Compact Bulldog Bone

I did some work on my BDB today. The first picture shows the finished shortened upper arms which are now identical to the bottom arms except for the end buttons. It now has a notch like on the bottom arms and some removal of the aluminum on the inside for the rope channel. The second picture shows an advancing tether made from a short nylon strap that is held on by rings. I also made a new spine out of 7075 T6. Not only is this far stronger but with no tending hole it can be rotated so that it has 4 different contact patches, should last a long time.

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I have not used the tether yet so that could possibility need some tweaking but everything else works great.
 
DSMc said:
I did some work on my BDB today. The first picture shows the finished shortened upper arms which are now identical to the bottom arms except for the end buttons. It now has a notch like on the bottom arms and some removal of the aluminum on the inside for the rope channel. The second picture shows an advancing tether made from a short nylon strap that is held on by rings. I also made a new spine out of 7075 T6. Not only is this far stronger but with no tending hole it can be rotated so that it has 4 different contact patches, should last a long time.

View attachment 29205 View attachment 29206
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David, that is absolutely gorgeous! You've furthered an already beautiful piece of art. I'm about to do something with mine, but there are just so many options. :) I'll most likely be shortening all the arms. I really want to add a scallop to the upper arms and deepen the one in the lower arms.

I'm getting such good control with everything, and still pushing forth with DSRT, so I feel a bit less material around might be nice. Due to the DSRT, I had the idea to do the safety mod on the upper arms on one, and the lower arms on the other.
 
Looks beautiful David! The strap is so very tidy also, and if need be you could move it to the upper portion of the double joint, just be careful not to transfer weight onto the strap while leaning back. My new batch of Bones also has a half moon notch in the upper arm, and the spine joints are beefier, as is the teardrop where it fastens to the lower arm. along with SS links at the double joint and teardrop attach point.
 
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surveyor said:
if need be you could move it to the upper portion of the double joint, j
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I've done this for tending and the rope just falls through it.

You do have to watch
surveyor said:
not to transfer weight onto the strap while leaning back.
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In my experience it isn't just when leaning back.

You have to make sure you are taking enough weight on the bridge attachment relative to the tending tether.

I currently do this with a 12" tether.

I also found this to be true where David has his strap now too and it seems to tend better "on the upper portion of the double link".


I shortened the top arms but found that it altered the way they sat on the bottom arms, in the collapsed position, in such a way as to create more friction when tending.
 
I'm loving the bungee soft link for tending that little give when sitting back seems to alleviate any issues with the bone not grabbing when transfer of weight from ascent.
 
treegongfu said:
...I shortened the top arms but found that it altered the way they sat on the bottom arms, in the collapsed position, in such a way as to create more friction when tending.
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I find that interesting. It would be nice to see what is going on with yours that is different than mine. The original thought for my shortening of the top arms was to improve slack tending by bringing the top link closer to the spine so the rope path would be more direct when it is in the collapsed position. This works very well on mine with a bonus of much better control and an easier initial release.
The BDB is the most hitch like of any full mechanical I have used. It seems that it may also have the sensitivity, like a hitch and rope, to vary for individual users.
 
David,
The difference may be that mine lacked the nubs on the top arm allowing the top arms to fall between the lower arm friction links.
In your pictures you can see that the nubs don't allow for this

It wasn't a constant drag on tending but it would happen or occur quite regularly on ascent.

I have replaced the arms and made nubs for them and it is nearly frictionless tending.
Treetopflyer said:
bungee soft link for tending
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I found that helped a little bit but, with a chest harness attachment, not so much as to be worth the slightly more sluggish tending.

A 1" hardlink connection to the chest harness allows it to auto tend slack while climbing the tree (ideal) but doesn't pass the "incapacitated" test.

I think I need a bdb spine docking station incorporated into my chest harness so that the spine can be pushed up the rope rather than pulled. Any thoughts?
 
I'll sacrifice safety for speed any day ,its more for the ability to have some give during transition, but with my long arms and when shorten my bridge or even when I don't, the bungee stretches and stays , there's not much sluggish about the setup for me. The bungee is only a three inch loop running up the back of spine not between up between arms and I think will pass an incapacitated test because it will stretch some letting the bone bite the rope so to speak. Along with the chest harness sliding up up a bit. Maybe I'll get all pretend incapacitated and see how I fair . Low and slow
 
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DSMc said:
I find that interesting. It would be nice to see what is going on with yours that is different than mine. The original thought for my shortening of the top arms was to improve slack tending by bringing the top link closer to the spine so the rope path would be more direct when it is in the collapsed position. This works very well on mine with a bonus of much better control and an easier initial release.
The BDB is the most hitch like of any full mechanical I have used. It seems that it may also have the sensitivity, like a hitch and rope, to vary for individual users.
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Did you not also change the upper arm link placement/geometry as well?
 
You can spring load the top links so that the top arm always, automatically engages. Just like the RR. I tried this and it worked but I didn't like it as it made the BDB move like the RR on the rope.
 
Treetopflyer said:
I'll sacrifice safety for speed any day
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I like this devil-may-care approach but I think you might have meant it the other way round ;)

"Did you not also change the upper arm link placement/geometry as well?"

I did try this and found that I didn't like it on cougar as I had to use a larger bollard and I think that undid the advantages you saw with your thicker rope.

I'm finding the stock bulldog bone configuration to be the best and most versatile.

The only thing I'm trying to improve upon is slack tending which it already does much much better than I ever achieved with the rope wrench.
 
I was referring to my typing ability and then the bdb . lol at least you could tell by my post what I actually meant. Shouldn't be buzzing at work ,enough fun and games going on
 
treegongfu said:
The only thing I'm trying to improve upon is slack tending which it already does much much better than I ever achieved with the rope wrench.
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The bone gobbles slack up for me almost from the ground with a monkeys fist or definitely with my chainsaw tied on tail of line of course. When up past twentfive or thirty feet it easily eats slack without any extra weight on tail . When I'm climbing I'll just guide rope towards top of bone to aid in tending ,but its very natural as I hand over hand the line while drawing slack with foot ascendr if angle of body and position dictates I do so. Seems like over thirty feet its just flows right through bone all the while I keep hands and feet on the tree and can climb and don't need to worry about the rope as much as long as the line is fairly parallel to where I'm going if not the occasional flip of the tail under the bone helps send it through or hand above pulling myself up to guide through. I'm thoroughly enjoying the capabilities of the this tool.
I'm still laughing at what an ass I am sacrificing speed for safety I mean I mean fortunately I saved my tail feathers for just such an occasion. Lol
 
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Yeah what a different climb than having to stop to tend and just the approach to movement s when the rope falls right though device. Outstanding performance!
 
surveyor said:
..., and if need be you could move it to the upper portion of the double joint, just be careful not to transfer weight onto the strap while leaning back....
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Gordon, I have tried the upper part of the link for the tether point and, as you say, it works well for the tending part. I do not feel it is a good or safe practice however, because the BDB just will not grab if there is any tension at all on that link. Having it on the lower pivot point works almost as well and is nowhere near as dangerous.
 
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