Primitive Archer

Main Discussion Area => Bows => Topic started by: TBod on September 18, 2009, 03:50:24 pm

Title: Pyramid bow
Post by: TBod on September 18, 2009, 03:50:24 pm
Here's my second attempt at a pyramid or close to pyramid bow. The first broke.. It's 63" ntn 40# 28". It's from Maple (Swedish). Stringfollow is low maybe 1,5" and overnight 0,5". This particular piece is not very dense I guess it's about 45 SG, or under average at lest.

The really cool thing is that unbraced it has a serious twist and when drawn it sort of untwist. I usually get the opposite.. I tried to follow the grain when roughing out,and hence the twist when unbraced.

Pic 2 The back is covered with drying cracks. I put a layer of TB3 mixed with water on the back. The cracks closed and push out a drop a glue. Looks funny!

Pic 3 It's not really a selfbow, more of a laminate bow by accident :D. One big piece and a tiny piece of wood glued on the belly since I as always are a bit rough roughing out..

It feels really powerful shooting. But I am an extreme beginner at shooting..

Pic 1 How about that tiller, is it correct for a pyramid bow?

Thanks for looking!

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Title: Re: Pyramid bow
Post by: Kent D. on September 18, 2009, 04:40:17 pm
I like it.  Looks great.
Title: Re: Pyramid bow
Post by: Josh on September 18, 2009, 05:02:31 pm
Good looking bow man!  I think I would actually flip the bow over and use the bottom as the top and the top as the bottom because the bottom limb looks to be bending more.  Just a personal preference though...  Tiller looks great!   Good Work!   :)  -josh
Title: Re: Pyramid bow
Post by: TBod on September 18, 2009, 05:13:21 pm
Yeah! I agree on the bottom limb. Thats the one with natural reflex, so it should be better for upper limb.

On the other hand it's close to centreshoot now and I like it. So to switch sides I'd have to fix the string alignment pretty serious..

I also try to shoot switching hands holding the bow.  When I hold the bow with my right hand the bottom is up. Haven't really decide which hand works best either.

Thanks!
Title: Re: Pyramid bow
Post by: Josh on September 18, 2009, 05:20:41 pm
you need to find your dominant eye for that...

pick an object like 10 yards away and point at it with both eyes open. 
close one eye at a time and whichever eye makes your finger on the object is your dominant eye.
you wanna hold your bow in the opposite hand and use your dominant hand to draw the arrow to your nocking point (mine is beneath my cheekbone)
  -hope this helps.     :)  josh
Title: Re: Pyramid bow
Post by: Del the cat on September 18, 2009, 06:04:45 pm
Tiller looks good to me...dunno quite how a pyramid tiller should look...
I like an arc of a circle, it looks like if the tips bent a tad more you'd almost have a semi circle,(ignoring the handle of course) which is how I'd guess a pyrimid should go with every bit of the limb working?
Del
Title: Re: Pyramid bow
Post by: NTD on September 18, 2009, 06:32:40 pm
Looks good to these untrained eyes.  I've wanted to play with some pyramid designs but I'm still lost as to how the tiller should look and whether or not they should bend in the hande ???

Nice bow.

Nate Danforth
Title: Re: Pyramid bow
Post by: Del the cat on September 19, 2009, 03:41:56 am
Looks good to these untrained eyes.  I've wanted to play with some pyramid designs but I'm still lost as to how the tiller should look and whether or not they should bend in the hande ???

Nice bow.

Nate Danforth
I don't think one can reasonably expect a pyramid bow to bend in the handle as it is so much narrower than the base of the limb, the change in cross section would make for a huge concentration of stress.
Just my catly guess.
Del
Title: Re: Pyramid bow
Post by: NTD on September 19, 2009, 03:56:13 am
Thanks Del, I've thought I've read some stuff about them bending enough to feel it in the handle and then other places saying no bend.  Thanks for the clarification and sorry bout the hijack.

Nate Danforth
Title: Re: Pyramid bow
Post by: TBod on September 19, 2009, 04:26:41 am
If the tips were bending more, there be a problem with string angle and stack maybe?

Maybe not on my bow but it's longer than the usual for a pyramid bow.

I'll try that dominate eye thing. But I am gonna continue shooting with both hands. I got my TBB4 yesterday and it was a chapter on shooting there, good stuff I missed that about about the other ones.

Thanks!
Title: Re: Pyramid bow
Post by: radius on September 19, 2009, 02:34:43 pm
this one is tillered pretty good, man...

i like the dots all over the back, can you put up a clearer pic of that, please?

keep at it
Title: Re: Pyramid bow
Post by: Josh on September 19, 2009, 03:19:32 pm
if you can learn to shoot with both hands consistently I think that would be awesome!!! I am left handed and when I first started shooting I tried to shoot both ways and since that time I have progressed to shooting all left handed  (with the bow in my right hand)   I really wish I would stay consistent with shooting right handed cause I can't shoot a right handed bow anymore!!!   So if you can learn both and be good both ways I say go for it!!!!!    :)  -josh
Title: Re: Pyramid bow
Post by: El Destructo on September 19, 2009, 03:59:47 pm
TBod....looks nice...I like the looks of the Natural Back of some Maples with the little Dimples in it....gives the Bow some Character! Also I am with Josh....flip the Bow....the Top Limb is Stiffer....good Job

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Title: Re: Pyramid bow
Post by: TBod on September 19, 2009, 04:22:48 pm
Ok here some more pics. Can't get it clearer than that..

The bow flipped. Maybe stiffer maybe not..

Thanks!

