What is the secret....?

[AKmud]

What is the secret to making smooth arcs on a bow form?  

Today was my first attempt at making a R/D form.  I started with a sheet of 3/4" CDX.  I ripped it in half then screwed/glued the two halves together to get a 1 1/2" thick piece to work with.  I cut it down to 72" then laid out the design.  

I bought a 8' stick of 1/8" x 1 1/2 aluminum to line the surface of the form.  I used this piece to create the curves for the form as well.  I put nails in strategic spots to make the R/D shape with about 3" of deflex (from the back)ending with about 1" of reflex at the tips (forward of the back).  

I took my time and cut out the form with a high quality saber saw leaving the line to dress up with a drum sander on the drill press.  This is where I wasn't very satisfied...

I made sure the table was square with the sander and slowly brought the edge to the line.  I squared it up in a few spots with a hand sanding block and mounted the aluminum strip with countersunk screws.  Standing back looking at the lines, it isn't quite as perfect as I would like.  I notice a very slight flat spot on one of the curves and have tried loosening a couple screws and playing with the strip to get things bending better but I'm not sure I will make any progress without shimming the strip.  

Am I missing any steps here or are there any secrets for making great lines??

[kennym]

Here is the best way I've found, much easier to get smooth flowing lines on a pc of 1/4" as a template than 1.5 or 2" thick.......

 http://kennyscustomarchery.com/Bow_forms.html

Hope this helps some.

[Tom Leemans]

Like Kenny says. Do what you did to make the lines, but on a piece of something like 1/4" hardboard. (masonite or something) Much easier to tweak that until perfect then use that for your guide for the pattern cutting bit.

[AKmud]

Thanks for the info guys.  Kenny I did peruse your site before trying this but I somehow missed the 1/4" pattern....  I might grab a piece and overlay it on my form and try again.  I have some wiggle room since the form is 24" bottom to top.  

Do my dimensions sound about right 3" negative returning to 1" positive over 72" form?

[kennym]

24"?  :eek:    Man, you better have yer wheaties before puttin that in the heatbox!!  :D  

The d/r rate sounds pretty good too.

[AKmud]

Yeah....not really sure what I am doing so I just took a sheet of 3/4" CDX and ripped it in half.  What are typical dimensions of a form?

[kennym]

My 64" d/r requires a 1.5 x 12 x 72 form blank.

I just try to have at least 4" of form in all the dips....

[AKmud]

Thanks Kenny, I think I'll pull some screws and make some modifications.