Post by: tsriberio on February 25, 2020, 12:01:38 PM
I have a whole heap of parallel hickory laminations that were gifted to me by a friend. If I can get away with just buying fiberglass and riser material for awhile that would be great.
Are parallel limbs fine for bow building? I imagine some designs work and some don't. If so, please give me some clues!
Thanks in advance.
Post by: Flem on February 25, 2020, 12:20:15 PM
Post by: kennym on February 25, 2020, 12:40:19 PM
My Fhlb has .001 taper and could maybe be built parallel. Haven't tried that yet... :)
Post by: tsriberio on February 25, 2020, 01:02:03 PM
My thought on it is you have to have some taper in the limbs for it to bend properly. Like Flem said, if the bow is wide enough, you could have the taper on the edges of limbs. You will notice the narrow longbows have much more taper than say a recurve with 1.75" wide limbs. Some guys put as much as .006" per inch in them.
My Fhlb has .001 taper and could maybe be built parallel. Haven't tried that yet... :)
So, I imagine that a bow could achieve proper bending by tapering the limb width as opposed to back-belly width, but that with narrow longbows lack the starting width to achieve a fast enough limb-width taper rate? Is that what you are getting at?
Post by: kennym on February 25, 2020, 01:19:40 PM
Post by: Crooked Stic on February 25, 2020, 02:37:41 PM
Post by: ztontonz on February 25, 2020, 03:07:03 PM
I did my first D/R bow with all parallel lamination. It was pretty smooth and fast, but I really hated the hand shock!
Like said above working with width taper might be a good way to go.
Just my two cents...
Post by: Forwardhandle on February 25, 2020, 03:27:22 PM
Post by: Bowjunkie on February 26, 2020, 03:53:01 AM
Another option for you is to send your lams out to be ground to the exact thickness and taper you want. I did that for a bunch of bows until I got set up to do it myself.
Post by: Crooked Stic on February 26, 2020, 07:40:12 AM
I vary the taper depending on other design specs, but would never build a bow with all parallel lams.
I am curious why you would never build a bow with all parallel lams.
Post by: kennym on February 26, 2020, 09:13:47 AM
I vary the taper depending on other design specs, but would never build a bow with all parallel lams.
I am curious why you would never build a bow with all parallel lams.
Mostly because I don't like wide limbs and/or hingey bows... :goldtooth:
Post by: Buemaker on February 26, 2020, 10:43:49 AM
He has made many over the years.
Post by: tsriberio on February 26, 2020, 10:45:16 AM
Kirk says that in a very light weight recurve all parallel or just .001 taper is advisable. It is good for vertical, sidewise stability.
He has made many over the years.
I am guessing that by "lightweight" you mean draw weight?
Post by: Buemaker on February 26, 2020, 10:48:02 AM
Post by: Crooked Stic on February 26, 2020, 11:26:23 AM
Post by: tsriberio on February 26, 2020, 11:42:20 AM
I have made several recurves with all parallel lams. You can use two tapers and reverse one =parallel. Binghams pronounced longbow is parallel by use a reversed taper. Built a few of them years ago with normal limb width. I can figure how all parallel could be more apt to hinge??Yeah, I definitely don't argue Kenny's expertise, but I am having a hard time conceptualizing a hinge in a bow that should be bending evenly due to same limb thickness.
I could definitely see how it wouldn't tiller quite right to a R/D design, where you want the outer parts to flex more than the inner. But I would think a straight limbed bow would hold a decent circular tiller. Now I know circular tiller isn't the most efficient design but I would think it would work :dunno:
Post by: kennym on February 26, 2020, 11:47:00 AM
Post by: tsriberio on February 26, 2020, 11:49:00 AM
I vary the taper depending on other design specs, but would never build a bow with all parallel lams.
Another option for you is to send your lams out to be ground to the exact thickness and taper you want. I did that for a bunch of bows until I got set up to do it myself.
Living in Alaska I am not afforded this luxury, would be cheaper to just order new lams. My only luck would be to find someone in town with a drum sander.... but even then the butt thickness on most of my lams is too thin.
Living in the greatest state for an outdoorsman has it's drawbacks, but I would gladly pay them twice again.
Post by: jess stuart on February 26, 2020, 07:08:00 PM
Assenhiemer bows used all parallels and they were and are still very highly regarded. I feel depending upon the design either tapers or paralles will work just fine.
I used to use .003 in my recurves but now mostly .0015 or .001 total taper.
