Friday, 28 September 2012

Final Adjustments and Angst

The bow wasn't really comfortable in the hand , so i extended the grip down a bit towards the lower limb keeping a careful eye on the thickness of the limb. I couldn't narrow it down into the thin section.
it feels more comfortable now and the hand isn't pushing the arrow up above the arrow plate.
It shoots sweeter now and the finishing has dropped a pound or two so it now draws about 48# at 28" and I pulled it back to 29" where it showed 50#. (I normally test bows to 1" overdraw)
The second pic shows the nice figure on the belly of the top limb.

I was wiping on another coat of Danish Oil when I noticed a couple of tiny compression marks on the belly on the upper limb. I wasn't amused as they had just appeared out of the blue. This is what caused my angst. Should I just leave well alone or fiddle with it?
Chrysals aren't fatal, they are just ugly! I've had bows with the odd few chrysals which I've bound with thread and epoxy that are still shooting well, I have one old Hazel bow made in 1 hour with it's belly smothered in chrysals running right across that still shoots.
The chrysals basically warn that the bow is overstressed in that area, maybe drawing it to 29" was enough to cause them .
It's not an issue as they are barely visible, however, it's also not ideal and I decided the tiller was perhaps a tad too elliptical and a little judicious relieving of the inner 2/3 of each limb (especially the lower which could be seen as a whisker stiff) was in order.
Basically I ran a coarse file/scraper and sandpaper of the belly areas in question and also rasped a whisker off one edge of the lower limb where it was wider than the upper.
These precautions will take the load off the outer 1/3 of the upper limb, the down side is it sacrifices a hint of draw weight, we are just talking a pound or two here, so the bow is still over 45#.
Hard to tell if it's my imagination but I think it feels smoother now, hard to tell as I have a bit of a cold and I'm only good for 10 minute burst of work.
These things always seem to bite you on the backside at the very moment you think you've finished. I'd just posted some pics of the bow on Primitive Archer and it grieves me to confess to my little bit or re-tillering.
Still a stitch in time saves nine and other pithy old saying.

A bit about nocks:-
Here's a sketch of two nock styles and a shot of the lower nock which has less trimmed off and is rounder and more solid. Two reasons for this. a) it is likely to get rested on the ground. b) leaving a bulkier tip helps to stop the lower string loop falling off when it's being strung or stored upright.

Update:-Shot it through the chrono'
Normal shot (about 27" draw) 155fps.
Full draw using whole 28" of arrow 160fps.
Max 166fps

Final Update to this post:- I'm not happy with the chrysals so I've started roughing out the better half of the log. It still has some character, but not so severe. It's those small clusters of knots and swoops that cause the problems. You need to leave a tiny bit of extra wood around knots for security, but that can leave weak points between the knotty areas... sort of damned if you do and damned if you don't. The new stave with more gentle undulations will be easier to keep an even thickness. I'll also make the tiller a bit more circular.
Mind I won't throw out the baby with the bath water and go back to a complete arc of a circle, I may make some slightly eliptical templates. Anyhow it's work in progress.


  1. Shame about the weight loss after chrysal repair, but such is life.
    What is the arrow plate made of?
    The nocks are not what I expected, I thought they would be the side groove variety, but it makes the overall shape of the limbs nice.

  2. Never mind..I see on PA its water buffalo!

  3. If you look at the pic on the entry for 16th of August you'll see the two types of nock side by side. The slimmer style where the string loop goes down the side of the limb more requires a tip overlay on the back of the bow to avoid cutting a groove in the back and weakening the bow tip.
    I thought you wanted self nocks and thus I couldn't use an overlay and do that type.
    It just goes to show how inadequate words can be for describing curved 3 dimensional shapes!
    Tip overlays could still be done, but it would detract from the simplicity and self wood look.

  4. Hmmm, not quite sure what you mean by 'side groove'. The se nocks are actually made as a groove in the side of the bow, but once they are done the bits at the very tip of the bow at the edges are trimmed off to save weight.
    Hang on I'll do a sketch after breakfast and post it above!

  5. Its ok we are on the same page as it were.
    I was just being dense Del.
    I was recalling an old cheapy recurve I once had, same nocks as the left diagram...just not trimmed down.