62" form and bow build- form done! bow tested !

[kennym]

I gotta get this all done up before April cause I may have a lot more work to do then at my job!

So I've been thinking (usually not good) about this forward handle longbow, and like Thad I just took all the attributes I thought would be good and kind of rolled em together.

Here we go, and PLEASE add your tips, questions , and observations as we go!              

Here is half a bow drawn out for the Nth time!         :D        
         

[kennym]

Once I got the profile I hope to like, I put the template plywood under the paper and with a small screwdriver, mark thru the drawing plan(if you can call it that)..

   

Now to connect the dots , or marks in this case...

I used a piece of 1/16" phenolic to get the curves nice and smooth..

   

To the bandsaw and cut out, leaving plenty, it sands to the mark easily...

Note the centerline is an inch from the end of template,so you can run the router a fuzz past center....

   

To the belt sander and lightly sand so it doesn't dig in and make dips, light touch is good!! Do the inside radius on the idler drum end...

   

[kennym]

Hand sand with a block til it looks and feels good and smooth, no dips or bumps...

 

Hard to bend the phenolic around the curve , hold it, and take a pic, so used the drill to help, about 2" left of the drill is a slight flat spot. Sorry the pic doesn't show it better. Gotta teach Zwickey to take pics!! LOL

More hand sanding on the template fixed it. Bend something around the curves and the bumps and dips will show themselves. They will also show in a bow limb if you don't catch em now!!    

 

Now to cut the form blank pieces, make sure they are wide enough to get the form out of , bigger curves take bigger pieces. This is 12" wide, I like at least 4" to the edge of form.

 

Here I have marked the template on the form pieces so I don't get any screws in the cut and router line. Buuut made a mistake and marked it too close to the one edge, so just moved the screws away from line.....


 

[Kopper1013]

Thanks for the build along Kenny this will be very helpful and informative I'm sure... Can't wait to follow this one

[kennym]

Plywood is always curved, so turn em to help take it out. I had to add a .110 pc of plywood in center that I sanded to thickness to get 1.5" plus just a little, the glass I checked was .010 oversized width.

   

I clamped it to the bench and was surprised to find it was good and flat end to end and corner to corner...

     

     

Ready to glue/screw together.... Remember, no screws where the router will run!!

     

Glued, screwed and tattooed. Bandsawed on waste side of line I marked an A on both pcs to keep everything matching each other...

I also mark the waste side of line to cut, don't even ask why!!      :rolleyes:      

     

Template screwed onto form, and clamped to bench for safety, you have to push down on router to keep bit square with face of form...

     

Here you can see why the inch past center on template, gives the router bearing a place to run so you can get to center. Make sure the template is good and flush at the centerline when you flip to other end...

   

[kennym]

The pattern bit that runs against the template. Carefully adjust so the bearing rides good on the template.

 

After routing and sanding lightly with the block, I used contact cement to put a .030 glass on the form...

 

Planning an 18" riser, I marked the form 9" each way from center. With an 18" pc of ply for a pattern, I found that the riser block will have to be 3 1/8" deep.

 

Marking the pattern for riser back...

 

And marking the belly of riser. I wanted 1.75" total depth on grip, so I made the actual riser 1.5" deep, and with back overlays should put the lams right at the grip low spot...

 


That's all for today!  

[kennym]

Forgot to say, the template is for one half of the bow. Make it an inch past center of your drawing, then mark that inch line all the way around the template. do one end, then flip to other end and screw the center line hole first back in same hole on form. End up with identical limbs on both ends of bow...

[Beau J]

Looks sweet! I really like the curves...BeauJ

[jsweka]

Lookin' good Kenny.  I can't wait to see the first bow off of it.

[bjansen]

Can't wait for this one Kenny   Looks great so far.

[hoo-ray]

Looking in Kenny.  Thanks for doing the build along for the form.    Josh

[kennym]

Thanks guys, I'm a bit worried about how the limbs will come off the deep deflex in riser tho....

If I miss anything, bring it to my attention and I'll try to edit it in there!

[Dmaxshawn]

Oh man I'm really liking the looks of this one here Bud.   with those curves she looks dangerously sexy.  Tuned in for sure.

[Thadbow]

Im liking this...  

[BenBow]

Kenny I use software that I enter the dimensions then it will show how the design will bend. Here are some links to the screen shots. They are too big to show as an image and still be able to see detail so I'm only adding a link.
   

 
   

[BenBow]

With this excel spreadsheet you enter the width, thickness, and distance from the belly and centerline. Then it calculates the bending stress and shows more information than any geek could want. BTW this was designed by Allen Case who is a flight shooter.
I've used this and found that some of my forward handle designs wouldn't work because they had too much deflex/reflex

[kennym]

Thanks Galen, I haven't exceeded what some of the others in production have done, so hopin they will be OK!!

[BenBow]

Going to enjoy seeing this develope

[mwosborn]

Perfect timing Kenny!  I started a form during my evening time this week with a very similar profile - show me the way!

[kennym]

Got the form done today, need some wax now....

Also made the lams and cut out a riser and have it close to being fitted to form.

Will load some pics tonite and tell the rest of the tale!


then on to the bow tomorrow, have Monday off. Hopin for a 62" forward handle about 50# @ 28"!