Post by: Flem on February 26, 2020, 07:55:16 PM
"Here is another option, if you have lots of time and patience. It's a shooting board/sled I made for truing up lams. If you mic homemade or store bought lams, you will probably find they are slightly inconsistent in taper rate. Not a big deal unless you are OCD like me.
It's a simple MDF box with angled runners along the side that correspond to the taper rate. I use it with a sanding block or low angle plane that rides on the runners. The bed is 3/4 MDF with sandpaper glued on. The thickness gets adjusted by shimming under the bed. I use it after I have ground my tapered lams, but you could use it with parallel strips to get your taper. It's not fast, but it's dead on accurate."
Post by: tsriberio on February 26, 2020, 07:59:57 PM
Groundhog Day!
"Here is another option, if you have lots of time and patience. It's a shooting board/sled I made for truing up lams. If you mic homemade or store bought lams, you will probably find they are slightly inconsistent in taper rate. Not a big deal unless you are OCD like me.
It's a simple MDF box with angled runners along the side that correspond to the taper rate. I use it with a sanding block or low angle plane that rides on the runners. The bed is 3/4 MDF with sandpaper glued on. The thickness gets adjusted by shimming under the bed. I use it after I have ground my tapered lams, but you could use it with parallel strips to get your taper. It's not fast, but it's dead on accurate.""
How do you get your runners to the appropriate taper?
Post by: tsriberio on February 26, 2020, 08:04:31 PM
Post by: Holm-Made on March 07, 2020, 12:51:14 AM
Post by: Crooked Stic on March 07, 2020, 07:36:23 AM
Another advantage to using tapered cores In your bows is it takes stress off your riser fade outs. I also like the looks of a longbow limb that bends more in the outer portion of the limb, rather then just being “straight”. I typically use .002 total in recurves and .003-.004 total in longbows.How does more taper have less stress on your fades??
Post by: Flem on March 07, 2020, 09:10:21 AM
Post by: Crooked Stic on March 07, 2020, 05:10:33 PM
You put them in upside down :smileystooges:put the tapered side down ?? :laughing: :laughing:
Post by: Flem on March 07, 2020, 05:33:20 PM
Post by: monterey on March 07, 2020, 07:57:48 PM
Then do the same thing with a lam with 003 taper. It might break at the bench as well but it's going to bend a whole lot further.
If you're not tired of this experiment, take another piece of parallel and side taper it in straight lines to the tip with the tip being a sharp point and do the same bend. That would represent a pyramid bow.
Post by: kennym on March 07, 2020, 08:05:26 PM
That's, not all taper or parallel completely either, also how you do fades and the bow design. :thumbsup:
Post by: tsriberio on March 07, 2020, 08:21:18 PM
Post by: kennym on March 07, 2020, 08:47:56 PM
Post by: Forwardhandle on March 07, 2020, 08:52:38 PM
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Post by: Crooked Stic on March 08, 2020, 09:02:18 AM
Post by: Forwardhandle on March 08, 2020, 10:13:50 AM
Post by: Flem on March 08, 2020, 12:11:54 PM
So if you plan on building a reflex/deflex, recurve, or other prestressed limb type bow, a tapered lamination becomes more critical. Does not necessarily matter how you taper it, you just need to reduce the bending stress at the distal end of the beam. But it does make sense to taper for thickness rather than width. Given two limbs with the same physical mass, the one with a deeper profile relative to the bending axis will be stronger, but less elastic than the wider, but thinner limb.
Post by: Shredd on March 08, 2020, 01:16:06 PM
You may be able to cheat the general rule of adding tapers by adding about 3" to the fades on your riser and making them very lean and then being strategic with your radius's in the limbs to take up the work of what a taper would do... It could work or be a total flop... Just would have to experiment with it...
Most of my opinion here is based on my experience with R/D style bows....
Post by: monterey on March 08, 2020, 10:07:32 PM
My way of looking at it is that the thicker portion of the lam at the fade is not to strengthen the fade. It's that the gradual reduction in thickness (strength) proceeding out the limb decreases the ability of the limb to over stress the fade. Of course the nature of the width taper plays a big part too.
The glass in our bows can hide and protect against many design shortcomings. Maybe our experienced selfbow and trilam builders can comment on our discussion?
Post by: Shredd on March 08, 2020, 11:49:25 PM
I think it is a good point to get the Self Bow Guys involved... They are the masters... Their bend has to be right or it's history...
Post by: Crooked Stic on March 09, 2020, 06:30:21 AM
Post by: Forwardhandle on March 09, 2020, 06:57:05 AM
Post by: 4 point on March 09, 2020, 08:56:57 AM
Post by: Crooked Stic on March 09, 2020, 03:29:53 PM