special order bushing for rope wrench

surveyor

surveyor

Been here much more than a while
Location
NC
I am thinking of having my machinist make a bushing for my singing tree rope wrench, in either steel or aluminum bronze. It would work with the removable 5/16" quick release pin and would be machined from 3/4" stock in the form of a sheave with 1/2" inner dia. If others are interested in such a bushing, I would ask $10 + shipping per bushing. I would need to make at least 5 in the aluminum bronze in order to break even on material costs alone.
 
Could the bushing be put on the non removable pin to take up the space? It would seem to have the same effect (taking up the extra space) and you wouldn't have to worry about dropping it. Just a thought.
 
The bushing would just slip onto the 5/16" pin and could be placed at either friction point either with a 5/16" bolt or pin. It would be machined like a shallow sheave with 3/4" outside dia. and 1/2" inside diameter.

Chris I will have my machinist make one for you also in steel and PM when I ship it.

Gordon
 
[ QUOTE ]
The bushing would just slip onto the 5/16" pin and could be placed at either friction point either with a 5/16" bolt or pin. It would be machined like a shallow sheave with 3/4" outside dia. and 1/2" inside diameter.

Chris I will have my machinist make one for you also in steel and PM when I ship it.

Gordon

[/ QUOTE ]

The way you are stating the measurements sound messed up (incorrectly stated).
A bushing with an inside diameter of 1/2" would be sloppy on a 5/16" pin and why a 3/4" outside dia.? I thought the Rope Wrench had a 1/2" diameter at the friction points (pin centers). Sorry in advance if I added any confussion.
Scrat
 
Maybe a drawing will help. I have contacted my Machinist friend and he is temporarily out of commission. I will post again when I have a few examples in hand.

001-2.jpg
 
Surveyer,
Thanks..that helps us machinists understand much better.
Does the original top friction pin on the rope wrench have the concave radius as depicted in your drawing?
 
the original is a round barrel pin. I have made contact just now with another machinist friend, and he says he will be able to make a few for me. I have ordered some aluminum bronze stock so these bushings are back on track.
 
Still a little confused but let's see:

the new bushing will fit snuggly on the pin (since both are 5/16th) and together they will rotate as rope is run through the RW?
 
Thing about the rope wrench for as far I have used it now (1 week) is that is gives extra friction so your knot handle likes on a DRT system.

If you converse the point of friction into a lesser friction with bushings etc. it won't work the same and the knot will take extra force/heat. The whole point of the rope wrench will be gone IMO

Or is this just a stupid thought.....

Climb safe
wouter
 
wouter - I think that is a reasonable thought. But i don't notice that having a bushing changes much for me.

THe removable pin itself will spin in place until the wrench is fully engaged into descent, at which point it will "lock" into place. I have a bushing on my removable pin and thought that it spinning as well may be an issue. But I don't notice that it is an issue. I actually can't tell yet if the bushing itself spins when I am into full descent - it is polished smooth and it is difficult to see when above you! In any case, it doesn't seem to affect performance for me, so I haven't tried very hard to figure it out. The other bar of the wrench provides just as much friction as usual, so you are really only potentially reducing friction on half of the wrench's friction parts. The bushing is for folks who want a larger bend radius on the pin (I'm not sure how much that matters, either!)

surveyor - looks like a cool bushing - I'd give it a go.
 
In my experience the upper bushing and or pin will rotate but it does not seem to make that much difference. I would recommend putting a sheave at both friction points, just clamp the lower sheave from turning with a 5/16" bolt and lock nut. Having a lower sheave (held) should increase the friction slightly at that friction point and help preserve the roundness of the rope, however most of the friction will be at the "sides" of the rope facing the pivot points.

Nothing ventured, nothing gained.....
 
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