Primitive Archer
Main Discussion Area => Bows => Topic started by: Lehtis on November 10, 2017, 06:46:37 am
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Greetings from Finland!
Dark autumn evenings and some spare time to spend... To make (flight) travelling easier I decided to make a couple of TD bows for myself. The project started by selecting suitable timber from my workshop corners and I made the sticks 4 cm wide and 1 m long. Both bows will have Hickory back, ca. 5-6 mm thick. One bow will have ca. 5 mm Cumaru core and Osage Orange belly. The other one will have ca. 5 mm Osage Orange core and Bulletwood (= Massaranduba) belly. I glued the parts with Unibond 800 and squeezed them together with rubber stripes cut from bicyckle tubes. I bended the nock ends ca. 7 cm upwards. After couple of days curing I narrowed the limbs to 30 mm wide and now they are waiting for the metallic connector pieces to be fitted on. Until then...
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Some progress... Connector pieces fitted and glued with slow Araldite. Limbs ca. 27 mm outside of the connector pieces. Next to draw the string line and saw out the limb shape...
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Looking good. Can't wait to see the completed bows.
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Thanks, Pat.
Now the connecting pieces fitted and limbs band sawn to proper width.
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Very clean work. I appreciate that.
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Slowly proceeding... limb backs rounded and smoothed and ready for bending. Next rounding the bellies and tillering during December...
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That bulletwood bellied didnīt want to co-operate. Tillering with long string went OK but when trying to put short string on I got some firewood... :-(
Perhaps that hickory was not best quality, some starting rottening or something. At least that piece is darker, as seen in the earlier pictures, and it exploded just there.
Now I’ve decided to try to make new lower limb to pair it with the undamaged upper limb.
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Osage bellied one is in better mood and now at adult poundage waiting for horn nocks and fine tuning of tiller.
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Lethis, looks like the back failed causing the belly to fail. Too bad. Hope the other 2 hold up better for you.
If it is OK with you, I may move this post to "Bows" so you'll get better coverage. Let me know if it is OK.
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Thats OK to move.
And Im going to try to make new low limb to pair the undamaged upper limb.
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How wide and long are the bows when assembled and what poundage you want from them?
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Darn! hate it when that happens! Lucky the osage one seems to work out well! Those takedown things look good too, been wanting to do one for a while and looks doable the way you set it up. Nice!
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To FilipT: The bow(s) will be man tall, a bit over 180 cm, so the halves with normal travelling stuff will fit in 40 inch bow bag made for travellers with two compund bows (I don’t have any). They are ca. 28 mm wide just at the handle peaces and narrow to 14 mm at rounded tips. They should be ca. 80-85 lbs @ 28” when ready for shooting.
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Nice looking work, shame about the blow up :(
Del
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Lehtis, I thought they were much wider, that perspective played tricks on my eyes. For such narrow bows you will get pretty strong bow, that is really cool.
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Yeah, they would be more durable if the limbs were wider and thinner... but cause Iīm mimicing ELB stylish bows, the widest part of the bows should be at the handle area. The TD sleeves set the max width limit to that 28 mm.
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... and the story continues... the parts of the new lower limb glued as before... the broken one set there to frighten and teach the new one to behave...
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Cool build along. That stinks with the broken limb but osage is king. ;D :BB
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Good recovery, Lehtis but those bows don't scare that easily. ;)
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Cool work, Lethis!
And a nice workshop, I see you have a luxury heating inside - that would cause me staying in the shop all time, ;D ;D ;D
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Simson: Our houseīs central heating is not on yet. Too mild winter so far and my workshop is in cellar below the ground level and I have a fireplace there... :-)
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:'( This bulletwood bellied billet really doesnīt want to turn to a bow. Something odd happened in the gluing process and the bullet-osage joint popped before trials to bend it. Perhaps there was residues of wax left on the bulletwood slice (been on exhibition terrace before I got it). I planed it only gently and wiped with acetone before gluing... Another reason might be that my Unibond was old but it was looking quite normal and was freely running when I was mixing it... Now Iīm a bit afraid of whatīs going to happen with that osage bellied bow. It was bending properly yesterday when I was starting the horn nocks... letīs see how this story ends.
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I guess that is all a part of bow building, but I sure hate it when a plan don't come together. Good luck with the redo, still watching and look forward to the final finish, remember patients is a virtue in life, but especially in bow building . ;) :)
Pappy
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I would remind you to clean the osage very well,i clean it till i dont get any more yellow color on a white cloth.your wotk looks to very attentive,bet you end up with fine bows.
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Hickory-Cumaru-Osage TD proceeding. Horn nocks now raw shaped and the bow is ready for test shooting tomorrow morning. Lower limb looks a bit stiff and tiller unbalanced but thatīs on purpose because of in many cases they seem to start bending more when in use. I hope it looks better after some tens of arrows. In this condition before final smoothing it gives 82lbs@28".
