Primitive Archer

Main Discussion Area => Bows => Topic started by: Slackbunny on January 31, 2012, 07:12:54 pm

Title: What exactly is a pyramid bow?
Post by: Slackbunny on January 31, 2012, 07:12:54 pm
So I can infer from the name that a pyramid bow probably has a triangular cross section, but other than that I don't know much about them. Is it the same or similar to a trapped belly?
Title: Re: What exactly is a pyramid bow?
Post by: Ifrit617 on January 31, 2012, 07:16:19 pm
A pyramid bow is not triangular in cross section... The limbs appear triangular though when looking at the bows back... From the fades it is a straight taper to the tips, with no parallel section existing in the limb...

Jon
Title: Re: What exactly is a pyramid bow?
Post by: Slackbunny on January 31, 2012, 07:19:46 pm
Okay, I get it now. You just start your limb taper right from the fades. Even simpler than I thought. Thanks.
Title: Re: What exactly is a pyramid bow?
Post by: Ifrit617 on January 31, 2012, 07:20:33 pm
No prob.. ;)

Jon
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on January 31, 2012, 07:23:43 pm
It's Egyptian in style.  Made from slave-cut limestone and imbued with otherworldly powers that normal humans can't comprehend.  Alien races are often attributed with the engineering principals, but it was slave labor that made them, ultimately.  Even in the age of the Pharoahs it was The Man keeping us down.

Actually, it refers to the triangular shape of the limb's profile and not the cross section of the limb.  In cross section it would be rectangular (if made from a board opposite sides would be parallel.  But if made from a stave, the back of the bow would be slightly arched from the outside circumferance of the tree).  Pyramid bows taper in width from the widest point just below and above the handle area down to the tips.  Because you are narrowing the limbs consistently from grip to tip the bow limb often remains a consistent thickness from widest point to the tips.  Clear as mud?  Good.  My work here is complete.

Pyramid bows are pretty efficient shooters, fairly easy to make from a board when you don't have a lot of experience with tillering, and work great with lighter target arrows.  The broad part of the limb just seems to beg the maker to indulge in some geometric artistic expression, for some reason.  Something about that otherworldly powers these bows have.  >:D
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on January 31, 2012, 07:24:17 pm
Okay, I get it now. You just start your limb taper right from the fades. Even simpler than I thought. Thanks.

Not quite. The handle needs to extend a little past the start of the fade or you create a break point on the bow. I learned that the hard way. The easy part if that the limb thickness is pretty much the same the length of the limb. Much of the tiller is done on the side of the bow.
Title: Re: What exactly is a pyramid bow?
Post by: Ifrit617 on January 31, 2012, 07:53:46 pm
Can you explain what you mean Bevan? I have always begun the taper on my pyramid bows right from the end of the fades, and have never had a problem, being careful to not go to deep with my rasp i those areas..

Jon
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on January 31, 2012, 08:05:21 pm
If the handle fades into the limb at the red line it causes a stress point that can fail very easily. If the handle fades to the green line area, then the limb does the work.
I made a pyramid bow and did it to the red line. almost 3" at the fades then straight lined to half inch nocks. I tillered it for me and everything was fine. I let a friend draw it and it popped right at the fade. I had some more experienced bow makers look at it and we determined that there was no support. I can post a photo when I get home if the description does not make sense.
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on January 31, 2012, 08:10:18 pm
Yup Bevan, that's just what the aliens told me, too.  They don't bother me so much now that I wear tinfoil boxers.    ::) 

Those gradual fadeouts share the load, so to speak, and prevent the stresses from focusing too narrowly.  Someone also posted recently about how when working the fades they always use the rasp from the limb into the face instead of from the handle down into the fade.  Prevents a hinge from developing in that spot.  Tricks, tips, and work-arounds: that's where this forum really shines!
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on January 31, 2012, 08:13:47 pm
Someone also posted recently about how when working the fades they always use the rasp from the limb into the face instead of from the handle down into the fade.  Prevents a hinge from developing in that spot.

Never really thought about it, but that is what I do as well. As soon as the limb is bending, I put away the rasp and use a cabnet scrapper. Takes a little longer, but I like the control better.
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on January 31, 2012, 08:14:59 pm
Control freak!

I tiller with a spokeshave!  Ride'em wild, who needs a saddle!
Title: Re: What exactly is a pyramid bow?
Post by: Ifrit617 on January 31, 2012, 08:36:00 pm
Thanks for the tip beavan... I'll try it on the next one... I guess my fade always extends a bit onto the limb, since it is hard to get yay immediat transition with hand tools...

