Cable back vine maple

[fiddler49]

Here's an example of cable and bridge backing using a heavy nylon cord. I first make two separate loops, double them and loop around limbs with a ring hitch. Then thread back and forth
7 strands of cord between the two loops and tension up each strand pulling nice and tight. Then place two wood bridges under cable. Now I spiral wrap the cable to the handle,
then take about 30 feet of cord and run half hitches all the way from one end to the other. I gained about 9 pounds of draw. The bridges add a lot of tension instead of twisting the cables like Dick Baugh used in his PrimitiveWays article and makes it a bit easier. The bow is a vine maple stave I have shot it quite a bit. 63" ntn, bend in handle, 42 lbs @28 before the cable. About 51 lbs @28 now. I draw to 31.5" I'll shoot it tomorrow at the range and see if it made much difference  in arrow speed. I'll try to post the pics now? cheers fiddler49





























I got out to the range and shot a bunch with the cable back bow. It's shooting faster with the heavier draw weight!!! Here's a full draw pic.

[alwayslookin]

That's a serious weight increase.

[paco664]

That is just freaking cool! !

[Willibow]

Very cool Fiddler!  Thanks for sharing!  a 25% weight increase is nothing to scoff at 

[Blaflair2]

The bow u said was 42@28, so now is it 51@28 or 51@31.5? The longer draw my account for the weight

[bowmo]

Very cool! Looks awesome at full draw....a beautiful arc with a little Brooklyn Bridge on it! Adjustable weight on a primitive bow is def cool. I have a Penobscot that has 48 pound main bow and can go up to 68 pounds with the back bow.

[nakedfeet]

Looks like the bridges have created stiff spots, though. Could you do this without the string bridges, or lower ones?

[Dakota Kid]

I may give that a whirl next time I over-tiller. I think I may opt for antler instead of wood for the bridges. I should be able to make them much thinner. I think the thickness may be to blame in the creation of stiff spots. Would there be any advantage to adding another set of bridges?

[PEARL DRUMS]

Those bridges aren't causing the flat spots or hinges. I say that only because you can see them at brace all the same. 

[fiddler49]

I'm not an expert on cable backing. I've tried it before by twisting the cable with short levers while the cable is flat against bow back.It didn't seem to do much. You could make lots of bridges, taller bridges , shorter bridges, skinny bridges. Not much written about this. I haven't seen any cable back bows on PaleoPlanet or here since I've been here so you all will have to just experiment like me. I don't measure draw weight past 28"
because I use a bathroom scale with my tiller tree and I have to put my head down near string to read scale,EEk!!!
but I do draw 31.5" using a thumb release. If the bridges are too heavy or too close to the tips they will slow the bow down! The farther away from the bow back the cable is, the more it will stretch when you draw the bow and the more energy it can hold! Dick Baugh says in his article that nylon has about the same elastic properties as sinue but you can over stretch nylon so it looses it's elasticity. Thats what I might have done using the twisters the first time I tried this. Anyway we need more hard science on this subject so get out there and experiment lads!!! cheers fiddler49

[DC]

Neat experiment. I'm wondering if you had left the cable a little farther from the bow when you tied all those half hitches. Like you said, when you tried it with the cable flat against the back it didn't work that well. If the cable had gone from the handle to the bridge to the anchor so the cable was straight you could have pulled it a little tighter. Maybe even pull a little reflex into it. Just spitballin', I know nothing about this.

[bowmo]

Hows the nose with the blocks? I feel like I would have to add a bit of leather in between them.

[fiddler49]

DC, I tightened each of the 7 strands before I put the bridges under the cable. The bridges tightened the cable even more and the half hitch lacing tightened the cable extra tight.
Bowmo, A bit of leather under the bridges is a good idea, especially with the crown on a stave. One thing to remember round out the sharp edges on the bridges or you might cut the cable or dent/crush the bow wood.

[nakedfeet]

Those bridges aren't causing the flat spots or hinges. I say that only because you can see them at brace all the same.

I think we'd have to see the bow braced without the cable backing to judge that. My thinking is that the tension is going to change even at brace.

[Spotted Dog]

This makes me think of the Penobscot bow from Maine . The double bow.