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Main Boards => The Bowyer's Bench => Topic started by: Djoseph on September 12, 2016, 04:07:00 AM
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Hello I have been visiting
Here for sometime and decided to register....this is my first post...
For some months I have been on the brink of making my first f.g longbow but it's like standing on the edge of a pool and wondering how cold will the water be before diving in!
I have with me a pair each of .03" and .04 fiberglass and want to make a Hill style longbow of about 50#@28" for myself but I cannot afford to fail as I cannot buy f.g and smoothon again as it's too expensive ...
Please give me a true design to ensure success barring any mistakes in construction which will be my responsibility to avoid.
I want a 66" ntn 50#@28" hill style preferably with about 3/4" of reflex after being shot in....
Thanks in advance for your help...
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You will want to be certain that the smooth on has not aged beyond it's shelf life, which is about six months. Some builders have had problems with it when it has aged out.
I build ASLs, but not true Hill style so I'm going to avoid giving you a formula that might not work for the bow you have in mind.
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Thanks for your reply....however I always assumed after reading all I could (correct me if I'm wrong)the biggest difference between the ASL longbow and a hill is that the width profile, the handle/grip shape and riser Length differs.... View moreover hills are not made with power lams but may have a small tip wedge and tip overlay but only on mordern hills off course!!...
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Well, to split a hair, Hill himself coined the term ASL and applied it to his style of bow. The term ASL is popularly applied to all of the flat, reflexed and string follow bows In longer lengths. I call mine ASL, but not Hill because there are differences.
Tell me what width you wish to build, length of riser, etc., All the details and we can try to come up with an estimate of what formula you need.
Maybe some of the true Hill builders will jump in.
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Thanks Monterey. I think for me a 16" riser with 1-1/4" wide at upto 2" past the fades then a straight taper to 1/2" at nocks. Length 66" ntn, 50 to 55#@28" would make me very happy! .
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Ok, I'm going to play around with that and see what comes up.
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Hey man I really appreciate your help....Thanks.
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Monterey I would be happy to have the stack height for a 50 to 55# bow with the other Specs I mentioned above....anything else will do too as long as the bow turns out at the draw weight I want and its 66" ntn with a 16" riser fade to fade....
I am still waiting for some help with my longbow hill style or ASL.......
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Sorry I haven't gotten to this. My internet has been mostly off for a few days and on top of that my desktop is refusing to boot up. I'll get it done though.
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Thanks Monterey I hope your computer works soon I can't wait to start on my bow....
If you are looking for a recipe, I'd suggest you post the particulars of the type of bow you would like to build and request specific design parameters. This site is home to some tremendous expertise residing in members with incredibly generous spirit.
Guys where are all those good people gone I'm waiting for some help with my bow...I need to be successful as I'm not able to purchase the materials I require to build another as I'm retired... If I had a proven design it will then be up to me to get it done right...Thanks for your help...
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I use a 16'' riser,4 x .001 tapers and a wood stack of .390 and 2 x .040 glass should give around 50# at 28'' and 66 ntn. This bow is 1.125' wide at fades narrowing to .5'' at nocks.Hope this helps.'
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Hello bigbob thanks for you reply...i have a few questions...
1. does the .390 mean only the wood stack and does not include the glass.
2. And is the specs you gave for a 3/4" reflex or straight bow...
3. Does the width taper from fade to nocks go in a straight line
Thanks...
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.390 is just wood stack,2 x .040 glass extra, it is a straight laid bow which might adopt .25 to .5'' string follow.The taper is straight from fades to nock groove.
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If you really want the reflex it would have to be incorporated into design of form.Personally I prefer the straight laid design.
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Thanks Bob for clearing up my doubts...is there any reason to prefer a straight vs a reflexed design...
I know it's easier to build.... Does the reflexed profile add a lot of performance compared to the straight or is it just a little?
Thanks for your patience
Dan
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it would depend on the amount of reflex naturally, but as it adds an element of preload it could be a little snappier on the shot. however i don't have any chrono data to verify this.I just prefer the simplicity of the straight laid bow.Unless you get into radical designs [where there is always a trade off] or use exotic materials such as foam or carbon,then the difference is generally minor .The flat laid could be argued as being more stable too.
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Thanks Bob for clearing up that....to make a flat laid bow is definately easier...maybe I should make mine like that since I could use just a flat beam without having to do any shaping of the form etc...
