holmegaard challenge--all bows finished...pics galore

[radius]

Yeah, i dunno PK...the ones i'm making are essentially going to follow what Dennis LaVarenne has to say, namely:

the HOLMEGAARD bow has 5 sections:

1.  handle section which doesn't bend
2. two bending limbs
3.  two non-bending lever tips

I think i might follow Robert's advice.  Make the longest levered bow first, and then narrow the limbs of the other two accordingly.

[Parnell]

Howdy,
Wow Robert, that is some clear thinking.  I brought my oak indoors for a few days to get it out of the humidity, down here.  I've got the 66 and 55" boards cut.  2" wide.  I was reading TBB3 last night, my wife picked it up for me a few weeks ago for my b-day along with an antique draw knife and antique pipe.   No wonder she's still on my good side.  But, I digress.
I was reading the bows of the world section discussing Holmies.  They list dimensions for a 52 inch design tillered to 25".  I read past into the Meare Heath section and it discussed bowyer height and bow length.  Average height was shorter in the past.  Myself, I'm 5'10" and draw 27".  Average height thousands of years ago for Caucasian folks was what 5'6" or so?  I'm thinking the 25" draw @ 52" length for a 5'6" man about corresponds with my 27" draw at 55" got me thinking of following this experimental design, 3 bows same length 55 inches and lever lengths as the independent variable.  Let me know your thoughts as I haven't cut anything yet (letting wood de-humidify). 
And Radius, the tiller tree is low but it's a good space saver.  I use a folding portable campers seat that I set up when tillering there.  It does the job!  

[AKAPK]

 

[radius]

some progress...i have the longest-levered stave ready to tiller.












Robert was right, i think, whoever he is...this one has 2" wide limbs...the next two i will make progressively narrower....

[radius]

This one is now drawing 40# at 17" with a 1" brace.  The bending limb is 1/2" thick all over.

 Today was quite a day on the gauntlet.

PROGRESS

I noticed that no matter how much i scraped the limbs thinner today, the draw weight didn't change.  What changed--and this was very interesting--was the area of the bow where i could feel the spring energy.  At first i could feel it uncomfortably too much in the handle.  I thought the thing would break.  So i scraped the inner limbs.  Scale, tree, vise, scale, tree, vise.  The draw weight at a given length changed very slowly, but gradually the bending-force moved away from being centralized in the handle and now it is spread throughout the inner limb. 

So far the thing shows no real set.  I have drawn it to 40# probably 1000 times already.  Well, maybe 800.  Oh my back.

[radius]

TIP MASS

The tips are actually pretty light.  They are 5/8 wide or so, almost an inch thick, but solid white oak and really strong.  Once the limbs are tillered out, i plan to carve the tips, leaving plenty of strength but adding character and losing more mass.

[sailordad]

so far so good
but the left limb looks stiffer

[TBod]

If you make the limbs narrower on the other bows it's gonna be harder to compare them..

You will be changing to many parametres.

Wasn't the objective to find the ideal length of the lever?

[radius]

not length of lever by itself, but the ratio of bending limb to non-bending limb. 

I think Robert has a point.  The thinner the limb, the wider it has to be to store the same energy without taking too much set. 

One thing my objective is NOT:  and that is to ruin two staves while making the 3rd one great. 

I'm not using the scientific method here.  I don't have a pre-formed hypothesis of what the results will be (eg, the short-limbed bow will break, or anything like that).  Instead i am just experimenting with the design.  I took Robert's advice in 2 respects.  One, I lowered the target draw weight to 40#.  That's still legal hunting weight here.  Two, i will probably make the longer limbs progressively narrower, or else they will end up being 1/8" thick!

It's possible that any of the three ratios/designs will work, provided the limbs are crafted accordingly.  That's fine, too.

[radius]

HEAT TREAT....what's the consensus on heat-treating white oak?   

Marc St. Louis reports that it rates as 'EXCELLENT' in terms of reponding to heat treatment...i guess this means it increases cast and doesn't break.  I think i'll give it a go...i need a day off tillering, for the sake of my poor back.

[Parnell]

I'm looking to do some wood removal tonight.  I haven't used white oak, yet, with heat treatment.  Is there some sort of a list of woods that respond well with heat treatment and others that don't?  Just curious.

That bow is comiing along nicely, makes me want to start to jump on mine.

[radius]

i really like the shape!  These bows are damn cool.  My roomie came in and said, "Wow, that thing looks fierce!"  Being such a hard wood as oak, this weapon definitely doubles as a bludgeon, once the arrows run out...

[Josh]

TBB 4 has a section on heat treating wood by Marc St Lois. There is a list there. 

[radius]

thanks yeah, i just read it...he says he hasn't actually worked this way with white oak, but that from what others tell him it rates as excellent.  I am going to do it.

[Parnell]

Well, I've made some progress.  These are 55" long, 4" handle, all fades are 1" and as of now 2" wide for bending limb.  The top two are identical; 12" levers: 12" limbs, then 10":14", and 8":16".  Top two are same, I may make one lower poundage later for my nephew as a kids bow. 

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