Maple backed black cherry bow - a question

[Tuomo]

Let's have a little guessing - what is (was...) maximum draw length for this bow? I know the answer but what you would say?

Sugar maple back, black cherry belly. Length 73,6 inch, max width (handle) 1,12 inch, tips 0,4 inch. Pretillered before gluing, tapered but not really tillered. Backing strip is cut straight from a big plank, good grain but not near perfect.

So, what was the maximum draw length and draw weight before exploding?

[Yooper Bowyer]

Really depends on the quality of the back and the thickness of the limbs.  where you trying to break it?  I would guess somewhere over 30-35"

[Tuomo]

I made a mistake with this bow, so the only option was to test, how strong it really was. I was surprised.

It was about 47#@28" – but the final draw weight and length were much more.

Result after maximum draw length:

[Yooper Bowyer]

I made a mistake with this bow, so the only option was to test, how strong it really was.

That must have been a really bad issue, most mistakes are salvageable.  It looks like there weren't any serious weak spots, it seems to have broken everywhere simultaneously.  It would take a lot to give cherry the kind of set that one piece has.  There was a guy here not long ago that blew an oak bow at 40 some inches

[RyanY]

First picture looked good. Not sure I could make a great guess but it looks like you answered your question. Was it taking set before the break?

[Tuomo]

I would guess somewhere over 30-35"

More...

[bownarra]

Dunno
I did a similar thing with an elb that wasn't doing what it was meant to...it went to 40" and still didn't blow, my tillering set-up was maxed out haha I still have it somewhere, that was a hickory/ipe bow.

[Tuomo]

it went to 40"

More...

[Deerhunter21]

it went to 45"

[HH~]

If it went to 40" I dont think there was much wrong with it lets see 47@28" 50@30, 70@40" or near abouts. Hope you had your skid lid on when that Sucka went Bang!

Hedge~

[Tuomo]

it went to 45"

More...!

It measured 83#@43" – and it had still a lot of more life remaining.

Here is 45" draw.

[Hamish]

Lol!

Looks like maple and cherry is a good combo.

[BowEd]

Interesting experiment.Those are every day Howard Hill poundage shooting draw weights.
Your bow looks afterwards like a sinewed D/R  to 6.5" red cedar from a stave I did years ago.When they go they go off with a big bang.
The hidden culprit that can infiltrate a black cherry many times with time surviving when being over stressed is that it'll chyrsall or fret on the belly.
I have an awful pretty 64" sinewed on only the working limbs black cherry holmgaard that chrysalled just a little after a couple thousand shots through it.Still shooting it though and it still looks healthy holding 4" of reflex at rest.
If a person is paying attention to the draw weight as you pull farther and farther on the tillering tree and the draw weight starts decreasing that's the sign it's degrading and getting ready to blow.
That sure is a heck of a long draw though.

[Tuomo]

The hidden culprit that can infiltrate a black cherry many times with time surviving when being over stressed is that it'll chyrsall or fret on the belly.

The interesting thing was that there were zero, not a single fret or chrysals, nothing. It just took set, about 4–5".

But, we are now at 45" draw and it is still going strong! But how far?

[BowEd]

You shoot em long enough that way over stressed and it'll happen even though it does'nt show immediately.