get a real string on! The long string is only for the first few inches.
If you want a 40 lb b ow, just don't pull it more than either: enough bend to see what needs correction, OR more than final draw weight.
It sounds like it is bending all at the inner limbs. You need to spread the strain as much as possible. If it bends mostly at the inner limb, and not the midlimb, it will take set at the inner limb. That is the worst place to have set, because a little there affects the tips a lot. So, leave the inner limbs alone, and chase that inner limb bend out along the limbs to the middle section. The only place you want stiffness is the tips, maybe a thumb to pinkie spread length on a 70" bow.
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Here is how to make a proper tillering gizmo, the pencil marks much better than a metal screw.
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001047;p=0#000000
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Sorry--did not see the replies on this before posting the new thread describing the disaster. As Bubby said--and you empjasized, Sprimgbuck--that is exactly what happened. Lesson learned!
And thanks, Eric.
Russ