3 Piece Take-Down questions

[cunruhshoot]

I just finished my first 3 piece take-down and I really enjoyed building it. It is 68" ntn and 60# @ 28". I ordered lams from Bingham. Here is my question(s).

1. Is it necessary to build the limbs using a reverse taper or can I build the same as I would a one piece longbow?

2. They say I can use the Bingham form that I built to build multiple length limbs...How does work? The Bingham plans don't define the process.

3. They (Bingham) offer a 15" riser template and a 17" riser template  - I used the 17"  - At what point would you switch to the 15"?

Thanks for the help?

[delongbows]

1. Can't really help with this...I've never built any with reverse tapers?
2. All you need to do is drill your form for the stop pin in 1" increments. Usually 68-66, 64-62, etc.
3. I'm not sure about bingham's design, but with my design I run 16" riser down to 60" then I drop down to 15" and adjust my wedge length as needed.

Hopefully someone that uses bingham's design will chime in and give some specifics.

[Crooked Stic]

You can shorten or lengthen you limbs by 1 in either way by moving the dowell pin in the form. I would think either length riser would work ok.

[beachbowhunter]

Cameron,
My PM is right in line with what Dave said. You shorten from the butt end. I try never to shorten from the string groove end.

[kennym]

About the reverse taper, I know guys who build with all parallels in that design. With the same forward taper and reverse taper, you have a parallel limb.

[Troy D. Breeding]

When I started building three piece bows many years ago I was told to use a forward and reverse taper. After dropping the reverse taper and adding another parallel my bows shoot smoother. All it did was shift the bend in the limbs slightly towards the tips.

[Buemaker]

If I do not remember wrong Bingham says to use a reverse taper on the bow form (not in the bow limb) to even out  the taper towards the tip. Most people don't do it and there was a post some time ago that someone had called Bingham and they said you did not have to do it. Bue--.

[Mad Max]

Originally posted by Buemaker:
If I do not remember wrong Bingham says to use a reverse taper on the bow form (not in the bow limb) to even out  the taper towards the tip. Most people don't do it and there was a post some time ago that someone had called Bingham and they said you did not have to do it. Bue--.

X2 on the reverse taper goes on the form
I bought the plans for the one piece recurve
THE REVERSE TAPER ON THE FORM MAKES A 80# BOW AND A 30# BOW THE SAME PROFILE BECAUSE OF THE STACK DIFFERENCE .
IF YOU DRAW (NOT DRAW AS IN SHOOT, DRAW AS IN CAD DESIGN)BOTH THE 80 AND 30 ON A COMPUTER YOU WOULD SEE THE DIFFERENCE.

[M P Clark]

I've called bingham about similar questions:

Bingham's responses:

Shortening the limb 2 inches (1 inch per limb) will increase draw weight #7.

Shortening the riser to 15" has very little affect on draw weight and they did not consider it in choosing their limb stack.

They instruct the stack to be Glass, 0.002 taper, parallel, limb wedge, reverse 0.002 taper, glass.

They said this gave them the best performance (but didn't go into details on how much or what they were considering as performance)

They also stated that you could use all parallels if you wanted, the instructed stack was their suggestion.

I just finished a pronounced T/D with a 14.5" riser and overall 60.5" ntn.  

(The length was a goof, was going for a 15" riser and overall of 62": didn't measure the riser twice and cut it 1/2 to short and moved the string grooves down a little once I knew the riser was short to get it closer to 60")  

Stack was 0.04 glass, 0.03 veneer, 0.1 taper, limb wedge, .09 reverse taper, 0.03 veneer, 0.04 glass.  Draws #48 @ 28" and stacks at 29.5 inches.

Veneers were spliced osage orange and smokewood (Thanks Troy) with action bamboo tapers (again Thanks).  Haven't chrono the bow but sends my 438 grain arrow hard.

Some hand shock that is only really noticeable when gripping the bow tight / hard.

Made a 12 strand ultra cam endless loop string with padded loops, small wool puff silencers, and the bow is real quite.

Hope this helps

Oh, Riser is osage orange and black palm.  I'll post some pics in a bit if anyone is interested.

[M P Clark]

oh bingham only lists the suggested stacks for their 68" T/D longbows.

This is where the #7 rule comes into play for LIMB length.  

Their suggested stack for say a #35 68" longbow should increase to #42 for 66", #49 for 64", etc. (considering that a 17" riser is used for all)

If using a 15" riser then their stack for a 68" bow will become the same stack for a 66" bow, because the limbs are remaining the same length.

This is just what they told me, take it for what it's worth.  

If you disagree call them, don't take it out on me.

[M P Clark]

When you talk to Bingham, their 68" bow actually measure just over 67", so they round up to the next full inch by the way.  Anyways here are some pics.

 

 

 

 

 

[M P Clark]

Dang It, try this

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[cunruhshoot]

Thanks so much for all the good insight! I am getting ready for take-down bow number 2.