I'm looking to make a 64"55#28" longbow using the longbow blueprints from 3rivers. I'm using my own lams which are parallel cut. My question is this: How thick do I go? I have verying opinions, Crooked stik made my lams for me on my first bow and he hit the poundage I wanted dead on but the problem is that he uses tapered lams. I called Bingham and was told .322 if I was using parallel lams. My riser is 18" fade out to fade out. I'm just a little nervous due to the cost I have in the wood on this one and my first bow was .475 it's specs are 66" 51# 28". I want to use bocote as the outer lams with bamboo as the core lams. The riser is bocote, zebrawood and osage accents. I would be very grateful for any help. Thx.
Bill
I dont think you are going to get many confident answers...I am still hoping to hit weight nowadays...and when I change one little thing, I'm usually off 5-10 pounds...
Binghams is probably your best bet...
Ernie
Daddy. it is hard to call the shots on different bow designs, especially if you change things. I have some (but not a lot) experience with building bows and I wonder how you got only 51# out of .475. On the forms I have, I believe I would exceed 100# with that much wood.
Just curious (want to learn more here) why use only parallels, unless that is just what you have ? I would think that haveing some amount of taper in there would allow for less tip weight (albeit not a whole lot less) and maybe a bit faster recovery.
I think you will change your whole limb shape / tiller profile by changing to all parallels.
Can't wait to hear from others on this one.
ChuckC
i need about 0.32" for 50#@28" on a 66" longbow.
the form is a mild D/R form and i am using 0.4 glas on that one.
i suggest a overall taper of 0.3 for this.
if you do it with out taper,you end up with a slow bow with handshock.
thats my experience and might not be what others found out.
grinding a parralel lam is just as difficult as grinding a taperd lam by the way.
shantam
By memory,.360 @ 64" on my D/R form(own design) is 55#,.380 @ 64" is 65#.Thats the only 2 64" bows I've built,so my experience is limited. I think your limbs are gonna bend a LOT just off the fades. Mine bend more than I like using a .002 taper,we're gonna try a power lam(think thats what its called),another taper that runs out bout 5-6" past the fades on the next one. Don't know if it'll work,but heck its only money!! Good luck and keep us posted!
Hey Kenny, how about just making the riser a tad longer instead of trying to place and maintain that short taper in the mix..
ChuckC
btw. im building a 66" longbow over the weekend on a new form.
if the tiller turns out ok,
i can sent the pattern and corethickness to you WA.
shantam
ChuckC the butt thickness on the lams I sent was .400-2 .100x,002 tapers 2.100x,001 tapers plus whatever glass was used.
I agree that with all paralells the strung profile will probably be different with all paralells. It will work ok. When you do a limb with a reverse taper setup provided you use two tapers with the same butt thickness you end up with a paralell limb thickness. The reversed taper goes on the belly so it bends around the fade curve easier.
Crooked...is that first number correct ? .400 ? I am not quite following...is that the total thickness of all the lams or just that one ? That is nearly half an inch thick ! Should it be .040 as a parallel, two of them ?
Actually, it doesn't matter what the butt thickness is of the tapers, if you use a reverse taper of the same taper rate, it equals a parallel.
If you tie in those .100 tapers (as you describe above) using one as a reverse taper, have you calculated which taper is going in as a reverse ?
Please show pix of your bow when you finish it, I really enjoy discussing and learning more about this.
ChuckC
chuckc, On my first bow crooked stic sent me the lams for it. He sent me two .100 butt thickness with a .002 taper and two .100 butt thickness with a .001 taper. I used .040 glass. So the total thickness was .480 that bow was 66" 51# 28". My problem is that I want to learn how to make my own lams. I found a way to make parallel and I have a way to make the tapered but I need a tapered lam to make the guide for my sled. How I made the parallel lams was by using a square board clamped to my bandsaw I cut the lams just a hair over the size i was looking for due to some wood not cutting straight. I then used a drum sander in my drill press and using the same square board i clamped it to the drill press and ran a scrap pieace of wood between the wood and the drum sander until I got it to sand to the size I need. I'm going to make the tapered lams the same way but i will use a tapered lam a straight board and the lam I want tapered, run them between the board and the drum sander. On this bow I want to make it a little shorter 64" that is why I asked the question about the thickness. My riser is 18" fade out to fade out. Bingham told me .322 for the length using parallel lams. Now you said just using parallel lams will make a bow slower I don't want that should I wait until I learn to make the tapered lams?
Bill
Chuck,we've been kickin that around too.
Thanks,Kenny
Bill,are ya measurin your reverse tapers at the center of the bow or figuring the full .100"?
what do you mean by reverse tapers? i used my gauge and measured the thickness just past the fade out. is that correct?
bill
Wyatt. Slower is a descriptor that can mean many things, from Wayyyyy (less fast) to kinda (less fast) to just barely (less fast). I don't know which it will be, or even if it will work that way. Some of this stuff is way beyond rocket science and some is just common sense.
It ...seems.....right that if the ends of one bow are heavier than the ends of another, the lighter bow will recover quicker, or faster. But, other things might also influence that, maybe more so.
