My first three piece take-down proto-typing!

Started by Apex Predator, June 24, 2010, 09:37:00 AM

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2treks

C.A.Deshler
United States Navy.
1986-1990


"Our greatest fear should not be of failure but of succeeding at things in life that don't really matter."
~ Francis Chan

Apex Predator

I've having one built by a local machinist buddy of mine.
I didn't claw my way to the top of the food chain to eat vegetables!

Dick in Seattle

Looking good!   I'll be real interested in your experience with the bolts and pin setup.  I have the jig for it, but haven't even begun to build up the nerve to try it.   As you know, I opted to play with the hinges first.
Dick in Seattle

"It ain't how well the bow you shoot shoots, it's how well you shoot the bow you shoot."

jess stuart

Looking good so far.  Can't wait to see more.

bjansen

I've been waiting for this one Marty, ever since you posted your intial design thoughts about this take down.  Its looking great.

tommy6

I have to say that your not making this first attempt an easy one. Limbs on the belly introduces a lot of issues that are potentially harder to deal with. Looking at the website of arguably the most famous of the belly sided take downs, Black Widow Bows, especially the pch model shows one limb blot in the center of the pad with 2 pins, one on either side. The grip extends further back than the limb pad, which really looks sweet and allows the riser to be shorter without your hand touching the limb. I have always found it easier to copy a bow and add refinements, than to start from scratch in uncharted territory. Looks good so far!
Dont hesitate, ventilate

Loren Holland

Marty,
I know nothing about take downs, but I applaud your willingness to experiment and share it with us.
In trying to understand why you designed it this way, i get the reduction in the degree of angle on the limb pad to reduce brace height. what about the limb profile now though. does it change to reduce stress in the area that would be the fade if it was a one piece?
Now i think that the reduction from 10 to 6 will give you a better string angle also, or are you changing that with limb profile and length?

Apex Predator

The tighter curve on the limbs will allow me to increase the pre-load on the limbs without going too high on the brace height.  The straighter section of limb will be easier to manipulate the bend on with wedges, if necessary.
I didn't claw my way to the top of the food chain to eat vegetables!

Kevin Breaux

Something new to ponder... you are looking for a lower brace with (higher) load in the first 4-6" of draw... Have you concidered redesigning the limb and making it static recurve limbs?

Apex Predator

I'm gonna get the longbow figured out first.  I won't know any more until I get that first set of limbs on her.
I didn't claw my way to the top of the food chain to eat vegetables!

mater

I made one of those once, that looked like the staighter of the two. With the forward riser, that will point well. Mine shot very well. I just couldnt get used to the look and sold it. Mine was longer than that, maybe 62" I cant remember for sure. There very stable with that big riser.   Mark

Lamey

looking forward to how this unfolds,  your posts are always very informative.

GREG IN MALAD

Marty,
After looking at the limb profiles on page one of this thread, I think you will have string slap problems on the back of the limb. This is my take-down hybrid, it is 1.5" wide x 64" long and uses .002" taper per inch, with a 16" riser and 8" wedges and 10 degree limb pads. My first 2 prototypes used a tighter radius at the tip and both had string slap.
 
I didnt miss, thats right where I was aiming

GREG IN MALAD


If you are intrested in the numbers, this bow will shoot 9 gpp @ 28" in the 190 fps range with a solid anchor, hold, then release. And in the 200 fps range with a pull through flight shooter release.By the way, this is my fishing bow, thats why its wearing a no-glove.
I didnt miss, thats right where I was aiming

Apex Predator

Great looking bow Greg.  My initial plan is in motion Greg, so I will have to modify if mine has string slap.  I do want to avoid that.

Had a little time yesterday and this morning to work on my form.  Plywood doesn't measure what it's supposed to, so I bought a sheet of MDF.  Three 1/2" pieces measure the 1 1/2" width I need.  I figure if I put a finish on it, the thing should hold up well enough.  Lot's of forms made out of this stuff.  We'll see!

This form is longer by 2" than I plan on needing for usable limb.  I've found that the last inch or so always needs to be cropped due to trouble getting good glue lines at the very end.

 

 
I didn't claw my way to the top of the food chain to eat vegetables!

GREG IN MALAD

Marty,
I use 1/8" or 1/4" masonite in the middle of my plywood forms to get the correct width.
I didnt miss, thats right where I was aiming

Over&Under

Marty
As with all your bows, I am impressed once again.  Great looking design and as it has been said, looks as though you put alot of thought into this.

Good luck with the rest of the process and looking forward to the finished product.
"Elk (add hogs to the list) are not hard to hit....they're just easy to miss"          :)
TGMM

HATCHCHASER

I love that riser design.  I just have trouble with short bows.  I would like to see that type of riser in a 64" or 66" bow.  I think that riser coupled with a mild r/d style longbow limb in longer lengths would be the ultimate in shootability for a long draw guy like me.  Can't wait to see how it turns out.
It's not the arrival, it's the journey.

Swissbow

Marty, can't wait to see your bow when it's finished. I'm sure it's going to look fantastic. You make me wanting to try a take down myself.

BTW Greg your bow is absolutely awesome.

----------
Andy

Apex Predator

I got my form finished, my wedges built, and my lams cut to size and prepped.  I'm gonna glue up one limb in the am.  My drilling jig should be finished tomorrow.

Here is the wedge on top of one piece of black glass and two edge grain red elm lams.  Another piece of black glass goes on top, as seen in the other photos.  Each red elm lam is tapered .015 each, for a total of .003 limb taper.  My total lam stack is .316, which is a little more than most recommended, but I tend to need a little more than most others.  Besides I had them on hand already ground.  It's a W.A.G. at this point anyway.



With a little hand pressure the lams draw down nice and tight.  I think the glue up will go very smoothly!





I didn't claw my way to the top of the food chain to eat vegetables!


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