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The outer portion of the left limb looks quite stiff. Be sure it doesn't hinge where it is bending while drawing. How far have you drawn the bow the way it sits now? You won't be able to tell good tiller until you hit full draw.
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After test shooting it strongly looks like "EIAC 2018 @ Budapest, here we come!" The bow behaves well and itīs ready for finalizing, i.e. horn arrow pass, smoothing and oiling, leather handle and new string. My third five arrow set from 20 yds in the attached photo when testing the bow this morning.
Tiller changed during shooting as I expected and itīs now proper 4-5 mm measured at 25 cm from handle pieces. I draw some 27-27,5" and the bow gives now 82-83lbs@28" and 77-78lbs@26". Pictures after test shots in my next message.
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Pics after test shots:
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She looks pretty good. Nicely done. Too bad about the other two. Hopefully you will be able to rescue them. :OK
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Latest one looks good.
Shame about the bulletwood etc. Old Unibond might be the problem, as you have already mentioned. What type of clamping method did you use?
Do you sand your mating surfaces or handplane/scrape?
That complete delam, I have only had that happen with an old formula west systems epoxy. Shouldn't happen with good Unibond. As others have said it could be the oiliness of the osage. It also could be too much clamping pressure starving the glue joint. You can usually get around that by roughing the surfaces with 40grit paper and a sanding block.
It will be a fair bit of work to clean scrape/sand the glue joint clean, but they look like good quality(expensive too) materials so it would be worth the effort. Soak the ferrule in a bath of acetone, it should loosen after a day or two.
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To Hamish: See the earlier pics in the chain; rubber stripes used to to squeeze the glued billets. In the last gluing I didnīt sand the planed surfaces, which I usually do; only acetone wiping done. I may have also tightened the rubbers too tight in this case and all these together may explaing the failure.
Now the osage-bellied has just got leather over the handle. After final smoothing and oiling and yesterdayīs shooting-in the string the scale shows now 80lbs@28" and 71lbs@26". Final pics later this week...
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Hickory-Cumaru-Osage Orange "Xmas" Bow ready for action.
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Bow looks very professional. Nice work.
The de lam is a bit of a mystery. It sounds like you did everything pretty much well. I know plenty of guys that hand plane the surfaces and use unibond, no problems.
With rubber bands you won't have starved the glue joint, with excessive pressure. Sounds like it must have been an old batch of glue
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Not so happy end: These bows really didnīt want to fly with me... :-(
Now that Osage-bellied one decided to explode this morning while shooting Flint Round. Looks like hickory backing gave up at brass ferrule joint where the growth ring has been violated. Got some 300 arrows shot before explosion.
Plan B in mind in case I want two bows in luggage or got to travel with ski bag and PVC pipe to carry solid longbows.
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Very sorry to see that,but i believe you called the problem correctly
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Sometimes things go wrong, even when they theoretically shouldn't. Lots have guys into bowmaking have been there too so we know your pain.
It could be a number of factors, as you have already mentioned, you definitely don't want a step in the backing near a ferrule. Shooting in extremely cold weather can be dangerous if the bow is not overbuilt. Draw weight increases but tension strength doesn't.
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I think not sanding the surface was your problem. I haven't degreased anything in over 10 years. I like my surface sanded about 60 grit and then I just wipe off with a damp rag. I do this on ipe, bulletwood, and osage. You obviously know about violating the back now. Just out of curiosity would you mind taking the physical weight of these bows. I have been doing some 80# and 90# bows lately with similar designs but 1 piece.
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Badger, I donīt have not weighed these two broken ones but I measured some other of my ELB stylish bows:
Hickory-Ipe-Osage Take-Down, 72,6", 78lbs@28", 910g (metallic connection pieces increase weight)
Bamboo-Ipe-Osage, 71,3", 79lbs, 680g (leather handle wrap removed and this one will be converted to TD soon)
Hickory-Ipe-Osage, 72", 78lbs, 750g
Bamboo-Ipe-Osage, 68,3", 83lbs, 670g
Bamboo-Ipe-Osage, 70,5", 70lbs, 640g
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Due to failing with these two TD-bows I had to try to modify an older bow to TD as described in another chain:
http://www.primitivearcher.com/smf/index.php/topic,60847.0.html
Now Iīve got two bows for easier flight travelling.
Hereīs the last message copied from that chain:
"Forced-to-Retire" Bamboo-Ipe-Osage reborn as a TD-bow (carriage bow) and back at work. That tiny starting splinter superglued and tied, TD-connectors installed and covered with leather and the bow TruOiled several times. Scale shows now 78lbs@28" and 73lbs@26". Some pics added; full draw as in the original full length format in the beginning of this chain.