Compact Bulldog Bone

Sure Caleb, you will have to give it a try. I will be gone to the airport this morning, but will be back this afternoon.

Eric it will work as you describe, it helps to have the slack tending pin installed.
 
Just to add that well I love this thing - it's so "simple" (I mean elegant I think), getting it on and off is very quick!

I think I'll have to get some more line though. My "cheap" 11mm is too soft and it slips quite quickly through the Bone when SRT - maybe I'm too heavy. It's quite a "loose" rope and comes through the bone very flat - but isn't milking. I made an extra 20mm sleave for the top arm roller and that helps a bit, and makes my Responce respond really nicely - much smoother than the stock 16mm roller. The skinny rope works great DdRT in bone.

The Responce is specified as 11mm rope, but its quite solid and in the calipers looks more like 12. Unfortunately the Responce is fairly short so I'll see how I get on with using it for SRT and the other stuff for DdRT. I'd love to splash out on some 12mm blue tongue...

Thanks Gordon!
 
Oceans - from my quick play today, it tends for a limb walk really nicely - and works great with a 3:1 haul back. I suspect it would be even better with a pin in the outside holes on the lower arm, but that would make it slower to get on and off. No slic pin supplies this side of the pond :(
 
Thanks Mac & Paul. By looking at the design, I would think that a pulley out on the end of the arms would make the lower arms compress against the spine when the rope was set up in a ponytail redirect or 3:1 haul back. Without the roller, I would think the unit would collapse and you'd be focusing the rope onto the lower chain bollard.
 
oceans - you are probably right. It might help for normal haul, but for a haul close to the working line... hmm. It does work well as it is.

EDIT: I put a pin in there... and it makes very little difference - certainly does not imede a 3:1 haul.
 
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Eric, you should not put a pulley or roller out at the end of the lower arm as this does interfere with the slack tending release, however, just the slick pin (without a sheave or roller) works to create a sort of virtual radius pulley as the Bone collapses and tips when being tended for slack or in a mechanical advantage haulback setup. Eric I plan to send you out the part you requested. Thanks, Gordon

IMG_0957_zps1b1b6010.jpg
 
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I just made up a couple of 12.5mm sheaves for the two pins. Made my skinny rope work ok, albeit with just me sitting on a board - no harness, boots or other kit.

Still thats promissing. I also had my 20mm top roller sheeve on at the time.

Oh and I also reversed the top two arms so that the rope guide grooves are on the outside - I figured that would lessen the ability of the rope to flatten and not grip.

Gordon suggested trying large washers on the pin either side of the rope - It had some effect for me, but they would not sit straight and I did not like that they were scraping the rope and that they could jump up and out of the slot and sit on top of the arm - which would affect the operation of the device.
 
Paul, I am suggesting that the fat alumiunum washers do indeed stand on top of the arms and clear of the rope, in order to create more of a bend in the skinnier rope.
 
What's cool to me is how mechanical hitches are really a lot like rope hitches. There is a ton of ways to tie your knot. I keep on thinking of tinker toys and legos. It's great stuff.
 
Aye. I still want to play with an RR.... and compare ;)

EDIT of course the comparison with lego and tonka falls short when it comes to the severity of experiments that go wrong... :D
 
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