As I had mentioned earlier in the forum, I think I have fairly successfully glued the horn to the limbs using shallow non-matching grooves, hide glue, and pressure pad clamping with multiple C-clamps. The glue line is very thin and even, and I think I have a good bonding.
I am now at the point where I am in the process of thinning out both the core and horn, and so far it seems to be going well. I want to make sure I don't remove too much or too little material before I apply the sinew.
I would like this bow to have a draw weight of about 55 - 60 lbs. It's a typical Magyar bow configuration. In the unbraced position the straight-line nock to nock distance is about 123 cm. The limbs are positioned 10 degrees from the horizontal and the ears angle about 30 degrees from the limbs. The bending section of the limb is a little less than 30 cm long.
Right now, the bending section is about 36 mm wide where it starts near the grip, 33 mm in the middle, and 29 mm at the eye of V-splice of the ear. At present, the actual horn layer is about 1 mm narrower than this. The combined thickness of the horn plus core is about 12.5 - 13 mm near the fade, 11 mm in the middle, and 11.5 mm near the ear. The thickness of the horn varies from about 6 mm down to 5 mm, so right now most of the wood core is about 6.5 to 5.5 mm thick. The edges have been rounded to give a very slightly elliptical cross-section.
At these dimensions the limbs still feel rather stiff. For example, if I clamp on of the limbs down on my workbench and hang a 10-pound weight on the nock of the opposite limb (equivalent to 20 lbs on both limbs) the nock only moves down about 9.3 cm. Assuming the draw is linear, 30 lbs on one limb would move the nock down roughly 27 -28 cm. And this is without any sinew. (I am afraid to do anymore draw testing without the sinew on.) After a 2 -3 mm layer of sinew is applied, the limbs will be even more stiff, but I don't have a feel for how much more.
This is my first horn bow, so I don't have a good feel for how much draw weight one will get at various thicknesses, or how much stiffer the limbs will be after the sinew goes. So, to get a bow approaching 60 lbs draw weight at 26 inches, I'd like some advice with regard to how much more wood and horn removal I should do, if any. I realize one can't predict these things exactly, but I want to be sure that the final bow will be somewhere in the neighborhood of 60 lbs.
Some related questions:
Should I leave the horn alone (except for beveling the edges a bit more) and only remove the remaining material from the wood core?
What should the final thickness of the horn plus core be at start, middle, and end of the bending section?
Should I remove more wood from the width so that the wood does not overlap the horn at all? I want to be very cautious about this, because once the sinew goes on, I obviously can't remove any more wood from the core.
What sinew thickness is advisable?
Thanks to all in advance for any advice you might offer.
paku
The horn should taper from 5-6 to 2-3mm do not touch it now.
For the first bow it is best to go with 4-4-4mm for the layers. For a 130cm ntn bow, (with 35mm) these dimensions will result a bow about 60 pounds.
You can leave the wood wider than the horn the sinew you will cover this area.
fusizoli
How long is the bow, mesured along the back or belly betwen the nocks? A soft scale help to mesure it.
A longer bow needs more thicknes than a shorter one for the same draw weight.
Edmund Dohnert
Paku and Zolt?n -
Thank you both for getting back.
As measured along the belly of the bow , the nock-to-nock distance of the unbraced bow is a little less than 136 cm.
Regarding the maximum leverage on the bending section, the horizontal distance from the nock to the what I consider to be the start of the bending section is approx. 53 cm.
Do I understand correctly that I should wait till the sinew is all on and properly cured before I do any more material removal on the horn layer?
However, I do need to get wood core to its correct final thickness before the sinew goes on. Should I bring the core down to a uniform thickness of 4 mm along the entire bending section? Or should there still be some minor thickness tapering of the core?
If I make the wood core 4 mm thick along the entire length of the bending section, right now, with the horn being 6 to 5 mm thick, the total thickness of the bending section (without sinew) would be 10 to 9 mm thick. Should I go with this thickness and then start sinewing?
I haven't acquired any sinew yet and haven't done it before. If I apply a 3 - 4 mm thick sinew layer, roughly how many pieces of deer leg sinew of typical size would I need? What about the more expensive deer or elk backstrap sinew? Are they better?
Tc
1. Yes, do not touch the horn now. Leave it as thick as possible for the tillering procedure.
2. This is a large Magyar bow made by S?ndor Paku. (I hope he doesn?t mind sharing it here?Nem baj ugye, Sanyi b?csi (k)?) Properties are not exactly the same as yours, but could be a good starting point. The draw of the bow is with no sinew of course.. http://kakasi.eu/ijaszat/kep/paku-nagy-magyar-50-55.png
3. See answer 2.
4. Aprox. 12-18 large deer (or cow, horse) leg tendons should be enough, but it depends on the waste you produce during sinew processing..Backstrap sinew is good to use (the longer the better), the whole bending section of the limb can be covered without overlapping but that is the only advantage of it.
Making and using a Magyar horn bow is a nice experience, good luck! If you have further questions do not hesitate, we are all happy to help you!
fusizoli
On this picture the thicknes is the horn and wood core together!
As S?ndor sad, the horn schould taper from 5-6 at the gripp toward the the tip to 3mm. So the middle of the limb it will be about 4-4mm or a bit more.
As You can see the core is not uniform tapered.
At the end it doesn't need to be 5-6 mm horn. It is just dead weight.
Before start the sinewing process, have to taper the core and then round the corners (on the horn too). The horn schould be flat rounded.
