Rednek Labs testing

[kennym]

Since most folks want edge grain maple for cores, I end up with lots of flat grain boards about 4” wide. So I glued a couple together and resawed lams from it. One glue line and perfect qtr sawn grain.

At testing they were lighter by 15 grains than regular edge grain(45’ grain on end of lam)

This is great!!

Then the spine test, they failed to prove out.

7/8” more flex than the plain maple.

Now I gotta make a flat grain and test it, it may beat both!! LOL
 

[mwosborn]

Kenny, how are you doing the spine test?  Just like you would an arrow?  How much does a "normal" edge grain flex using your method?  How many did you make & test?  Interesting.  Sorry for so many questions!

[kennym]

Mitch, yesterday was just clamping to a bench with 12” over the end and clamped at other end, spring clamp for weight.

This morning I got out my arrow spine tester with dial indicator so got measured in thousandths . The edge grain wins , flat grain next and vertical grain last.

Will have to cut from different boards and run again.

[kennym]

Edge grain being grain at about 45’ angle across end

[Forwardhandle]

From one RN to another RN are you saying if I slice these riser lams from the top down thats the strongest in your test ?

[Shredd]

  Good to see some tech stuff on here for a change...  I am a visual person...  I don't quite get everything that you are saying...  Could you possibly post some simple sketches of exactly what you are doing and grain alignments???  I thought edge grain is when the lam is laying flat and the grain is vertical...

   Thanks...

[kennym]

There are so many variations of grain orientation, it's hard to call each one. For the test  I called the 2 lammed together vertical(like vertical boo) , and the one like your pic edge grain , the flat grain was horizontal grain I guess.

So far the one like your pic (cut from either flat edge) has been the winner.

I thought a tech post might stir things up a bit!

[BMorv]

I was confused too, but Kenny's last post clarified it for me.  I thought edge grain was quarter sawn or vertical, but it looks like Kenny is saying his edge grain is at 45 degree angle, which is what I thought rift sawn was. 

So Kenny, I would like to hear your opinion.  When would you use flat grain as opposed to edge grain? 

[Forwardhandle]

I have read the the flat sawn lams are supposed to be more latterly stable/strong , I milled a bunch of hickory that way last year made one bow out of it seemed fine, it's nice your doing some hands on testing , rather then hear say !

[kennym]

You can get very little vertical (qtr sawn) from a 1" board, and 1"is what everyone seems to want to saw lumber into.  Actually from a 2" board it would be a small percentage.

So I think folks call anything not flat grain , edge grain.

So far it seems that the grain angled across the end of board is winning, I figured the vertical (qtr sawn) would kick its butt.

I have to cut some more boards to get a better picture of it, but on the first go flat was better than the glued up vertical grain.

Riddle me that!

[Robertfishes]

Actionwood used to be made from hard maple and lots of Bowyers thought it was a pretty good lamination.  Maybe slice it into 3/16" pieces then glue it back together..pretty sure it will be a little stiffer with the extra glue joints. That is a lot of extra work and glue..but I think some guys might like to use the old school action wood?? I started building bows in 2009, so I never used the maple action wood.

[kennym]

Hey Robert , actually a few bow swaps back I made some walnut/maple awood with tapers, putting the maple to bow center and the lighter walnut to the tips.  I don't think I ran that one thru a chrony but I remember it being pretty quick.  It might be kind of cost prohibitive tho.

Did make an interesting limb edge...

[bamboo]

i think if you played with that some there would be gains kenny--say inboard limb heavier and stiffer--and outboard limb something light--say osage inboard/red elm outboard ?
--more gain probably with wider recurve limbs
--gotta really want it!!alot of work!!

[mwosborn]

Interesting results Kenny, thanks.

[kennym]

I wrote the lam weights in grains  and deflection with  .25lb weight  down but it is still at the shop .....

[Holm-Made]

I wonder what a foam core would “spine”?

[Holm-Made]

I’m also wondering what would spine higher......a  single .100 lam or (3) .033 lams epoxied together. 

[BMorv]

My guess would be the (3) lams would spine higher because of the shear forces on the glue surfaces...but it would be nice to have an experiment confirm my guess.

[kennym]

I'm not sure on the foam, but I think 3 lammed up would spine higher, but the added weight of the glue line might make it a draw on performance.