A pair of test bows

[kennym]

I've wondered about this for a long time, what difference is there in flat grain core vs edge grain ???

So I built two bows, 3 lams each all from same board of hard maple. All sawed and ground at same time to get all thicknesses same, or close as possible.

One edge(close as I could get from same board)  and one flat grain.

Riser is walnut, cut from same piece , end to end.

Used Bearpaw black glass .040 x 1.5, cut one for first bow ,then second and repeated to get as close as possible on stiffness...

Built on my forward handle form to get the most reflex possible.

Will get some pics up after while. I've weighed them and shot thru the chrony. Need to weigh the arrow to see gpp.

Any guesses to weight and performance? 

[Roy from Pa]

Edge grain won out by 4 pounds?

[Buemaker]

Not much difference is my guess.

[Longcruise]

Winner not more than 2# up.  Draw weight too close to call it the diff in the lams.

[Mad Max]

Edge grain won out by 4 pounds?

2 pounds

[Crooked Stic]

Well the edge grain prolly faster. Might not see it with the eyeball tho.

[Roy from Pa]

I guess ole Kenny will draw the winner in a week:)

[OldRawhide42]

Almost the same weight but edge grain a little faster.

[kennym]

Couple pics, gotta weigh the arrow . It’s a gt blem 500 with 200 up front, think about 500 grains

 

[kennym]

Excuse the mess , got myself into building a coffee table …

[kennym]

Any further guesses? 

[kennym]

Ok some stats

Put shooter machine on bench to draw for weight, these are average of three pulls at 28”

Flat - 42.24
Edge-42.28

Speeds averaged

Flat - 174
Edge-174

The only difference I found was laying on bench unstrung, the flat grain lost 1/4” of reflex compared to the edge grain.

When I saw that I figured it would be less weight and slower . Still don’t get that but that is the stats .

Satisfied my curiosity !

Now to finish them up and maybe hunt with one next fall…

[Roy from Pa]

Cool.

[Crooked Stic]

Looks like you got some draw left in those limbs.

[kennym]

Quite a bit left, that is 28" on a 60" bow.  I should do a DFC on it while I have the machine clamped on bench.

[Jeff Freeman]

Ok some stats

Put shooter machine on bench to draw for weight, these are average of three pulls at 28”

Flat - 42.24
Edge-42.28

Speeds averaged

Flat - 174
Edge-174

The only difference I found was laying on bench unstrung, the flat grain lost 1/4” of reflex compared to the edge grain.

When I saw that I figured it would be less weight and slower . Still don’t get that but that is the stats .

Satisfied my curiosity !

Now to finish them up and maybe hunt with one next fall…

Cool test Kenny. Nice draw weight too. JF

[kennym]

Thanks Jeff, I've wondered how much difference it would make for quite awhile. Now I know...

[simk]

Thanks Kenny for posting.

In fact I'm not surprised.

Did you do the same test with different kinds of woods also - maybe heavier hardwoods vs lighter and softer woods - and found significant differences? I often thought about what differences the type of midlam could make and thought that the only thing that matters is more or less mass - mechanical properties do not really matter?

cheers

[B-JS]

Thanks for Testing.
Matches my expectations.
The stuff between the Glass does not really Matter.
If it's extremely heavy or light... It may slightly slower or faster, but If it's Bamboo, Maple, Ash or whatever is just about personal preferences.

[Buemaker]

Cool, thank you.