Vine Maple - Compression versus Tension examples - Example #2!!!

[330bull]

Hi Folks,

I know that VM has been a hot topic lately, especially since I have been pimping it pretty hard (see trading post).  Oh yeah...and Gordon has been cranking out some killer VM bows!!!

Here are some pictures of a stave that I cut and roughed out for Chris in Texas.  The bottom half is the compressing side, while the upper half is the tension side.  In an ideal VM stave, the tension side automatically has reflex built into it.  And as you can see by the pictures, the tips already have 2-3" of reflex right out of the bandsaw.  This provides a lot of "pop" in a VM bow.

Enjoy!

Joe

Folks:  Scroll on down to my 3rd wave of pictures, I think I show how much more energy is stored in the tension stave!

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[Pat B]

Cool VM stave.  I have never worked VM but have heard that only one side is worth making a bow out of. I imagine it is the tension side. I'd bet the compression side would deflex a bit after splitting.   Pat

[Justin Snyder]

That is a pretty cool demonstration. Looks like a left handed bow to me.  Justin

[duffontap]

Nice character stave. 

      J. D. Duff

[DanaM]

Joe, I haven't had time to do anything with the staves ya sent me. busy, busy, busy
Nice demo

DanaM

[330bull]

Oops I forgot the full length stave picture.  You can still make a bow from the compression wood, but you'll need way more limb mass for the same poundage, which will result in less speed overall.

This bow should be able to be RH or LH pretty easily.  Yeah this was a character bow but I guarantee it will sling some arrows.  The more I work with VM, the more I am determined that Tension sides are the ONLY side to work with.  It's just so much more efficient.

Joe

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[330bull]

Here's example #2.  I have no idea what's motivating me to do this; I guess I'm pretty excited to show everyone the "magic" of Vine Maple.

The first three pictures show another stave I cut in half yesterday.  The lower stave facing "back down" is the compression side.  The upper stave facing "back up" is the tension side.  Notice how much more reflex is in the Tension stave?...Nuts!

The 4th picture is actually 2 pics spliced together.  I show how straight the compression stave is when stood up against a post.  Then I pull the stave from the center towards me.  This force is the same force applied as if being pulled back like an actual bow.  Notice how much the compression stave bends?

The 5th picture is actually 4 pics spliced together.  From left to right, the stave is placed against a post with no force.  Notice the natural reflex?  The second frame shows me applying the same force as if being pulled back like a bow.  I could BARELY budge the stave.  The third frame is a 2nd attempt to budge the stave, no dice.  The 4th frame is a non cropped pic of me from the 3rd frame.  I attempted to show that I am not a small dude; I can apply a decent amount lot of force.  However, the tension side has SO MUCH energy that I can barely budge it.  This  stave will make a smoking hot bow.  The beauty of VM is that it is EVERYWHERE in Oregon.  I love it!

As a last note, the piece I used was cut directly in half.  Both the compression stave and tension staves were the exact same thickness.

I hope you enjoyed the show and learned something from it.

Joe

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[Gordon]

You call that tension wood? Now this is tension wood...

Harvested in December and was straight when cut.

[330bull]

Nice!  I'll bet that this stave will do the same with no bark after a few months!

[white wood]

question for you Joe. when you bandsaw the staves in half, how do you know which is the center for tension/compression. for example, how do you cut them in half not knowing which side is compresion/tension? can you tell by "reading" the stave which side is which? are there any tell tale signs like limbs on one side but not the other or are you just taking the chance when you cut them in half? just wondering how you tell which side is which before you cut them, thanks -jesse

[Gordon]

I don't know how Joe does it, but I mark the tension side before I cut the tree down.

[Gordon]

I'll bet that this stave will do the same with no bark after a few months!

Yep.

[white wood]

gordon, how do you tell which side is the tension side? are there any signs on the bark that let you know? -jesse

[330bull]

I just "scuff" the tension side with my saw blade.  It's that easy.

I made a simple picture that helps describe how to identify tension versus compression.  Essentially the perfect piece is one that starts almost horizontal and then curves UP, not DOWN.

Enjoy!



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[duffontap]

Good examples Gordon and 330.  Keep up the advertising.  There is no shortage of this super-strong stuff. 

        J. D. Duff