Primitive Archer
Main Discussion Area => Bows => Topic started by: WilltheArcher on April 05, 2015, 03:14:00 am
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Hi guys. Cody at Tenbrook Archery recommended I post here and ask a couple questions. Great forum you got here, I've been pouring through the build-alongs and they've been really helpful. Long story short, I’m a grad student building a longbow for a design class. I have to make it out of wood and metal.
I am making a 3 piece takedown longbow. I will cast the central grip out of aluminum (it’s actually fairly light) and make the two limbs out of a wood laminate. Probably bamboo and ipe. Cody and I decided for my first bow it would probably be best to keep it a straight bow. So my grip mounts will be straight (no reflex) as well the bow limbs, and it’ll have that old school D shape when I string it.
I’m planning on following the process at makingtraditionalongbows.com (http://www.makingtraditionalbows.com/how-to-make-a-longbow.html) to make the wood laminate of bamboo and ipe. I still have a few questions.
- How long would you recommend the riser be? Cody recommended I try about an 18” riser.
- How long should the bow be in total? I’m a 6 foot tall athletic male. Cody recommended 70” nock to nock.
- The cross section. Some sites, like the makingtraditionalbows I'm planning on following, round it off into a D cross section. Others keep the cross section rectangular. Which should I go with?
- Most importantly, the directions on makingtraditionalbows.com (and everyplace else I’ve looked) are for making a one-stave bow. To make two separate limbs, should I follow the directions and then cut it in half at the centerline? I could then take off about ~6 inches on the end of each limb to preserve the 70” length when I mounted them to my riser. I’m not sure if there’s something I’m missing here though.
Any and all advice appreciated. Thanks!
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My advice is to start simple and slow.
The longer the working limb the less strain on it.
Del
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are you building a three pc takedown or a two pc, if a two pc 18" is way to much of a riser
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are you building a three pc takedown or a two pc, if a two pc 18" is way to much of a riser
Hi Bubby - I'm planning on making a three piece. A central riser with two wooden laminate limbs.
I guess my main question is about the two bow limbs. I figure I could make a one-piece like most of the tutorials do, then cut the two limbs off leaving the handle area. Then mount those to my riser and tiller. It's the best idea I've got so far but wondered if anyone would recommend another method.
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I've built several all wood three pc bows, no need to build the one pc bow and cut, if you have a 18" riser figure 2-1/2" beds for each limb to mount to if a 18" riser I would make the full length of the limbs 28-1/2" long and I would use 1/8" lams back and belly hard maple, you can make the core the same or use walnut or something else for contrast make them all the same 1/8" thickness, 1-3/4" wide at the riser for the full 2-1/2" then a straight taper to 1/2" tips this will almost tiller the limbs
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here's one I did a while ago http://www.primitivearcher.com/smf/index.php/topic,24354.msg327043.html#msg327043
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Bubby that's awesome. Really helpful for me to see.
So you recommend 28-1/2" limbs, and taper the width from 1-3/4" at the riser to 1/2" tips. What about the thickness, that needs to taper too right? What should the thickness be at the riser bed and at the tips?
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nope no taper on the limbs with a pyramid limb the thickness is pretty constant, at the riser bed if you look close I made a walnut overlay on mine and had zero problems
remember when you get to the point after glue up to round all the edges of the limbs both back and belly
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nope no taper on the limbs with a pyramid limb the thickness is pretty constant, at the riser bed if you look close I made a walnut overlay on mine and had zero problems
remember when you get to the point after glue up to round all the edges of the limbs both back and belly
Hmm, is that because it is a takedown bow? Everything else I've read tells me to taper both the width and the thickness, like this Hazelnut bow build-a-long (http://www.primitivearcher.com/smf/index.php/topic,3895.0.html) on Primitive Archer as well.
So if I keep the thickness constant, how thick do you think I should make the limbs?
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that's a great build a long, but you probably didn't notice that the limbs are the same width till 12" from the tip http://i793.photobucket.com/albums/yy217/gferlitsch/HazelnutBuildALong/hzb019.jpg
with a pyramid profile like I suggested the taper is in the width profile and not thickness, although you will end up with a minimal , and I mean very minimal thickness taper after tillering
http://www.primitivearcher.com/smf/index.php/topic,35312.0.html
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Ah you're right I didn't notice that. Well cool if I don't have to taper the thickness that makes my life a lot easier! What thickness would you recommend? I'm a pretty strong guy but it's also my first bow so I'm thinking 40# should be about right. That link you gave me was a thickness of about 1/2".
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Three finished/sanded lams 1/8" thick should get you in the ballpark, but you can go 1/4" on the belly and be sure
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Cool. I'm still planning on using a bamboo and ipe laminate. I wanted to go 1-1/2" max width but the ipe I have is a hair under 1-3/8" wide so I'll have to make that work. I'll try 3/8" on the ipe and 1/8" on bamboo and see how that works. Might be a little on the stiff side.
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One other question - I notice on your riser the ledge for the arrow isn't at the center. It seems like it oughtta be at the center of the bow when you draw back and fire but I notice on most risers it's about an inch higher than the center. So this is fine?
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With boo and epe 1-1/4" wide is plenty and 1-1/4" up from center is where i usually put a rest
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Is your riser 1.5 inches wide at it's maximum? I'm trying to size my riser to the width of my laminate but that seems pretty small for my hand to grip.
Do your limbs only taper after they leave the 2.5 inch riser bed? Or is the riser bed tapered to match them?
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Make the pad area the width of the limbs and i have fairly big hands and my handles are maybe 1-1/4" in thr mid grip, dont taper till after the pad
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I spent some time on http://www.learn-archery.com making sure my estimates for draw weight, length, and bow height seemed about right. Since my draw length is 29 inches, the weight I'm going for is ~40 pounds, looks like my bow length should be about 70 inches - which is what Cody at Tenbrook Archery said, so we're good to go.
So my question is - how far down from the tip of each limb should I put my nock or the bow string? Half an inch? I'm realizing I'll have to increase the length of each limb just a little bit from what you recommended, because if I made them 28.5 my bow would be 70" from tip to tip instead of from nock to nock.
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Any wood past the nock is just dead weight.
But...
You need enough to stop the string going right off the top nock as you slip it into the groove when stringing it. On the bottom nock you need enough bulk to stop any damage to string of bow from the inevitable scrape on the floor.
You can make pin nocks which don't stick out any further than the string if you really wanted. Don't overthink it, just go with what you feel looks right on the bow.
Del
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Thanks Del.
I've got another question. So the plan is about 3/8" ipe and 1/8" bamboo laminate. I'm working on planing the bamboo now, but I'm realizing it's not a constant thickness of course, because it's rounded. Is it 1/8" at its thickest or at the edges?
Also, should I round the edges of my laminate limbs?
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In between the nodes, 1/8" in the center to 1/16" at the tips
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That is after u have cut the profile out of the boo
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Awesome thanks! How much better than an ipe/ash laminate is an ipe/boo laminate? Gonna be a little hard to work with the bamboo and considering going to ash.
My ipe came out a little thinner than I thought. Boo/ipe (or boo ash) looks like it will be about 7/16" thick. Think I'll still get a 40 lb draw weight out of it?