Osage Sapling Sapwood - tillering check.

[mwosborn]

Just wondering if anyone would give suggestions on tillering out this osage mostly sapwood bow.  It was cut last April - about a 3" diameter sapling.  Split and clamped to a caul for a couple of months to keep from warping badly.  Then has been drying in the shop since then.  63" tip to tip.  1-1/4" wide to midlimb then tapers to 1/2".  Back of the bow is just under the bark.  Most of the heartwood has been removed to this point although some does remain.  The larvae had eaten some holes/trails in the sapwood - these were filled with titebond 3 and sawdust.  Bow was then backed with rawhide.

Currently I am out to 23" and it is pulling just over 50#.  I am wanting to get to 27" or 28" and 48-50#.  The upper limb is on the right.  The arrow pass is centered on the tree.  The original unbraced profile showed just a bit of relfex.  Starting to show a bit of set - more on the upper limb.

At 63" do you think I need to get the fades and handle bending some to get to 28"?

Thanks,

Mitch

[burchett.donald]

  Just my 2 cents, if you know where your arrow pass is put the hook/rope where your nock point will be...This will change things some...It couldn't hurt to get those fades moving a bit more...Making the handle bend would be some insurance.
                                                                                                                    Don

[bradsmith2010]

if the bow is showing set,, then listen,, it may not be long enough for your 27 or 28 inch draw,, especially since it is all sap wood,,
I would even the tiller and leave it there,, and use another piece of wood for a longer draw,,

[cdpbrewer]

Donald's on the right trail, but, since you've got it to 20" I'd shoot it a bit to determine where the best nocking point is and where the center of your hand's pressure is on the bow's grip.  Use those points on your tillering tree- with a fulcrum where your center of hand pressure is.   The pulley rope should come straight down as you draw the bow on the tree and the limbs shouldn't rock on the fulcurm as the limbs return to their braced postion.   Looking in a mirror helps some folks but it just confusing me. 

Since the limbs are constant width to the midpoints,  the tiller should ideally be more ellipitcal than circular.   i.e. more bending from mid-limb out.  Judging by the set in the unbraced photo (assumming the limbs were straight...),  it looks like they are stressed enough there already so I'd gingerly thin the fades and maybe the handle to get a longer draw length.    Based on the set, I suspect it'll be a slow shooter if you can get it to the draw length you want.    Given the short length, the set, the grub holes, and sap wood, I have doubts you'll get the 27"- 28" draw lenght. 

Please post on how the grub hole filling holds up.   Titebond creeps when stressed....

c.d.

[Jim Davis]

right limb is bending more at the fade and less in the outer third. So, after getting right outer third bending a little more, the whole left limb will need some scraping to keep them even.

The above will  get you another inch or two of draw. If  things look good then, you could scrape both limbs evenly to gain some more draw length. Be very careful about scraping near the fades and on the handle. A little reduction there will make a big difference and could lead to a hinge at the fades.

I think you ought to be willing to consider calling it finished if you get to 26". But, with the right thickness (or thinness) shorter full draw bows have been made. Making any bow is a risky endeavor.  Making a short full-draw Osage bow with sapwood in the mix just makes it  more interesting!

Jim Davis

[mwosborn]

Thanks for the help guys - will work on it some more this afternoon hopefully.

[Sidewinder]

Mitch I'm glad you posted this mostly sapwood bow. There was some discussion earlier on another thread about using osage sapwood that wasn't directly related to this bow but it is interesting that your making one mostly sapwood. Are you going to heat treat it? I will be interested in hearing how it performs. I think the tiller advise given does'nt need any more elaboration so I'll watch and see how your finished product satisfies you. Hope it turns out good.   Danny

[mwosborn]

Worked on it a bit.  The first pic here is the same one in the original post except with an oval added.  The second pic is after a little bit of scraping.  I pulled to 24" now and it is currently at 50#.  I think I will slowly reduce some weight and see if I can get it out to 27" without going BANG!

Danny - I think I may heat treat it just to see.  I think it is going to be sluggish so I might as well try.  I have had good luck heating ash and hackberry, but have never worked with hedge sapwood before (and only a few heartwoods).  I cut this sapling because it was so darn straight and I thought it would dry relatively fast.  I cut some nice staves from a fairly straight section of a 10" trunk at the same time - will be working on one of those shortly!

[mwosborn]

Think a few scrape on the outer third of right limb yet?

[Pat B]

Have you tried Eric's Tillering Gizmo? He has a "How To" in the "How To" section.

[mwosborn]

Yes I have Pat - thanks.  The gizmo is showing the limbs to be bending pretty close to the same now.  I am still trying to develop a "tillering eye" so can always use some help from those that have developed one.   

[Joec123able]

Looks pretty dang good

[Jim Davis]

Think a few scrape on the outer third of right limb yet?

Yes, I said that before you drew the elipse (not oval,  btw).

[mwosborn]

Will do Jim - thanks.  I did take several scrapes off that section already - will do a few more.  You are correct an "elipse" is the correct term. 

Thanks Joe.

[mwosborn]

I got it out to 27" without breaking it (right at 50#) - however it did take quite a bit of set - 1-1/2 to 2".  Especially in the outer 1/3 of each limb.  Shot it a few times in the garage at 7 yards (it is below 0 here today) and it draws nice and doesn't have much hand shock.  However, the set was bothering me so I decided to clamp it down flat on the bench and toast the belly.  I will let it set a couple of days and revisit the tiller.

In hind site I might have been asking too much of this piece of wood given my level of skill!  Stiff handle design with the wormy sapwood and 63" total length pulling 50# at 27" resulted in lots of set.      I post some pics when I get back to it.