1" Lilac sinewed-Tiller help please

[loon]

  Awesome. Good luck.

Haha, I like string bridges. You could make really wide ones in a bit of a crescent shape to catch the string, or like mongol bows I can't find pictures of. Could make them smaller once you correct the bow and get it really straight and stable as can be..

Really wide string bridges on Mongol bow -

[DuBois]

Got her to brace with a modified version of Marcs jig (clamps and leather wrapped progressively thicker wood pieces) but I guess I need a pre stretched string or something  cause it pulled out a lot even though I had it as tight as possible before letting the clamps loose. I found myself reaching for some erasers and leather scraps and holding bridges in briefly just for a visual before it flipped on me.

Alignment stayed surprisingly good throughout tiller and I would have maybe been ok without bridges except I made the base of one siyah narrower than the other (One is wide cause it has the bows only gnarly knot at the base of the siyah). Belly s flat as a pancake. I kinda like the idea of elevating the string off the angle of the siyahs and at the same time increasing the pre draw angle of the siyahs, if that makes any sense. Probably not sayin it right 
Not sure on the weight but it was pulling around 50# to get to brace height on the tree. My pulley loop snapped off about that time so it was time to brace her up 
Never done bridges so not sure.

What next?
sinew or rawhide wraps?
wood, horn, leather, bone...

And yes Parnell, I have been thinking about horn on the belly but this seems somewhat tough enough for me already 

Urufu, do you have some other angles of those long levers?

Thanks all

[gfugal]

Looking at how far it has to bend even at brace reminds me of the bows I've worked on. They didn't turn out the most successful, but you on the other hand have more skill/experiance and the benefit of large levers. However, I am curious how far your planning on drawing it. This is going to be a highly stressful design especially if its just a wood belly. Its probably too late to slap horn on now  .

[PatM]

Lilac is about as horn-like a wood as you can find.  Get some rectangular blocks of wood and groove them roughly to fit the belly side of the siyahs  and lash them in place. Experiment with location until you find the best spot for them.

[BowEd]

Yes what Pat said.I had a whole long response typed out and the site went off on me erasing my post....lol.Lashing a notched piece of wood to the heel of the lever.Just get it to brace and see what you got.I'd use a FF string so it does'nt stretch so much too.I did'nt realize lilac was that way.

[DuBois]

Ok Pat, will do.

Dang Bman, I would have liked to read it.

[BowEd]

Well I said mainly to get it to brace and stable like said with the bridges.To see what you got.The limbs have not been pitted against each other yet to see what the tiller exactly is.The question of horn I commented on.Depending on thickness of it put on will increase the poundage a fair amount too to remember.Wood removal would be in order first to have a 50# bow.1/16" thick will increase it again a good 10 pounds.2 17" long laminations butt jointed at the handle and sinew wrapped to boot is a bit more work yet.I've never worked lilac so I did'nt know like Pat said that it is that good in compression.You may not need it.

[JNystrom]

Just btw, i have NEVER seen a compression mark in my lilac bows. Lilac is crazy elastic and strong in compression. Even though its already springy and tough, i experimented with toasting the belly and it makes the wood even better. Lilac is quite amazing stuff, i wouldn't (and others here in Finland) make bows from any other wood if i had plenty of knotless and straight lilac.
.80 sg? About.

Those string bridges are nice idea, i happened to have a similar problem as DuBois now.

[Redhand]

Man Marco you have made good process on that stave. Great job!  Can't wait to see the FD pic.

[joachimM]

That's a rather heavy draw weight to get at brace. My main concern would now be:
Did you put enough sinew to take most of the tension load at full draw? If not, and the bend radius is thus small that the stretch of the wood under the sinew exceeds 1%, the bow is still at risk of breaking.

I would also keep the mass principle in mind, with some allowances for the amount of sinew. Making a 65# backed bow with the mass of a 40# wood bow seems risky to me.

[Parnell]

The progress is real interesting.  Hope it turns out to shoot well!

[Urufu_Shinjiro]

Does that help any? Obviously with the non-horn nature of your bow the working limb will have a different profile than the kasan eye of a horn bow, but I agree with making it slightly bendy handle and doing a cork buildup handle, I think you may actually pull this off and make a really unique and cool bow. Good Luck man!

[DuBois]

Thanks Ed, gonna keep at it without horn for now and see what happens with bridges added.

JNystrom, good to hear how lilac is over there. Gives me hope for this one. I'll post pics when I get some bridges on.

Joachim, it is decrowned and was 3/8" most of the length and built up with 2.65 oz. moose sinew. This was the first time I tried weighing and separating it per limb and I think it really helped even things out. It now has a crown like it did before decrowning. I'd have to measure but sinew is easily 3/16" thick at handle so I think it will be very effective no matter which way I go with all this.
Never played with the Mass principle but I'm not going for 65#, only looking for upper 40's to low 50's

Thanks Parnell and you to Urufu. Awesome pics and bows.

[BowEd]

In hind sight DuBois a gol darn 6 or 8 inch tapered handle could have been glued down on the backside for a handle.Then sinewed over that heavily.Wrapped around the fades etc.You get the idea.Like a regular horn bow construction.If a stiff handled bow was wanted anyway,but then horn might have to be in order too then.Who knows.Oh well roll with the punches anyway.
I'd sure like to see it shot I know that.Unique piece of wood.2.65 ounces.That's a good amount on that stretch of wood.No wonder it pulled 50#'s.

[joachimM]

You surely weren't frugal on the sinew!
Getting more and more interested in how you're dealing with this bow.
I personally find the mass principle very valuable for estimating safety margins and knowing what poundage to expect from a stave.

Keep us posted!