Normally 3 layer of sinew enough. The glue have to be enough viscose for sinewing! Less than 20-25% makes trouble!
For the last layer I would prefer min 35cm or longer elk or other sinew.
Edmund Dohnert
Zolt?n and TC -
Thanks for the input.
That profile of Paku's bow showing thicknesses of the un-sinewed bow along its length was very helpful. While my bow is a little shorter, I don't think I'm very far off with regard to the shape. I just need to remove a little more wood from the core to get somewhat closer to the total limb thicknesses shown.
Tell me if I'm wrong, but I tend to think that if one wants to have a bow that is less likely to break, for a given total limb thickness it is better to have a horn layer that is slightly thicker than the wood layer. For example, if you want a total limb thickness (less sinew) of about 10 mm, then wouldn't it be better to have 6 mm of horn and 4 mm of wood, rather than 4 mm of horn and 6 mm of wood?
Or in other words, when most bows break, isn't it a failure of the wood core rather than the fault of the horn or sinew? If so, then I would think that it is best to keep the wood core as thin as is practical.
So, I am thinking about removing enough wood so that the core tapers from about 5 mm down to 4 mm. I will leave the horn as is until after all the sinew is applied.
I just ordered some elk backstrap sinew.
I just love this bow project, as I feel I am participating in some ancient long forgotten arts.
Thanks again.
paku
Keep in mind that thin wood core can make the bow unstable. It will be difficult to balance it.
fusizoli
Edmund
Got the PM ?
Edmund Dohnert
Paku + Zolt?n -
I recognize the importance of not letting the wooden core get too thin, as it appears that its most important function is to provide a stable spacer between the horn and sinew layers, which actually do most of the work.
I have left the horn alone for now but have removed some more wood from the core.
Here are the current total (horn + core) thicknesses as measured from the middle of the grip:
0 mm 36 mm
50 29
100 14
150 11.5
200 10.5
250 10
300 10
350 10
400 11
450 16 (includes part of ear)
At present, the thickness of horn layer varies from about 6 mm down to 4.5 mm. As you advised, I won't do any more removal from the horn until after the sinew is applied.
I think I am probably getting close to where I should be, so I want to be very careful. Do you think I should removed any more wood before sinewing, or should I leave it as is? As I said, I don't need this bow to have a draw weight greater than 60 lbs.
I've ordered some deer sinew and will probably be able to start sinewing within two weeks.
fusizoli
It still looking a monster and not a 60# bow core. :)
The finished bow with the 3 layer of sinew would be about 11mm at 30 from the center.
So the core there with the horn is not much more than 8mm! The sinew layer will be 3mm there and most of the bending part.
You have 2mm extra there.
Have to work down the thicknesses 0.1mm accuracy before sinewing!
Had PM the datas, could work after that.
Edmund Dohnert
Zolt?n,
Yes, I received all of your PMs. Thanks again. The one with the dimensions of Paku's 130 cm, 60-lb bow was most helpful.
I think I neglected to point out in my last post that the current dimensions of total thicknesses included an extra 1 mm that I was intending to remove from the horn layer after the sinew is on and I am in the tillering process. As such, you should really subtract 1 mm from all of my total thickness dimensions.
When you do that, my bow's horn + core layer would still be about an average of 1 to 1.2 mm thicker than Paku's, the ratio of my thickness to Paku's varying from 1.0 to 1.15. As the stiffness varies with the cube of the thickness, my bow, as is, will still be perhaps 25% or more stiffer than Paku's, or maybe something like 75 lbs of more, which is much more than I need or can handle.
Right now, my wood core thickness (from the point 150 mm to 350 mm from the center of the grip) varies from about 6.0 to 4.5 mm. Paku's core thickness at those same distances varies from 5.8 to 4.7. Therefore, with regard to the wood, I am somewhat hesitant to remove much more. Or maybe I should?
If I understood Paku correctly, he suggested that I leave the horn layer alone until all the sinew is in place and I am ready for tillering. Do you do the same thing, or would you suggest I remove some more horn before the sinew goes on? As I said, I purposely left the horn about 1 mm thicker that it's probable final dimensions.
fusizoli
Have to make the with taper too, mesure from the centerline and round the edge of the horn and core.
The sinew will cover the edge of the horn on the belly side, like on cross section horbow pics. So the horn would be rounded a bit and taper near the corners.
Here is some pics on my photobucket, not so much but may it helps. http://s1212.photobucket.com/user/fusiz ... ort=3&o=15
mikekeswick
When Paku said don't touch the horn I think he may have neant don't touch the overall thickness but the profile should be rounded before sinewing.
Have you formed the width taper?
Have you rounded the belly yet?
A photo of your progress so far would be useful.
Also I strongly suggest getting some calipers to measure the widths/thicknesses accurately, especially for your first few bows. I used rulers to begin with and they leave a bit to be desired!
fusizoli
Agree with Mike!
Edmund Dohnert
Mikekeswick -
Those thickness measurements were made with a caliper (albeit a fairly simple one).
I have tapered the limbs, but I suppose there is still some room for additional taper. Right now, the width is as follows, as measured at the indicated distance from the center of the grip:
100 mm 36 mm
250 mm 34 mm
400 mm 29 mm (this being almost at the start of the point of ear splice, there being some additional taper along the remaining distance to the very end of the core).
What do you think: more width tapering or should this be sufficient?
I have rounded the edges of both the horn and the core, though it could probably use some more rounding before I am ready for sinewing.
