Pyramid bow layout questions

[Xander]

I'm going to attempt to build my first bow following the "so you want to build a bow" thread, but I'm hoping to style it a little different.

I will be using quartersawn red oak, 3/4" thick.  I am going to go for 68" ntn, 45-48# @28", going to do the laminated reflexed tips, 9" riser and 4.5" grip.  I will back it with brown paper or something else if required.

I am hoping to get it down to 2.25" at the widest, do a palm swell grip and bring the fades down a little bit, unlike the bow in the thread.  I am hoping to lay it out much like the black bow seen here on Kunst Griff site:   http://www.kunst-griff.info/en/others.html

My questions are, what should my riser/fade layout look like for a bow like this?  I know my handle length, my over all riser length, but where should I start and end the fades for this look?  Its hard to see, but it looks like the fades end just above the widest part of the limb.  What radius should I use for the fades?

Also if anyone has better or more clear pictures of a similarly styled bow to help me lay mine out that would be great.

Thanx!  Looking forward to get started!

[4est trekker]

I purposely overbuilt that bow in the thread because folks generally lay out their fades incorrectly on their first bow(s).  You can dress it up, no doubt.  The general rule with fades is, as the bow narrows, it thickens.  It doesn't take much, as a bow doubled in width with double in draw weight.  A bow doubled in thickness will increase 8-fold in draw weight.  

Layout the rise as indicated in the bold note I added to the thread (that is, with an 8" riser instead of 10".)  Then, begin the fade into the limbs from the riser starting at the 2" marks and extending something like 1/4" to 1/2" beyond the 4" marks.   I'm terrible at explaining this, but here's few pics to help illustrate.  The first is from the buildalong bow (overbuilt).  The next two are from a another bow I built with a more traditional layout.  You can see how in the first one the handle is at full thickness at the height of the fade.  In the second and third pictures, the fades begin just slightly before the handle section narrows.

   

   

 

[Xander]

Thank you!  That second pic is more of the layout I'm looking to do.  Im very handy with tools, an ex metrologist and designer in engineering research so understanding beam theory is easy enough for me.  I was just trying to find a little more information and pictures relating to the discussion that immediately followed the finish of the build, regarding this type of layout.  

Also, I got a 6" wide X 8' long, so if I goof up I have more to make another.

So do my dimensions look good?  I have large hands which is why I want a 4.5" handle section, but should I stick with the 8" riser length?

[4est trekker]

Nah, you can elongate the riser.  You could start with a total length of 70" just in case something goes awry, but it's not a biggie.  Your dimensions look just fine.  Best of luck!  

[chachamooby]

Hey xander, i followed 4est's build-along and now do my handles like this. These bows shoot great, good luck, hope this helps. See pictures below.

     

     

   

[4est trekker]

Very nice, A.J.    

[Xander]

Very nice work!  Yes that does help, exactly the type of layout I am looking for.

How thin do you go down to in the handle section?

[chachamooby]

Layout at 1" and it ends up being a little under after sanding. The depth is 1.75" at it's deepest--so I think you'll find the handle pretty large. I also shoot better with a larger handle--even though I like the look of a thinner one. Just make sure you start your slope in the actual board so the handle doesn't flex. So far I haven't had one pop off. Also it helps to make the glued on handle longer than where the fades end. That way you can get a nice transition from both the sides and the belly.It's a lot more shaping but worth the trouble IMO.
Have fun--and 4est is the man for posting that build along. Thanks--AJ

[Xander]

Ok, so I have a layout drawn up and I just want to check with you guys to be sure everything looks good.  I can't resize my pics from my phone, so I will post a link to it.  Hopefully the link work and it doesn't just show up.

All specs are in the drawing, drawing is scaled 1cm=1inch.

What limb thickness should I start with to get 50# @29"?  I'm thinking 17/32" and can tiller down another 1/16 easily if needed. I'm really hoping to get 48# @28" but my father will likely want to shoot it and he has just a little longer draw than me, so I figure design it to his specs and I will just short draw.

 http://i49.photobucket.com/albums/f295/fast14riot/2013-02-03144215_zpse475ba7b.jpg


Thanx for all the help and reassurance

[chachamooby]

That plan looks good to me. The thickness is around 1/2" to get your 50#. It will depend a bit on the board as to the final weight. Go with your plan, it looks good--Just start letting the chips fly and then 2nd do not get impatient when tillering.
It will take hours the first time to do it right--maybe days. It's more important to get a proper tiller on it than hitting the weight. Keep the limbs bending evenly and nicely.  You can do it. Keep us posted.