Jon
Title: Re: What exactly is a pyramid bow?
Post by: Lone500 on January 31, 2012, 08:53:56 pm
i think ill try this design for my second hickory bow. seems pretty simple.
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on January 31, 2012, 08:58:09 pm
I really like this design. especially if you are using boards. I backed the black walnut one (the one that got broke) with canvas.
Title: Re: What exactly is a pyramid bow?
Post by: Slackbunny on January 31, 2012, 10:09:13 pm
You know I made a pyramid bow once without actually knowing what I was doing, and my fade outs ended right where my taper started, and that is exactly where I had problems when it broke. Nice to know what went wrong.
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on January 31, 2012, 10:16:52 pm
I have made it a 'standard' for me to extend the 'handle fade' (as I call it) 3/4" past where the limb starts. I have not had a failure sense I started that.
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on February 01, 2012, 01:35:17 am
Somehow in tillering I always have limbs that are too stiff close to the handle, so I chase the arc into the fadeouts.  Much better than some of the first efforts where I had to weaken the whole limbs to catch up to the hinge at the fadeouts. 

Slack, give this design another try with your experience and see if it doesn't turn out pretty good!  Just pay proper homage to the aliens and the Pharoahs.
Title: Re: What exactly is a pyramid bow?
Post by: blackhawk on February 01, 2012, 09:16:44 am
A pyramid design with stiff eifell tower taper levers for the last 1/3 or so of your limb makes a faaaaaaaaaaaaaaaast bow. Its prob the simplest design to get a high performance bow.  8)
Title: Re: What exactly is a pyramid bow?
Post by: Rick Wallace on February 01, 2012, 10:22:51 am
Anybody got pics??
 ???
Title: Re: What exactly is a pyramid bow?
Post by: Jude on February 01, 2012, 11:06:40 am
I made one like Blackhawk described for hunting season last fall.  The limbs were about 2" wide at the fades and tapered to about 3/4" at the 2/3 point.  I left the limb a little thicker working into the 'outer fade', for lack of what else to call it, and made the outer 1/3 of the limb about 1/2" wide by 5/8" thick.  It's hickory, around 65" N-N and pulled 48# at 28".  It's probably the fastest bow I've ever knocked out, though I'm not sure how long it will live with the 20" working limbs.  I finished it the day before the season opened, so I was too busy shooting it in to take any pictures.  My measurements are approximate since I don't have the bow here in Afghanistan and I'm working from memory.  I go on R&R in a couple weeks, and will take some pictures then.  I suspect, if it fails, it will be at the transition from working to outer limb, since I think I should have left it a little thicker there.   While it lasts, its a snappy little bow, and flings my poplar hunting arrows pretty hard at the target.  I'd like to see what it does with a lighter arrow though.
Title: Re: What exactly is a pyramid bow?
Post by: Sidewinder on February 01, 2012, 01:11:37 pm
The pyramid design is my favorite. I make most of mine in that fashion. I have mine taper to the last 6-7 inches at around 1/2" to 5/8 and then take it as narrow as I can get it from there. The last 7" is non working. They shoot real good. I think you will like it. 
 The first one I made was from a hickory board. I PM'd Tim Baker and he suggested giving another inch past the fade out before I did my even belly thickness. This was probabley due to the fact that I had a glue on handle buildup and it was insurance that it would'nt pop off. What I have noticed is that most of mine do have about a half inch bufferpast the fades before even thickness begins in the belly. Danny
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on February 01, 2012, 01:46:08 pm
I will try to remember to get the bow out of the rafters when I get home and take some pics to show. Even though it is broken, I kept it.
Title: Re: What exactly is a pyramid bow?
Post by: bubby on February 01, 2012, 05:06:02 pm
here's a front profile pic of one, Bub(http://i623.photobucket.com/albums/tt320/bubncheryl/blade001-8.jpg)
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on February 01, 2012, 05:31:51 pm
Here is the walnut one I made. 68" long. 3" wide at the 'fades'.
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on February 01, 2012, 05:32:51 pm
Here is the 'problem' handle. no support for the limb/handle transition. The circle is where it failed.
Title: Re: What exactly is a pyramid bow?
Post by: bubby on February 01, 2012, 06:15:16 pm
man you basically had no fades at all, on mine i've gone from an 1 1/2" fade to a 2 1/2", i didn't have a failure but seemed more stable,beautiful wood walnut, Bub
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on February 01, 2012, 10:56:16 pm
Bevan, those radically short fade-outs area really visually interesting.  I bet if you were to start it bending about an inch and a half out the limb that bow would have worked just fine!  Dang it anyway.
Title: Re: What exactly is a pyramid bow?
Post by: Bevan R. on February 01, 2012, 11:51:33 pm
Yes JW. I even have gotten some more black walnut to make a version II. That was about the sweetest shooter I have made. Worked fine for my draw, but the gorilla drew it about 3 or 4 inches past my draw. :'(
Lesson learned as they say.
Title: Re: What exactly is a pyramid bow?
Post by: JW_Halverson on February 01, 2012, 11:54:17 pm
Same thing happened to my very first bow.  She seemed indestructable until an idiot let a moron overdraw it. 

Now when I give a kid a bow I make 'em promise that they will never let anyone taller than they are pull the bow, especially an adult!