I wish I could post a photo of the bow, but I live in the 9th Century and don't have a digital camera yet.
fusizoli
9-10 th century is the best period to make a magyar bow. :lol:
Mesure it from zero to every 5cm and send that list. :wink:
Edmund Dohnert
Zlot?n -
Provide below are the current width and thickness dimensions (in mm) of the limb (horn + core) measured at 50 mm increments from the center of the grip
0 29 35
50 32 30
100 36 13
150 35.5 11.5
200 35 10.5
250 34.5 10
300 33 10
350 31.5 9.5
400 29 10.5
450 26 17 (includes part of ear)
As I mentioned earlier, in most places from about 100 - 150 mm outward the horn is thicker than the wood, and I picture removing an additional 1 mm of horn prior to sinewing, which will reduce all of the above thickness dimensions by 1 mm.
I'm anxious for your advice regarding i) how much more horn (and possibly wood I should remove, and ii) whether I should increase the width tapering.
The grip feels a little thick, so I will probably remove some material from there. The edges could also be rounded some more.
mikekeswick
Sorry I don't have time for full reply but your widthsa appear ok at a glkance abut your thicknesses could do with a mm or so removing. Also as you say the grip is very thick but that comes down to personal preference.
fusizoli
The sinew layers will add about 4mm thickness on the gripp section.
Edmund Dohnert
Zolt?n + mikekeswick -
I will VERY carefully remove another 1 mm. As the horn is thicker than the wood except near the grip end of the bending section, most of this removal will be from the horn layer.
Thanks for reminding me that the sinew will make the grip even thicker than it is now. I definitely need to remove more material from the grip.
By the way, do either of you do some shallow grooving on the back of the core before applying sinew?
Tc
Yes, give the sinew something to grab... A metal saw blade is just perfect to do the job. And do not forget the sizing, 4-5 thin (2-5% glue) layers and a thicker one (15-20%) just before the sinewing should be fine..
Tc
One more thing... Normally the grip of Magyar bows is covered by either bone or horn plates and the plates are partially covered by sinew, so they are to be glued on before sinewing..It is a bit tricky to fix the plates on but they give a better protection to the bow during shooting than sinew. There is a photo in Zoltan's gallery showing use of rubber piece (bike tube) while fixing on the plates..
fusizoli
On this first one, not important to make that, just cover the grip with sinew.
fusizoli
Make side parallel groowing with that sawblade on the core up to the nocks and on the sides include the horn too.
Use hot and thin glue first. Whan the wood turn shiney it's ok.
mikekeswick
I use a hacksaw blade for the core grooving prior to sinewing.
Edmund Dohnert
Thanks all -
I hadn't given much thought to adding horn or bone side plates, as I just assumed they were more for decoration than for strength. I have some very thin light color horn that I could use, but I'm not sure I want to add side plates, as I am not trying to make a fully authentic museum-quality bow.
I do notice that these bows have a sinew wrap where the grip overlaps the limb. I can see why such a wrap would be important, as this is probably the point of maximum leverage when the bow is drawn, and I think it would be easy for the limb to separate from the grip after some heavy use.
Am I correct in that the sinew wrap would go on after the sinewing of the limbs and the grip are completed?
Also, when applying the thin glue coats prior to sinewing, how long should I wait between coats? Does it matter, as long as the glue has dried between coats?
What thickness glue do you use when actually applying the sinew?
fusizoli
20-25% is ok for sinewing.
Tc
1.The grip and siyah sinew bandage go on after the tillering is done. For the tillering you can use a temporary bandage made of anything strong but removable material to prevent layers' delamination. This is because you might need to remove some material from the horn in that (wrapped)area as well and it is not possible if the final bandage is already on.
2.The glue must be dried before the next coat is on except the last thicker coat which is applied just before sinewing (I use the same glue as for sinewing)
Edmund Dohnert
tc -
Thanks for the advice. That might be good thing to do as a precaution.
I still have a very small amount of horn and wood to remove from the limbs.
My deer leg sinew just arrived yesterday, so I will be spending some time separating the fibers. I haven't worked with sinew before, but it appears to be a fairly time-consuming process to get the fibers separated without damaging them. Any advice about sinewing?
Tc
Just follow Adam's advices, he describes three different methods of sinewing, all of them are good. Some extra/underlined advices:
1. Try to keep everything warm/hot (room, glue, bow core). It gives you more time to work with the sinew before gelling..
2. Soak the sinew at least 25 minutes in warm water.
3. Work with less sinew at a time (it takes longer, but the job is nicer)
4. More sinew on the edges of limbs, less in the middle.
Maybe some practice/rehearsal before the main job would be useful....
mikekeswick
Advice on sinewing.....practise,practise and then some more practise!!
Edmund Dohnert
mikekeswick,
That sounds like very good advice.
I will do some practicing with the shorter, more inferior strands of sinew on some scrap wood just to get a feel for the medium.
I will also carefully reread the section of Adam's book dealing with sinewing.
I still need to separate the fibers of the deer leg sinews (I bought two packages of 10 each, which should be enough), and that will take a while.
For a Magyar style bow, should the ears be pulled together somewhat before or during sinewing, or not at all?
After the horn was attached and material removed, both limbs have developed a slight backward curve (opposite of reflex) such that the belly of the limbs no longer lie perfectly flat but rather curve away from the archer leaving about a 10-mm gap between the limb and a perfectly flat surface. As such, should these limbs be at least pulled together enough to make the limbs perfectly flat before sinewing?