Example...in design....a Hill style bow with a very short handle and long limbs might take longer to recover than a very short bow with a longer riser (shorter working limbs). But...As soon as that is said, someone is gonna yell how their Hill style bow is lighning fast. There goes that theory...or does it.
I still am having trouble following your calculations. maybe that is why I have such questions. If you used .040 glass and only those tapers (were they 36" pieces ?) I add up to only .280 thickness. Did you use parallels also ?
If you want, you can PM me a tele number and I can call you and talk some time.
ChuckC
Bill,I think Binghams measure lam thickness at the thickest point,center of bow or thick end of tapers,(don't think they use reverse tapers,taper turned with thin end to center of bow)
I've never used reverse tapers,so when I talk limb thickness,its: glass + paralells+taper at thick end.
Hope this helps and I'll let Chuck take it from here cause he's doin a way better job of explainin this stuff and I'll prolly just confuse ya!
:wavey:
This bow in the pic has two .100x.001 tapers and two .100x.001 tapers with .040 glass. It weighs in at 50 at 26 in my design.Thats .480 butt thickness. (http://img.photobucket.com/albums/v75/crookedstic/Strung.jpg)
Was I wrong!! Helped a fellow glue up a Binghams TD pronounced longbow limb today and guess what, reverse taper!! Didn't have time to mike and see if they used the same amount of taper in both,but I'll check when we glue up the other limb.
QuoteOriginally posted by ChuckC:
[QB] Wyatt. Slower is a descriptor that can mean many things, from Wayyyyy (less fast) to kinda (less fast) to just barely (less fast). I don't know which it will be, or even if it will work that way. Some of this stuff is way beyond rocket science and some is just common sense.
It ...seems.....right that if the ends of one bow are heavier than the ends of another, the lighter bow will recover quicker, or faster. But, other things might also influence that, maybe more so.
Example...in design....a Hill style bow with a very short handle and long limbs might take longer to recover than a very short bow with a longer riser (shorter working limbs). But...As soon as that is said, someone is gonna yell how their Hill style bow is lighning fast. There goes that theory...or does it.
I believe those really fast "Hill Style" bows you were refering to are fast due to more than than the typical amount of laminations with good tappers to the lams too..... i just read something along those lines abow Hills bows.
QuoteOriginally posted by kennym:
Was I wrong!! Helped a fellow glue up a Binghams TD pronounced longbow limb today and guess what, reverse taper!! Didn't have time to mike and see if they used the same amount of taper in both,but I'll check when we glue up the other limb.
What would be the atvantage of a reverse taper????
Don't know,maybe when we get this one strung up,it'll shed some light on why? I use tapers in all mine.I noticed on the sheet that came with his bow kit,the less reflexed longbow uses 1 taper and the rest paralells.?
Well I glued it up tonight. I went with Bocote parallels .060 on the face and the back of the bow. Bamboo core lam with a butt thickness of .100 with a .001 taper. I made the taper myself with the help of some people here on tradgang. .050 glass. Binghams told me to shoot for a thickness of .322 for the specs I want: 64" 55# 28". I'm giving it a shot. Man I hope it works out.
Bill
3 hours in the oven only 1 to go!!!!!
Bill
good luck bro.
i know how you feel.
shantam
Hey there Bill,
I've been following your thread here, and share your concerns and excitement as well. i just put my first riser in my brand new oven i built yesterday!i've got a pronounced longbow kit from Binghams and am using the air preasure form system. boy there sure is a lot of work in building the forms!
Before i glue up my first bow today i'm going to use the tapers i have with the kit to grind sled for making more. I've got a bunch of different hardwoods in stock. i want to make my own laminations for future bows. This taper thing seems to be a well kept secret. i have found no books what so ever on the subject, and many bowyers are pretty tight lipped about sharing their experience.....
I hope you plan on posting a few pics....i'm looking forward to seeing what you have going
the taper thing is no secret.
with the among of taper you can control the point where a given bow will start to stack.
less taper,less or later stacking.
on the other hand will a bow with just a bit or no taper (parallel) have heavy limps and tips and therefore this bow will have more handschock and will be slower due to the to heavy limps.
also at least in a longbow you want stiff tips,lets say the last 10" or so.
to much taper will weaken the tips and you will loose performance.
so the goal is to find the middle of 2 worlds.
and this is hard to tell without knowing the form you or anybody else will build your bows.
i need at least 3 bows out of a new bowform to feel
comfortable and hit the disered drawweight and stacking point.
thats why it is hard to find somebody to tell you how much taper is needed.
they simply dont know it,cause the dont know your bowform.
i hope this clears the "secret" a bit
sorry for my english by the way.
shantam
I'm beginning to see the picture now. :banghead: I have learned a bunch this weekend.... 1st bow in the oven tonite! This one peice long bow was a good one to start with i'm thinking....
I'll be starting on Limb forms for the take down recurve later this week if i have time..... Those should be eisier by far than the long form, and a whole bunch easier to glue up, i'm sure.... :pray:
I'm taking phots and will start a thread when i get a little further along.....