Will Using cycle inner tubes be good enough? To get good adhesion?...I have a hose and end caps...but I wonder if could tie the hose down on top of the lam and riser and inflate it slowly and make sure the lams don't slip etc Wii that work? Or should I just use cycle tube strip method??
Thanks for your patience with my questions....
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I'm coming up with a total stack of .410 for a flat design and .397 for a reflex design.
To reiterate:
66" NTN
16" riser
1.250 width at the fades
.5 at the nocks
Total of .003 thickness taper
The thickness of the stack is measured at the thickest point. IOW, use the thick end of your tapers to calculate stack. If you have to shorten you tapers, shorten at the thin end.
I'll try to get more for you when my internet is back up. Desktop is now running but I need a new modem.
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Hello Monterey thanks for your reply. I hope you get your internet running soon...☺
For those specs is the reflex 3/4"
And one more question if make the fades 1-1/8" wide
What will the changes be everything else the same including the 3/4" reflex and the changes for a flat laid bow? I hope my question is clear!!
Thanks for your patience
Dan
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Just consulted my grubby and tatty notes and have to agree, Monterey.. I make it .4oo for my design with previous specs for 50#. Not advisable to rely on memory [or lack thereof] for stacks!
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Guys does that mean the wood stack should be about .32 to .33" when using the .04 glass that I have
For a straight laid bow?
Thanks for your help.
Dan
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No!. the stacks given are wood [.40 etc,]only plus 2 x .040 glass
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Thanks Bob that's clear now.....
So if I go with your plan the lay out would be as follows
.04 glass
4 × .100 lams tapered .001"/in each
16" riser
.04 glass
66" ntn, 1-1/8" at fades tapering to 1/2" at nocks
Without tip wedges.
Should I make the btm limb 1" shorter or keep both limbs the same length?
Thanks for your help
Dan
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The stacks I suggested were total and include the glass.
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Hello Monterey, got your internet running again? I certainly hope so!
So the stack you gave includes the .04 glass too..ok
But that's for 1.25" width at fades, for 1-1/8" what will the stack be for straight and 3/4" reflexed?
Thanks for your patience, after clarifying this I should be able to decide what measurements I would like to go with...
Dan
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i suggest go with monterey. my notes say .390 stack [wood only] of 3 x .001 tapers plus one parallel using given measurements of bow, would give 55# @ 28'' and 66 ntn This is straight laid only.
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Bob I apologise for my confusion but I don't understand what you mean by
" my notes say .390 stack [wood only] of 3 x .001 tapers plus one parallel using given measurements of bow, would give 55# @ 28'' and 66 ntn This is straight laid only."
Are you saying that for 1.25" fades to 1/2" nocks straight laid bow with 16" riser the wood stack is .390" and using .003"/ inch taper?
Please clarify this for me....thanks for your patience with my questions....
Dan
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Ok, I have got all my tools up and running and done some final calculations.
Here is what I come up with:
All 66" NTN
16" riser
these are total stack including glass measured at the thickest (butt) end of the laminations.
55# bow with reflex at 1.25 inch wide = total stack of .425
55# bow flat at 1.25 inch wide = total stack of .438
55# bow reflex at 1.125 inch wide = total stack of .438
55# bow flat at 1.125 inch wide = total stack of .451
To make any of the above a 50# bow, reduce the applicable stack by .014
While Bob's numbers differ somewhat from mine, don't discount them entirely. Think it through.
As you can see by the .014 figure to reduce 5# of weight, it does not take very much to effect the strength of the limb.
Choice of wood cores may have some effect but contrary to the anecdotal observations of many archers and even bowyers, I don't think you will find much difference in the draw weights of various woods. Heavier core woods may result in slightly slower shooting bows, but not by very much.
What is your source of instructions on the actual build?
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Hello Monterey thank you very much for your valuable input and time. It's nice that you sorted out your com and internet problems..,
I don't discount Bigbobs input it's just that I was confused a bit by his reply between the stack for the different widths and between flat and reflexed but now you have answered me in a very clear fashion
Thanks once again....
I have been looking at some build alongs here and I got to go on that....any advice you give me is most welcome.
The specs you gave I assume from your previous reply is for .003"/in right?
Dan
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Yes, .003 taper.
Don't be surprised if you come up a bit off these predicted weights, but it shouldn't be too far off.
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Thanks Monterey, I'll give this some thought before I commit to building either to your or Bob's specs.
After that I want to build a mild deflex/reflex bow with my .03 glass about 35 to 40#@28" will do.
Regards, Dan.