Tc
Yes pull back the ears and give the limbs some reflex before sinewing (it is important now that the bow had developed some deflex) When the glue gelled give it more reflex and some more as it dries. When the bow is put aside for seasoning, the limbs should be about 14-15" away from each other (for your first bow it is enough, on your next bow the tips can touch each other)
Edmund Dohnert
A few questions about sinewing:
1) The bending portion of the limb is a little less than 30 cm long. I am using deer leg sinew. I have very few pieces much longer than 20 cm, and many that are less than 15 cm. I am aware that the sinew layer must extend onto the grip and into the area of the ear. Therefore, there has to be overlapping pieces of sinew.
Adam's book talks about overlapping the layers on top of each other, but I think his book assumes the use of longer pieces of sinew.
So, for the first layer, should parallel lines of sinew consist of alternating long and short pieces, sort of like the way you lay bricks? In other words if Line 1 consists of a 20 cm piece followed by a 15 cm piece, then should the adjacent Line 2 consist of a 15 cm piece followed by a 20 piece? Or should one try to get all the longer pieces in the middle of the bending section and use the shorter pieces at either end, overlapping the layers on top of each other by about 3 or 4 cm?
2) As long as you keep the glue warmed to the right temperature, is there any great rush to get all the sinew in place (as there is when gluing the horn onto the core), or can you take your time to make sure all the pieces are carefully laid down?
3) Can sinew that has been briefly soaked in water be allowed to dry and then soaked a second time without any loss of strength or other problems? (I ask because I have noticed that in sorting pieces of sinew, it's easier to determine length and final thickness if the sinew is wet.)
Tc
1.Yes this is the disadvantage of shorter leg sinew, it is a bit tricky to apply them.. Try to avoid overlapping sinew on the bending section of the limb. If it is not possible then make sure that the overlapping sections are not on each other in the different layers. In the last layer there should be no overlapping in the bending section at all so try to save the longest sinew for this last layer..
2. The problem is not the temperature of the glue (if it gets too cold just reheat it and thats all..) The problem is the gelled sinew. If it is gelled you can not make too much correction unless you heat it up again. So take your time, make sure that the applied sinew is as good as it can be and go on with the sinewing. The adhesion of the gelled sinew is not good you must reheat that area again and this is what we try to avoid - not because it is a big problem but it interrupts the sinewing and slows down the procedure.
3. Once soaked and dried the sinew is adhered and not easy to reuse. I do not recommend it.
jkekoni
Edmund Dohnert wrote:
1) The bending portion of the limb is a little less than 30 cm long. I am using deer leg sinew. I have very few pieces much longer than 20 cm, and many that are less than 15 cm. I am aware that the sinew layer must extend onto the grip and into the area of the ear. Therefore, there has to be overlapping pieces of sinew.
There are bzillion of different methods for laying the sinew. In general they all work. The only thing is that you should NOT have many sinews ending near each other (horizontal) as it creates weak point.
If sinew twists when immersed into glue, the glue is too hot and the sinew piece should be discarded (or coocked to glue)
2) As long as you keep the glue warmed to the right temperature, is there any great rush to get all the sinew in place
No rush. It takes hours to lay all the sinew. I think glue does degrade slightly over time oven in proper heat, but it is not remarkable.
3) Can sinew that has been briefly soaked in water be allowed to dry and then soaked
NO. I would rather shake with hand and put into minigrip and put into freezer.
Sinew backing as whole can be recycled. Google this forum for details.
jkekoni
Edmund Dohnert wrote:
For a Magyar style bow, should the ears be pulled together somewhat before or during sinewing, or not at all?
AFAIK no original exists just fragments(*) , so one-one knows for sure.
(* old information?
Arry
Adam writes in his book to pull the bow a few inches into reflex after the sinew layer has gelled. This way, the sinew, shrinking along its length, does not delaminate. This advice is not for Magyar bows admittedly, but I would assume it is a generally good idea when applying a sinew layer.
Edmund Dohnert
Thanks all for the good advice. I really appreciate it.
I've started preparing the deer leg tendons, and it's a far more tedious process than I thought, but fortunately I have more than enough tendons to select the better pieces of sinew.
I'm going to put the project aside till after Christmas and then probably start applying sinew sometime in January.
Best Holiday wishes to all.
mikekeswick
Once you have pounded the sinew only split bundles into halves. This is the fastest way. Instead of reducing single pieces down to final diameter.
How is it looking now?
Edmund Dohnert
mikekeswick -
Thanks for inquiring.
Right now I am over 3/4 done with the sinewing. I am using deer leg sinew, and now wish I had spent more money to get either the longer elk leg sinew or deer/elk backstrap sinew. Some of the stuff is pretty short.
As even the longer of my pieces don't cover the entire bending section of the limb, I have tried to be very careful in staggering the layering, so that the net effect is a more or less uniform layer. I hope that the inaccuracies cancel each other out.
I have been laying down thin strands, and thus have been pretty heavy on the glue (probably more than I really need). Right now, the sinew layer is roughly 2.5 to 3.2 mm thick. I don't want to make it much thicker, but do want to even out the rough spots. As I have been doing this gradually in thin layers spaced out over days, they appear to be reasonably dry.
So, do you think I really need to wait over 6 months before I start tillering the bow? Or is there a slow reaction between the sinew and the glue?
Right now, I feel my chances of success are something less than 50/50.
