Making a (endless loop) string jig

Corax67

Well-known member
I made a Flemish twist string jig about 12 months ago from a piece of reclaimed mahogany & plans off the web - this has worked well with over 20 strings made & shot to date.

I would now like to try my hand at making recurve strings.

Club has an EXE jig that our equipment officer uses to make club strings & give demos but at ?185 plus associated import and delivery charges this is way out of my league.

I have however seen the "table top" jig in the picture below on an American website and as I have access to box section, steel plate & bar stock and a welder could probably make a reasonable facsimile.






My concern however is that is that whenever I have seen such strings made a lot of emphasis has been placed on tensioning the string before serving but I fail to see how this might be achieved with a non-adjustable jig such as the above.

Is tensioning really crucial or would such a jig be effective ?



Karl
 

Rik

Supporter
Supporter
Personal experience: tension is a problem with an endless loop string because it increases as you wind it. That places strain on the jig and means the tension is not even.
One strategy is to wind with decreasing tension to try and keep it approximately even. Which means you need control...

I've found it easier to control tension by winding on using string material on a serving tool. It's not the jig per se. Though a more rigid jig, lets you apply twnsion more easily.
 

Corax67

Well-known member
Thanks Rik,

That's the the beauty of the EXE because it is built very robustly with a heavy duty screw adjuster that locks off.




Karl
 

geoffretired

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Supporter
My old home made jig isn't too rigid, but the strings can be wound on with equal tension; though not high tension. The trick is to wind on so that the second wrap round does not hang down compared to the first, nor does it cause the first wrap to go slack by wrapping the second one, tighter. That pattern has to be followed to the end, so you don't make the last one too loose or tighter than the previous ones.
I have free spinning rollers on each post so the finished loop can be wound round like the track on a tracked vehicle. As the whole loop is rolled round, each section gets a chance to be free from the friction generated at the posts. By gently pulling each half away from the other, at a point mid way along the length, any tight parts get a chance to even out compared to any loose ones.
I made a stretcher that I use after the wraps are finished; but I just use it to neaten up the finished look. A friend of mine twists the loop and fits it to his bow. Then leaves it to settle, and later puts it back on the jig to serve.
 

Corax67

Well-known member
Thanks Geoff - that's the second time I've heard about roller top sections on the arms for running the string around, think first time was a YouTube video. Can probably fabricate something like that in the machine shop in work on the lathe.




Karl
 

dvd8n

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Supporter
AIUK Saviour
It does seem like a high price for what is essentially half a jig. It looks like they tried to save money by getting rid of the bar and adjusting mechanism but putting all the cost back with the clamping mechanism. I'll accept the point that it would be waaaaaaaaaaaaaaaaaay easier to store though.
 

dvd8n

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AIUK Saviour
My GasPro has rollers on the top of the posts. Although they are turned aluminium, they look for all the world like little empty thread bobbins with a bolt through the middle. Have a look and see what's in the sewing box :)

There are no bearings or anything; it doesn't look like any are needed. If you're not happy that the tension is even you can give them a little twist back and forth and it seems to all even out.
 

geoffretired

Supporter
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Looking at the pictures, the clamp idea is quite good for saving space etc. What I would do, if you are thinking of making a similar one, is change the posts.
If you imagine them turned into the four in line positions, the one where we start the winding on, the tension on the posts is being resisted by the joint at the clamp, and that looks like a weakness in the set up.
I think it would be better to have the cross bars that hold the posts, actually in contact with the wood, and have the clamp fitting over the bar not under.
That way, the cross bars won't tend to tilt on the pivot.
 
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