Pin knots, limb edge

[SportHunter]

Hello Bench,

I'm looking for recommendations on this Hackberry bow and since I searched and couldn't find the answer I thought a new topic would be good reference material for the next guys running into this.

I have three pin knots riding the edge; the limbs are from 1 7/8" to 2" wide now. Two exit out the side of the limb and one out the back. I have backed the bow with rawhide and am getting ready to start really tillering but I wanted to explore all options before going forward. Thanks for your help!

Option #1, don't worry about it since its backed.

#2: Proceed with current layout but leaving it thicker near the pin knots, like islands of extra material which should increase the strength of these sections.

#3: Cut/file them out and use a side scalloped profile in this section like some Indian style bows. If scalloped most likely remove the knots leaving only good wood through the valleys of the scallops. I imagine you could go either way with this since the outer part would be under less stress.

#4: Thin the bow profile on the offending side to eliminate two of the pin knots or all three if the top one isn't too deep into the Eiffel tower section. The bow is plenty thick right now with only a few inches of movement in the tips so far.

#5: Trap the limbs to the belly. The belly has been tempered which should have increased the strength of the belly wood. Normally trapping to the back is recommended but in this case with the toasted belly trapping to the belly may be acceptable to eliminate the offending pin knots.

Two knots are 1/8 to 3/16" in on the belly and the other is 1/4".

I drew theoretical islands of material to leave if using option #2
     

Knot nearest the handle
     

Middle Knot
     

Upper Knot
     

[SportHunter]

Bow Profile

 


 

Upper limb close up
 

[mjwhitby]

I've never used hackberry but I have built an Osage that was riddled with knots coming from every direction .  It had multiple pin knot running out the side like yours. I followed the grain which ran straight through some of them , basically cutting them in half. I proceeded with tillering almost like they weren't there. I just let the bending do the talking. I've been shooting it almost every day for months now with no problems in any way.  I would say as long as you pay attention to the grain and the way it's bending you should be ok. Just my ameture 2 cents.
 

[John Scifres]

I'd get rid of them.

[PEARL DRUMS]

Id forget about them and continue. Of course Im not afraid to break a bow and start another before the dust settles.

[SportHunter]

I've made the decision to alter the layout to a more traditional flatbow with longer tapers after a section of 12" parallel length limbs. I will thin the bow limbs just enough to get rid of two pin knots in the parralell section and the longer taper section should eliminate the third group of pin knots. Planning on wrapping it up this week. Will update with results good or bad.

[Sam Harper]

You could smear a little epoxy over them with your finger.  I've fixed a few bows that way that were lifting splinters on the sides.

[SportHunter]

New profile after modifying the layout to a more traditional flatbow.

I removed all three knots. Good thing too, the top knot it had about a 1/8" hole when I was cutting it out, the side ones weren't too bad but it felt good to remove them since they were soo near the side.

 

 

 

 

One side has more reflex.
 

Now on to final tillering. Thanks for the help guys. Hopefully its smooth sailing from here.