Tc
According to Lukas Novotny:
There are many myths circulating on bow drying times. In dry conditions the bow is ready to string in about 3-4 weeks. Lukas prefers to string them after about 6 months, but has found no notable differences in poundage from bows he cured for a month, half a year, or even over a year. When learning the craft, don?t aim for making a masterpiece bow the first time over. It is alright to string it and see how you have done after already a month or so. This speeds up the learning process considerably.
Edmund Dohnert
tc -
Thanks for the information.
I was almost under the impression that the sinew/glue mixture somehow underwent some sort of a mysterious physical change during the 6-month or more 'curing' process. However, if it is just a matter of the sinew layer thoroughly drying out, then in my case that shouldn't take very long because, i) I applied the sinew in thin layers with several days in between, where each layer had a chance to at least partially dry, and ii) it is winter and my basement workshop is quite dry.
I have just completed the last of the sinewing today. To be safe, perhaps I will wait at least a month or 6 weeks before I untie the cord holding the ears slightly closer together and start VERY gently seeing how the bow flexes.
Edmund Dohnert
It's been almost a month since the last layer of sinew went on. I've been flexing it a slight amount and VERY gently. It feels rather stiff.
So, I thought I would do a very light partial draw test. With one limb clamped down to my workbench, I hung a 10-lb weight from the nock and measured the distance the nock was pulled down. I then did this for the opposite limb.
One limb moved downward 3.75 inches (9.5 cm), and the other 4.25 inches (10.8 cm). The curvature looks pretty smooth but is slightly more pronounced in the one that moved the most. Ten pounds on one nock would be about equal to 20 lbs total. Yet that only moved the limbs an average of 4 inches. If the draw weight is more or less linear with distance, this would extrapolate to a draw of around a 120 lbs at 26 inches, which about twice what I intended. The total limb thickness varies from about 13.4 mm to a little less than 12 mmm over the length of the bending portion. Can this draw weight come down much during the tillering process?
I have made some tepeliks but have not used them yet. (Honestly, I'm afraid to, and will maybe wait another month.)
One thing that concerns me is that the surface of the sinew has developed what look like white lines running perpendicular to the limb. These are very thin, about as thick as a human hair and seem to be mainly within the glue, as they do not actually appear to cut through the layers of sinew. In laying the sinew I think I was a little too heavy on the glue, and I also applied a fairly thick glue layer as the last step, mainly to fill in gaps between adjacent sinew strands. What does this sound like and is it something I should worry about? My workshop is in a fairly warm and dry basement, so is it possible that the glue has dried out too fast?
Thanks in advance for any comments and suggestions.
Tc
1. The draw weight will drop down, don't worry. In my experience it will lose min. 25-30% of its current draw weight at the end of the tillering.
2.Those white lines are small cracks in the last glue layer, it has not much significance. You can sand it away when\before you decorate the bow.
3. If you have problem (and you have) with balance and symmetry, use the asa gezi and make the correction by using heat or removing materials from the horn. If the bow is opened enough and balanced, put it on the teplik. If you wait more, the bow will be stiffer....Good luck!!!
fusizoli
Sounds your glue was too thin and-or the Rh was to low and the temperature high.
For the first stepp it is good if the place is warm, but after sinewing have to put it in a cold place to slow down the drying and let it more geling time!
The 12-13mm thickness schould give a 90# bow. This is the rough surface or have you scrap and sand down before mesure it?
Think it schould be an over 70# bow at the end.
If the RH too low, the sinew and glue turn to be brittle! Let the bow few days before teplik at a more humid place on 50% Rh. Thats the best for the glue and sinew too, and take care to hold your bows a place like that ;)
Edmund Dohnert
Zolt?n and TC -
Thanks for the advice.
Those thicknesses were measured with the sinew layer still somewhat rough. If I sanded the sinew layer down a little, I might remove around another 0.5 mm. Should I try to thin out the sinew layer by some light sanding or scraping, or is it best to leave it alone? If I do sand it a little, I would assume that I need to put another thin final glue on after I'm done, just to seal the exposed fibers. (?)
The limbs are pretty much opened up, as the horns only make a little more than a 45-degree angle with the horizontal, so they are not really pulled close to each other, as in a Turkish bow. However, I do have a board on which the bow can be mounted and the nocks pulled back down till the bottom of the horns are at the horizontal. I can tie them in this position and leave them there for a while. Should I do this?
I will take the bow out of the warm, dry basement and put it on the floor of a cold, partially heated room, and maybe leave it there for another month. I can deal with some of the inbalance by carefully removing a little horn.
This is tricky business that makes me very nervous. But I guess it's all about being careful and patient at this point.
Tc
I think the bow is opened enough to be put on the tepeliks. Using the tepeliks is the way to teach the bow how and where to bend so do not try to bend the limbs without them, because the limbs might get unwanted bending.
Use the asa gezi to balance the limbs. At this stage I prefer to use heat to save the horn thickness for tillering. Be very careful, the temperature should not be more than a hair dryer can produce..
Yes, you can sand the sinew and apply thin glue. (however, you will find cracks in this glue layer later on as well...)
mikekeswick
The cracks in the glue are normal and indeed are useful to show exactly where the limb is bending most. They can be helpful in tillering.
Edmund Dohnert
tc and mikekeswick -
I want to be sure I use the tepeliks correctly after I let the bow cure a little longer.
I've made a pair of tepeliks and gave them a curvature that appears to be close to those shown in Adam's book.
