Ozbow

Hello All,
First post, i have been hanging around and reading the forums for awhile.
This is a bow i started a few years ago but was frustrated with the sinew lifting from the sides of the bow, a few weeks ago i decided to peel the sinew off, soak and re apply the it, which turned out great. it is kangaroo leg sinew backed spotted gum, it started out as a pyramid design but kinda ended up as a lever bow, the outer 1/3 of the limbs do not bend, drawing 50#@28 its taken less then 1/2 in string follow so far, at the moment i am using nylon para cord as the tillering/bracing string while the b50 i ordered from ebay gets here.
I have noticed a bit of hand shock, more then i would like, I'm thinking its a combination of the stretchy nylon string and tips that need a bit more reducing in mass (the tips are still in pyramid profile, didn't want to reduce the width until i knew the final weight)
Its far from finished, still need to finish off the handle section to make it fit my hand nicely and reduce the tips as mentioned earlier, the knocks at the moment are sinew wrapped at 45 degree angle, they need to be filed in and wrapped again but its shooting fast.
Felt like sharing, can anyone see anything in the tiller that's not right? Keeping in mind its a lever bow not a long bow.

Thanks Guys.
Harry

Hi Harry, the bow looks good. The Lever bows require a fair bit of mass reduction to minimise the shock. A fast flight string will assist with the shock too.
What glue did you use for the sinew backing? Thanks Steve

Hey ya Steve,
Hide glue was used for the sinew backing.
Have Learned a lot about sinew backing with this project, the first attempt i tried to use minimal glue as advised and when i went to wrap the bow with ace bandage i was very careful with the wet sinew, this time i used plenty of glue and wrapped it as tight as i could get it, so tight the excess glue was seeping through the bandage, seems to be working out great

Hey static, lovely lookin bow mate where did you source your sinew? And was the bow from a board or a stave? Where abouts you from?

Well done mate. Was the hide glue like the stuff from art stores for sizing canvas'? Cheers Steve

Hey ya.
The sinew is kangaroo tendon dog chews the Spotted gum is from a board, flat milled surface with growth rings cut through was used as the gluing surface for the sinew.
The hide glue is the granulated stuff, was advertised on ebay as musical instrument glue.
Im from Melbourne, should probably put that on my account info.

Thanks for all of the complements on the bow guys.
Harry

Ha no kidding! I was lookin at them roo tendons at my local pet stock up the road in carrum a few weeks ago....wasn't to keen on getting them though as the only size available was a 4kg bag and they wanted $60 for it!, how long you been makin bows for harry?

Cameron

Hi Harry, welcome to Ozbow.

Your bow looks as though it was styled after a Danish flat bow sometimes referred to as a Holmegaard / Möllegabet / Ringkloster or Vedbaek bow.

If you are going to reduce the mass of the levers as suggested by Steve it may pay to take some off the sides if possible and a little less off the belly.

I agree with Steve that a fast flight string will assist in reducing the hand shock.

Limb timing may be a problem, also have you tried different hand placements, up or down to change the pivot point?

Daryl.

Hey ya,
$60 for 4 kg is good Cameron, they want $50 for a kg here, some pet shops sell them in 200g bags.
Have been making bows unsuccessfuly for a couple of years, mainly kids bows and bows for me that turn out at a low poundage, this is the first one I am really proud of, been shooting for 20 years
As I said in the first post it was designed as a pyramid profile but ended up as a lever bow or holmigaard, tried to avoid using the "holmigaard" title as its all the rage right now and I'm not one for being part of the "in croud"
Have not tried moving my bow hand around yet, but I will before I start on the finishing touches on the handle

Harry

Morning Harry.

StaticRecurve wrote:... ...I'm not one for being part of the "in croud"

You could change. http://www.youtube.com/watch?v=OOWO--z1S8A

People get a tad hung over names. Enjoy the Music.

Morning Grahame
Lovin it

GrahameA wrote: You could change. http://www.youtube.com/watch?v=OOWO--z1S8A [/i]

I'm glad someone got the joke.

Harry

Good work Harry, you bought back some memories for me. In 1995 under permits I shot 7 Grey Kangaroo's. It took me 8 hours from memory to cut the Sinew from the Legs, Tails and Backs of the Roo's. After 5 or 6 Hours in the October morning Sun the Pile of Roo's was starting to Stink some I tell you. I used the Waste Product and Rabbit Skin Sizing from an Art Supply Store to Boil up the Glue.

I found the Sinew from those 7 Roo's was not quite enough for my Bow, how many Leg Sinews did you use ? I reckon get yourself a Kangaroo Rawhide and Twist yourself up a Rawhide String, they shot well

regards Jacko

Hello Perry,
Its hard to say how much sinew went into the bow, it was started a few years ago, at a guess i would say 15-20 leg tendons went into it but i cant be sure as they went on in stages.
the first layer was the entire back of the bow, left it dry for 3 ish weeks and took the ace bandages off, and left it for another week, when i went to work on it the sinew was lifting from the sides, got frustrated and put it on a shelf for a later point.
2 years later or a few weeks ago i took it off the shelf took a butter knife pried the sinew all the way off, it was still attached at the tips and i was surprised at the amount of elasticity the sinew had when i bounced the weight of the bow on the sinew with them separated.
I then soaked the entire layer of sinew in a bucket of warm water for 5 hours and started pulling the sinew backing apart section by section, when i had it all bundled up again I started re applying it in the same manner as before, 1 layer over the entire back, but this time i used lots of glue and lots of pressure with the bandage, after that layer was dry it turned out to be a lot thinner than i had imagined it would be so i processed 5 more tendons and applied it straight up the center of the bow (tip to tip) to raise the sinew into a rounded back to get the sinew to do more work.
When the second layer was dry i started tillering, i ended up over tillering the inner limbs, and was very angry with myself for a few days..... then it hit me, i can just add another layer of sinew to the inner section of the working limbs, so that's what i did, another 5 tendons.
when i strung it for the first time after the 3rd layer was dry it's tiller was perfect so I took it to my bathroom scale and weighed the draw weight then took the picture at full draw, it has now changed tiller a bit and needs a small amount of work on the outer limbs before it is finished.
Have lightened the tips, now for proper string knocks, finishing off the handle and final sanding.
Just wanted to say again how much i appreciate all of the comments, thanks guys.

Harry

Hi harry, thanks for shareing your experience. Do you know about sizing the back off the bow with glue before laying down the sinew? Probably why the sinew started lifting. By the second attempt it was probably suitably sized with glue. Plenty of build alongs on primitive archer. Cheers steve.

haha.. my last post was from an old account, don't even use the email anymore, had the credentials saved in the login window haha.

The bow was sized and roughed up.... maybe not sized enough?
Thanks.

Harry