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Title: Re: Pyramid bow
Post by: El Destructo on September 19, 2009, 05:08:04 pm
Looks Better to Me.....nice job
Title: Re: Pyramid bow
Post by: bootboy on September 19, 2009, 06:05:55 pm
that method is really useful for tillering deffinately however keeping in mind that to make it work properly you'll need to make the lines on the photo to the oval you're drawing or it will throw your tiller off badly.
Title: Re: Pyramid bow
Post by: El Destructo on September 19, 2009, 06:42:17 pm
Just gives you a good visual baseline to go by....just another tool to use....thats all
Title: Re: Pyramid bow
Post by: TBod on September 19, 2009, 08:10:03 pm
It's a great tool!
It would be even better if there was a way to tilt the picture if one is not holding the bow perfectly vertical.
It would also be cool if you could superimpose one over another.

Here´s more pics.  Flipped (short sleeve shirt) normal (long sleeve shirt) that one should be tilted clockwise a tiny bit. They look equally strong to me, but they bend in different ways.

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Title: Re: Pyramid bow
Post by: El Destructo on September 19, 2009, 08:33:31 pm
There is...you can do it with Photoshop...or HP Photosmart Premier....and I am sure others that have a Rotate Picture...in the Edit Picture Window....that is what I do to straighten them up....it lets you straighten in 1 degree increments
Title: Re: Pyramid bow
Post by: TBod on September 20, 2009, 02:28:21 pm
I found GIMP2.6 it worked in that one two. Free download.

Thanks!
Title: Re: Pyramid bow
Post by: El Destructo on September 20, 2009, 03:31:06 pm
Yeah...but I had all kinds of Problems with that one using XP....had all kinds of Trouble and had to D/L Fixes and Patches ...
Title: Re: Pyramid bow
Post by: OldBow on September 20, 2009, 08:24:36 pm
Great job and bookmarked for Sept Self Bow of the Month fun.
Title: Re: Pyramid bow
Post by: TBod on September 21, 2009, 05:05:39 am
Yeah...but I had all kinds of Problems with that one using XP....had all kinds of Trouble and had to D/L Fixes and Patches ...

The ellipse was a bit annoying in the GIMP, but I draw the ellipse in paint instead. I like the name of the program and you can turn the pic in 0,10 degree steps or (increments?)

I saw you had a webpage, my computer can't find it. Closed?
Title: Re: Pyramid bow
Post by: GregB on September 21, 2009, 08:10:37 am
Very good looking bow! The tiller looks pretty close to balanced between the two limbs...I'd let how the string tracks across the handle come into play on selecting the top limb. If you're not willing to tweak the tips over in the event of swapping the top limb, you may be better to stay with the original top limb selection from an arrow flight standpoint. :)
Title: Re: Pyramid bow
Post by: Pappy on September 21, 2009, 08:56:45 am
Nice job,looks good to me, What Greg said on the top limb.  :) That should be a nice shooter. :)
   Pappy
Title: Re: Pyramid bow
Post by: TBod on September 21, 2009, 04:43:00 pm
Yes I am with you there guys it's close call betwen the limbs in my eyes to.

Thanks!
Title: Re: Pyramid bow
Post by: medicinewheel on September 21, 2009, 07:47:57 pm
May I !?  ;D ;D ;D

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Title: Re: Pyramid bow
Post by: Pappy on September 22, 2009, 05:19:50 am
Very well done,looks good to me,now go shoot it. :)
   Pappy
Title: Re: Pyramid bow
Post by: GregB on September 22, 2009, 08:12:22 am
From the last pic it does look like the top limb is stiffer...there is still the question of string alignment with the handle. Isn't it almost center-shot with the stiffer limb for the top?

Options:
...reverse limbs and tweak with heat to realign the string with the handle
...weaken the top limb through removing wood, will lose draw weight this way
...cut an inch or so off the bottom limb to stiffen it up some, may gain a pound or two of draw weight
...heat treat the bottom limb ONLY, to stiffen it up? potential slight draw weight increase...haven't ever tried it on only one limb, may not make enough difference to even it up
...if it shoots good, leave it alone and shoot it as is
Title: Re: Pyramid bow
Post by: smokeu on September 22, 2009, 10:19:08 am
Good Job Buddy!!! NIce work.

Mike
Title: Re: Pyramid bow
Post by: TBod on September 22, 2009, 03:33:42 pm
Thanks for the response!

It's intersting and educational.

I allready tempered the bottom limb exclusive in the midlimb area to make it stiffer. It gave some effect. I've done that before just temper one limb in a specific area.

I tempered both limbs twice earlier in the tiller process.

The bow weighs 17,8 ounce, according to the Steve Gardner Mass principle in TBB4 it should weigh 17,5 ounce (if i did the calculation right). I'm happy with that!
I checked some of my earlier bows and they are about 5 ounce or more to heavy for the Mas principle..

This two pictures are best for comparing the limbs I think (lots of pics..). I tilted one to fit better with ellipse.
It's probably better to flip the bow, because you should have the more reflexed limb as upper.
I'm not gonna do that though, since the centershoot etc. And they look pretty close in strength.

Pics: first normal, second flipped



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Title: Re: Pyramid bow
Post by: VenomBOWslinger on September 22, 2009, 03:48:52 pm
Great looking Bow with losta of Character Im actually better at shooting than Im at making them...lol  Needless to say u do fine work and the tillering is damn close to almost perfect! 

CHEERS!! ;)
Title: Re: Pyramid bow
Post by: George Tsoukalas on September 22, 2009, 08:55:57 pm
Looks great! Have fun shooting. Jawge