Should I start out by attaching the ear end of the bow to the tepelik and then only bend it a little at first, and secure the other end of the tepelik to the limb?
Should I use heat before or after doing this?
Should I leave the bow on the tepeliks in the partially bent state for several days before I untie one end and try bending it down further?
Once the bow is fully bent onto the tepeliks, do I then apply more heat and wait?
As I mentioned previously, the bow is still quite stiff. I've done very some preliminary draw tests which lead me to believe that if I extrapolate those results out to full draw length, the bow could be over 100 lbs. Should I wait for the bow to be on the tepeliks for a good while before I try another partial draw test? Can only so much stiffness be taken out by heating the limbs on the tepeliks?
Should I start scraping some more material from the horn layer?
Fortunately, the bow right now has almost no twist, so at least that's one problem I won't have to contend with.
Thanks in advance for your advice
mikekeswick
Just do what Adam says in the book :)
No heat on the sals at all when bent.
I personally never left a bow on the teplics anywhere near that long. The maximum time I ever used was about 1 hour.
No heat! You should be checking to see if any twist is present.
Once fully bent onto the tepelics you should be able to string the bow for the first time. Of course you are then again checking for any twist.
Don't worry about it being too stiff at this point. Heat won't make it weaker only give you string follow if the sals are heated whilst stressed. This is not something to aim for.
Any bow with a lot of reflex will and should feel stiff to being with.
I remeber my first sucessful bow...I thought this is going to be 100lb easily and it ended up more like 60lb.
Remove horn once the bow is strung if its necessary to lower the draw weight.
Tc
Are the limbs balanced now? If not, again use the asa gezi to balance them. You may use gentle heat or you can remove some horn.
When the limbs are balanced put the bow on the tepeliks (the time on the tepeliks might be hours or days - depending on how stiff the limbs are) You will feel when the bow is ready to string...
When the string is on you can start scraping the horn to maintain balance if it is necessary.
No heat at all when the bow in on the tepeliks!!!
Edmund Dohnert
I have been VERY gently working the limbs onto the tepeliks, one at a time. It seems to be going OK, so far.
Right now, the limbs are not yet fully bent to the tepeliks but I would estimate that they are roughly 80% there. Just a little more.
While one limb appears to be a little stiffer than the other right now, I feel really good that I don't have any twist (at least so far).
One question: From all the pictures I've seen, a true Magyar bow does not have a string bridge. As I am not trying to build a museum-quality faithful reproduction, I am toying with the idea of adding a string bridge, as it has some benefits (such as less rubbing and not requiring as high a brace height). Of course, if I do that, I suppose my bow will be more of a Mongol bow, but I'm not trying for strict authenticity. Any advice?
I haven't yet made a bowstring. I've made some bowstrings out of B-50 dacron for several wooden bows, so I have some idea how to do this. I know that the Turkish bows have a string attached to two removable loops, but I am not sure if I need to do this is on the Magyar bow. From the appearance in pictures, it looks like it's just a regular bowstring with larger than usual fixed loops so they can slide down the side of the ears when in the braced position. Any advice?
Bede
Edmund,
The long loops you see on modern Magyar bows are an anachronism resulting from the 1930s when no straight eared bows had been excavated with recognizable strings. The nearest analogs to the excavated bows available were Manchu bows and those bows had string bridges and long looped strings. When straight eared bows started to be excavated in Xinjiang, a few had string loops still attached. The loops were formed by knotting the ends of the string and were just big enough to fit over the end of the bow. Old paintings survived in China from the time straight eared bows were in use and they show small loops. It is clear that while the methods of drawing bows varied from one end of Eurasia to the other, bow construction was similar for long periods.
Edmund Dohnert
Bede,
Thanks for the scholarly clarification on the history of these bow and what is and is not known about them.
So, if I understand you correctly, I would not be doing anything too terribly egregious if I used a short-loop bowstring as on an English longbow and added a string bridge. I suppose doing so would transform my Magyar bow into a sort of generic asian horn bow.
Bede
I didn't comment on the string bridge because they were not used on straight tipped bows. When a recurve was introduced in the last half of the tip, like the Mongol bows recently excavated, string bridges were added to stop abrasion from the string knot hitting the belly of the bow. Later, with more recurved bows, they had other functions such as returning the string to the centre of the limb to counteract temporary twists.
On those early Mongol bows they were about halfway between the knee and the string nock. Those bows had strings with longer loops and were probably the first to do so. The loop length was not really long until the large eared Manchu bows were developed. Most Arabic manuals specify a loop only long enough for three fingers to fit through.
mikekeswick
Have you get her strung up yet? :)
My fingers are crossed for you.
Edmund Dohnert
Mikekeswick -
No I have not. I'm afraid to.
I have been gradually working the limbs on the tepeliks, but not far enough to get to the point where the limb is fully bent upon the tepelik.
I think as I mentioned early, I've got a lot of those perpendicular fine lines on both limbs, but I've been told that this is normal and are just shallow stress cracks in the outer glue layer. (I was pretty heavy on the glue.)
I have occasionally also heard some faint noises while bending the limbs. After working the limb up and down a few times, these go away even though I'm bending it the same amount. This has me rather nervous.
I don't want to go too far, as it's only been around five weeks since the last layer of sinew went on. However, it's been pretty warm and dry in my basement this winter, so I think the drying has been pretty fast (maybe too fast).
