Tiller plus questions walnut sapwood

[stuckinthemud]

This was a gift lath from Del, it is walnut sapwood cut on the quarter, but I am not the master he is, I got the limb centres working too hard too soon and ended up with an inch of set. There is one knot I am a little nervous about, it is only on the belly and cuts through half the thickness of the limb. The unstrung photo is about 5 minutes after being unstrung. The drawn photo is to 10 inches. Currently I am undecided whether to pike it and fix draw lenth to 9 inches, or try to get it out to 12.  I think the tips need to move more, they are an inch wide at the moment, so plenty of scope to narrow them rather than thin them. What do you all think? Please be honest

[Del the cat]

I was surprised how well the bow I made from that same walnut turned out... but of course it was a lot longer and only 40#
Shame about the knot.
I'd strap it down flat heat treat the belly, get some thin superglue or epoxy (warmed with a hot air gun) into that knot/crack. The nhave another go trying to get the tiller as good as possible.
Del
Here's the whole playlist for the walnut bow (skip the 1st one  )
https://www.youtube.com/watch?v=3qqUKCNhT5w&list=PLBz2tD9476KRuVA_Fkpzav-457zLavBU5

[stuckinthemud]

Cheers Del, will give it a go, the bow is only showing a half inch of set in each limb this morning.  I must have measured the set before the bow had finished de-stressing . Any thoughts on heating in some hooks?

[Del the cat]

... Any thoughts on heating in some hooks?

Yes... Don't!
A crossbow prod is short enough already without adding extra stress/reducing draw.
I actually favour a bit of deflex in a crossbow prod. Because the power stroke is so short, I figure I'd rather have an inch of deflex and an extra inch of power stroke rather than an inch of reflex and an inch less power stroke!
Del

[stuckinthemud]

Ok, will give it a good heat-treat and focus on getting the tips to come round more. Draw weight will end up somewhere around 30# but a long power stroke will make the most of it.  The alternative is to cut 4 to 6 inches off and go with a 9 inch draw length

[stuckinthemud]

Gave it a heat treatment and got everything really straight but it wasn't really a thorough going over, the straightening would almost certainly pull straight out , so after a few hours I gave it a thorough heat soak, carefully heating the belly until the back started to feel warm. Not much of a colour change but the wood relaxed back into just over a half inch of set in each limb, 1 1/4 total set, but, I can live with that.  I also flooded the troublesome knot with ca as it opened a little in the heat. I glued it and swelled it shut with a little water. I'll leave it a day or three to rehydrate and have some fun building the tiller.

[bownarra]

I'd be very concerned about that little knot. My predicition is that it will fail there.
If you had to save the walnut I'd flatten the belly , lose the knot and glue on a new belly of something dense or yew.
Get the mid to outer limbs bending more.

[stuckinthemud]

The knot opened into a split under heat and, ironically, this allowed me to get really good penetration with CA thickened with wood flour I am fairly confident it will hold as it is only under compression. If it starts to fail I will pike the bow and use the off-cut as a belly patch