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Posted

I’ve used the Grivel Easy G and the Charlet copy of such. I prefer both over the lockdown, as the tool doesn’t spin if when dangling from the wrist (which in effect shortens the leash). All three suffer from the fact that if going to a heavier glove, the leash in effect shortens based upon the increased circumference of the gloved wrist (an android is only affected by the increase in radius). There is a simple improvement that can be made to all three as well: add a small slider ABOVE the sliding cuff. When climbing snow or doing anything where the leash isn’t tensioned for long periods, the slider can be moved to lock the cuff in a closed position. Thank ADE of cc fame for the idea.

 

As for the Android, I love em and hate them. They are very secure, and seemingly fragile and prone to fuck-ups. Punching a tool into hard crust for a while, is potentially going to destroy them. Breaking a pick on an androided tool and trying to switch to a third with the android cuff still on, is just a barrel of laughs (don’t ask). It’s also difficult switching hands quickly (snow) with androids. Finally, if you do need to go gloves off, good luck getting out of the cuff, or better still, getting back in.

 

No doubt someone out there is asking why would I want to do easy climbs with an androided tool? My answer would be why would I want to switch tools or leashes every time I faced an easy exit.

 

It’s all gear.

 

Q: Do you own your gear or does it own you?

 

GB

 

Posted

I have a set opf lockdowns for alpine climbing and they're mearly "OK". They're another example of a BD product that needs a couple more revisions to be called "good".

 

The main problem being that the buckle that's supposed to stop the leash closing too tight around your wrist is too small and fits through the tube of fabric. It needs a bigger buckle or better tollerence on the fabric stitching. I tried tying a knot around the buckle to make it larger but this only helps a little.

 

Posted

I've experimented and I like the BD lockdown too. Simple and versatile, easy to get in/out of, works for alpine. I don't like the limited reach with androids while still attached to the tool and don't always like the option of having to unclip and risk loosing the tool. To each his own.

Posted

did you fabricate the spring clip thumb part too?

 

is the stud milled out of the same piece as the plate or

is it riveted in? How is that piece of webbing that wraps

around the shaft below the stud plate connected .. or is

that just webbing wrapped around a hoseclamp?

 

the keyhole slot that slips on the stud doesn't have much

difference in size between the wide hole and the long slot,

how much actual overlap is there on the stud? Judging from

the wear marks it looks like less than a millimeter? Seems like

this is where the actual weight-bearing is when the leash

is in use, are you concerned about it getting worn down and

a sloppy fit?

Posted

Yes every part of the leash was fabricated from stock. All the steel is 304 (including the bolt) with the exception of the button part of the clip, which is 316 and the spring, which is just regulr spring steel. The stud is threaded 3/8-24 and it is loctited into a shallow tapped hole in the plate. The webbing is as you describe, it is 9/16" tubular with about an inch worth of the "tube" part removed to protect the underside of the screw part of the clamp. I added this as an afterthought because the stud plate was touching the composite surface and I was worried about getting it scored/cracked. I had plans for a fourth revision which added a layer of teflon to the back of the stud plate but I ran out of time and haven't gotten to it since last season.

The tolerance you speak of is exactly the reason this design went through three revisions, there is a delicate balance between the size of the stud, the groove where the plate fits and the size of the keyhole slot. Basically it is weighing tradeoffs between the ability to slide the clip on/off, how well it rotates and how tightly it fits, and then all of these factors when the tool has been at -30F for a few days... The clip bears almost all the weight straight down, on the long axis of the clip so any wear that occurs will be on the top of the slot, not the sides. I do have drawings and specs on the dimensions of the stud and keyhole, as that was my biggest problem. The picture of the keyhole is badly blurred, the hole gives 0.005" clearance around the stud face, and -0.015" on the back side of the stud so you cannot clip "past" the groove. The slot has 0.020" clearance around the groove which allows a freely rotating but not loose fit. The difference between the hole and the slot on the clip plate is something like 0.360" vs 0.250", and is more than adequate even if it were to be weighted sideways. The clip plate is 0.120" 304 and remarkably stiff and tough. I'll look for the CAD when I get home if you are interested.

Posted
the hole gives 0.005" clearance around the stud

face, and -0.015" on the back side of the stud so you

cannot clip "past" the groove

 

clever! I hadn't noticed or thought of this but I see it now.

 

did you experiment at all with making the stud end more of a

bullet shape or conical, so that your aim needn't be so precise

when you are reclipping the wrist piece?

 

did you do any testing to see how much load you could hang

on the wrist loop before the whole thing breaks? My guess is

that the failure mode would be the stud would pull out of the

threaded hole.

 

I guess you are manually machining all this? so it would be

a drag to spend time turning some out just to do destructive

testing yellaf.gif

 

 

Posted

"Finding" the stud is actually not an issue. I thought it would be and my first version of the stud had a tapered head for about half its length. Just rounding it and sanding works just fine and I think it looks a little cleaner.

I did do some testing with my scrap, I milled a keyhole slot in a plate with a hold in the bottom to tie off to, it held me jumping up and down in my aiders verticaly, and the clip plate bent 90 degrees loading it sideways with almost no damage besides surface scratching to the sides of the plate. The plate held body weight before bending but upon bouncing it started to bend and ended up as an "L" bracket that then withstood more vigorous bouncing.

 

We are talking 304 stainless with about 3 full threads of 3/8-24, this should hold at the very least a few hundred pounds straight out and a few thousand easily loaded on its side as it is. The stud plate is 1/4" thick. The way I attached the stud:

 

 

-3/8" 304 bar stock, about 4" out of the lathe face

 

-turn the groove, then reduce the stud face diameter

 

-shape and clean the stud face

 

-turn a groove 0.100" wide to 0.280" on the back side of the stud

 

-cut off at 1" from the stud face

 

-thread the back side of the stud (now about 1/2" to the small groove)

 

Now you are left with a profile like:

 

stud face

--------v

 

---_--_-\

\\====| <-- on center

 

^-- threaded end

 

which will fit neatly into a hole tapped about 90% clean, so when you tighten it, it feels like pipe threads locking together. Add some red loctite before wrenching to ensure it doesn't move, then grind the back side of the plate flat.

 

The stud and plate are easy to make many of, the clip button was a simple nibbler job with some bends and two holes for the pivot. The clip plate was the biggest pain, with the two wings to bend for the pivot and the three rectangular slots for the webbing to thread through (can somebody say 1/2"x0.050" slotting saw?) BTW, 9/16" tubular if I recall correctly will cinch tightly in a ladder-lock arrangement using the 0.120" stock with three slots of 0.060, 0.060 and 0.130. I wasnt about to cut 0.120" 304 with a 0.050" end mill... For the testing, I just made the keyhole for my own sanity.

 

It wouldn't be time-effective to CNC any of it besides maybe the stud, but that only takes about 3 minutes per stud once you are set up for it. Would take longer to set up a thread cycle on a CNC lathe! Even if you did mill all the parts on a CNC you still have to bend them and grind the stud off and clean up the sides of the clip plate.

Posted

That may be, but you have to remember that leashes are not a fundamental part of the climbing system, merely an aid tool. You can tie a leash that will be sufficient to climb most anything out of 12' of 1" tube. My alpine axe has been leashed like this for years and it is light, secure, and comfortable. Two spins of my wrist "locks" me in and the wrist loop slides up and down the shaft so when I drop it or need to grab the pick for whatever reason it is right there. A leash failing isn't a big concern for me on technical ice. Thats what the third tool is for...

 

I've also made industrial equipment that gets hammered way more than my leashes do out of similar materials and to the best of my knwledge they are all still in service.

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