I also did some preliminary weight tests this morning. I clamped one limb firmly to my work bench and then hung a weight on the free limb. I did this with 10 and 15 lbs (equal to 20 and 30 lbs on both limbs), and got a downward movement of around 4.25 and 6.75 inches, respectively, both limbs being almost exactly the same, and fortunately, no twist. If the draw continues to be more or less linear, this would translate into a draw weight of around 110 lbs @ 26 inches, almost twice as stiff as I want it to be.
Should I continue gradually working the limbs or start to remove some horn? Is it advisable to remove some sinew also, or best to leave that alone? As the wooden core slightly overlaps the horn layer, I suppose I could remove a little material from there, but to do that I'd have to remove some of the sinew that lies on the edge of the core. Or would it be best if I just let the whole thing rest for another month?
Edmund Dohnert
mikekeswick -
Regarding my last message, I don't think I properly took into account the actual geometry of the fully drawn bow. My best guess is that if the bow is held in the vertical position and if the nocks of the bow when fully drawn more or less are orientated exactly opposite to that of the unstrung position, i.e., 40 degrees forward versus 40 degrees back, than we are probably talking about a linear displacement of roughly 16 inches, not 26 inches, which is the full draw length at the string.
As such, it would appear that a 6.75-inch movement at an equivalent draw weight of 30 lbs would be equal to roughly 75 lbs rather than my original projection of 110 lbs. In which case, I am probably not far off of my intended draw weight of 60 lbs. Of course, we still have that little matter of getting it to bend that much without breaking.
Does this sound more reasonable?
mikekeswick
Trying to predict draw-weight from an unbraced reflexed bow....wait till you have the string on before thiunking about measuring the weight.
You have plenty of horn thickness to adjust the draw weight if necessary.
I don't know how many bows you have made so I don't mean to patronise if you already know this but draw weight is measured from brace height onwards. Very reflexed bows intially appear very stiff but once strung it can be a different story.
As for the noises it could be the glue in the sinew layer cracking which isn't a fatal problem but it can be very unnerving! The first ever sinew backed bow I made did this because I had used the glue at too high a concentration....It made those cracking noises every time you drew it...but that was because the glue was very,very thick. Other potential causes are layers delaminating, sinew layers seperating or the core breaking under the sinew. Try to catch where the noise is coming from.
Edmund Dohnert
mikekeswick -
Yes, I realize that hanging a weight on the tip isn't the same as putting a fully braced bow on a tillering stick. I just wanted to get a very rough idea of where I was. Based on what you've said, I now realize that since the geometry of a highly reflexed bow changes so much over the draw distance, it's probably futile to try to predict draw weight at this point.
That faint crunching sound certainly is disconcerting. It's hard for me to tell exactly where it's coming from, but it seems to be somewhere in the bending section. I have also noticed that those perpendicular fine lines I previously mentioned appear to be more pronounced, but I have not observed any visible signs of any sinews actually parting. Could this just be the weaker parts of the sinew layer permanently stretching rather than the beginning of a core failure, or is there really no way of telling until something gives way?
I am pretty confident that I have a very good uniform bond between the core and horn layer, but less so about the integrity of the sinew layer. The sinew was applied with the hide glue at around 20-percent concentration. (This was after sizing the upper core with glue at less than 10-percent.)
I suppose I should just very gently and gradually work the limbs onto the tepeliks and see what happens. At the risk of inducing string follow, would it help if I warmed the bow up a bit with a heating pad, to say something around 90 degrees F? My basement workshop is around 68 degrees F and rather dry at this time of year.
mikekeswick
If the core was failing then the sinew would be whiter in just that part and it would be obvious.
Yes the only real way to know other than the sinew/glue getting more of these cracks is to pull it further.
fusizoli
If the shop is dry, than put the bow at a more humid place for a few days.
After the dry shop if warm it up more, the glue chould be more brittle.
First of all, have to open it and uniform the the two limbs, just than pull on the teplik. Adam wrote the method in his book.
Edmund Dohnert
mikekeswick + Zolt?n -
I do have some white sinew, but that is only because I sanded down some of the rough high spots not long after I completed applying the sinew. This white sinew was there well before I started the tillering process and runs totally parallel to the limbs. There are no localizing perpendicular white areas or raised areas indicative of pending core failure.
Yesterday, I got 'Limb B', the slightly stiffer of the two limbs, fully onto the tepelik and left it there overnight. I was expecting the worst during the last part of the bending, but there was no crunching sound at all. After I took it off the tepelik, there was some set, but the bow started to recover to its original shape after a few hours. I am cautiously hopeful, but will hold off on doing the other limb.
I will take Zolt?n's advice and move the bow to a more humid part of the house, namely the upstairs bathroom, before I try the other limb.
What do either of you two think of the idea of making a little 'tent' out of plastic sheet and putting the bow in there with a wet rag (not touching the bow, of course) for a few days? That should really create a very humid environment. Or maybe too humid?
Edmund Dohnert
mikekeswick + Zolt?n -
I kept the bow in the upstairs bathroom for almost two days, where it is much more humid than in my basement.
This morning I managed to get both limbs fully tied down on the tepeliks without any problems. There was absolutely no crunching sound or signs of sinew failure when I did this, so I am encouraged. The ears are almost parallel to the grip, so I probably don't have to flex it all that much more to get a string on it.
I still need to make a bowstring for it. (Will use Dacron B-50 from which I've made several self-bow strings.) Should I leave the bow on the tepeliks for another day so, or would it be best to remove the tepeliks and then put them back on once I have a string ready?
Edmund Dohnert
Zolt?n, mikekeswick, etc -
I an now at the point where I could really use some good advice.
I put the bow on the tepeliks I had made, and I got both limbs down pretty tight, and there was absolutely no crunching sound as I did this. Whew!
I then managed to get a makeshift bowstring on it, albeit one at a pretty shallow brace height (only about 4 inches), as I am still being rather timid.
While I feel fortunate that I have absolutely no noticeable twist in the limbs, I do have a definite imbalance if the curvature and deflection between the two limbs. One limb (let us call it 'Limb A') is much stiffer than the other and has a curvature that is consistently 1.5 to almost 2 cm deeper than the other. It is quite noticeable.
I have taken careful thickness and width measurements along both limbs, and they appear to be almost identical. Yet limb A stubbornly refuses to bend as much its opposite limb. I have scraped some material off the horn layer but have not seen any results, and am reluctant to do much more scraping. (Might this be a problem in the sinew layer, such as the sinew in Limb B perhaps stretching more than that in Limb A?)
I can equalize the curvature of both limbs if I wrap a band around the weaker limb near the string bridge, thus flexing the stiffer Limb A. This seems to make both limbs look the same, but is hardly a permanent solution.
I have done some very preliminary tillering, and right now, I get around a 12-inch draw when the string is pulled to 25 pounds. If the remaining draw is linear, that would suggest something over 50 pounds at my comfortable short draw of 26 inches. I have not pushed the tillering further at this point.
So, should I continue nibbling away at the horn layer of the stiffer limb, use some heat to make it behave, or perhaps even add an additional layer of sinew to the weaker limb? Or should I just accept the fact that one limb is going to flex more than the other?
I don't want to do anything further till I get some advice by you all who know what you are doing.
mikekeswick
Personally I would simply remove horn from the stiffer limb. If the two limbs have different strengths they must be made equal. Bear in mind that the lower limb (when shot by hand) will need to be a shade stiffer than the upper (due to the different forces drawing by hand puts on the limbs).
Yes dimensions will certainly get you 'in the ballpark' but tillering is where you either make a good bow....or not!
So make the limbs even and once the bow looks good at a certain draw length then obviously you can draw it a little further.
I would advise drawing by hand once you get to 18 inches or so. It's useful to take pictures of the tiller with the bow hand drawn.
Also it's better to brace it a little higher, somewhere around 6 inches.
Good luck!
You must get a picture of this bow for us!
Edmund Dohnert
mikekeswick -
Thanks for the advice.
I scraped some more horn off the stiffer limb this morning, and now the differences between the two limbs is less than 1 cm at my currently shallow brace height, but then becomes almost indistinguishable once I put 15 - 20 lbs on the bow. The curvature of both limbs is also much more symmetrical now. As such, I am inclined not to mess with it anymore for now and will start gently and patiently tillering after I get a tighter string on there to bring the brace height closer to 6 inches.
I will try to get some pictures the next time my son and daughter-in-law come down for a visit.
Arry
Edmund,
sounds like a success! But maybe leaving the barshak band on the weaker limb for a few hours, maybe overnight, would have been sufficient, too. It helped me balance my bow, at any rate.
Looking forward to those pics!
Cheers
Jarek
Edmund Dohnert
Jarek -
Thanks for the encouragement, but I won't consider it a success until I am able to repeatedly pull it to full draw without something giving way. Right now, I've drawn it to 18 inches, and so far so good. I will be gradually working the bow and increasing the draw. As I'm a short guy, my comfortable draw distance is only 26 - 27 inches, so that's what I'll be aiming for.
I suspect it will be around a 50-lb bow at full draw. At first it felt that it would be a lot stiffer, but after working it and removing some horn to balance the limbs, it no longer feels so stiff. I also have some string follow, but the bow comes back if left unstrung for a day.
Just an indirect question: If the bow turns out to be too light, is it practical to add an additional thin layer of sinew to increase the draw weight even though the original sinew layer was put in place several months before? Any special preparations when doing this?
Edmund Dohnert
Well, since I strung the bow a little over two weeks ago, I have been giving it a twice-daily workout, repeatedly drawing it and gradually going further beyond mid-draw.
I've heard a few minor groans along the way, but they have not recurred. I have now been able to repeatedly draw the bow to my intended 26-inch draw length, and so far I've had no problems. The limbs are very symmetric, there is no noticeable twist, and the bow has a nice smooth curve when fully draw (at least it looks that way to me.)
As I've just been hand tillering it, I don't know the precise draw weight, but it feels like about a 50-lb bow at full draw. I've shot it a couple of dozen times, but only down my basement. It appears to have pretty good power.
I need to make a better bowstring, as this one was only makeshift for tillering purposes. And I want to maybe reposition the string bridges that I put on, more or less as an afterthought.
well, I think I've got a bow! Not too bad for my first attempt. I'll try to include some pictures when my son and family visit in a week or so.
I want to thank Z?ltan, mikekeswick, and the others that have generously provided good advice and kept me from of making serious mistakes.
mikekeswick
Eagerly awaiting photos! :)
Jake Levi
Edmund this has been a fascinating read !!
Congratulations on your bow !
In the fwiw category the TBB has excellent information on sinewing. I havenot changed my use of it since first reading of it there.
You have had some incredible coaching here, awesome !
Along with your coaches I am looking forward to seeing your pics.
