These are images of cut #4 on the next day, still standing, which proves the through-bolt method works well. I was incorrect in thinking that the locking mechanism failed. It did work, but is quite mangled as a result. Going forward my strategy will be cutting irregular shaped pieces (think L-shape) and letting part of the ice rest on the top surface in addition to a chunk still in the water. Another option is a "lasso-method", which would require someone to connect a chain (looped over the header of the gantry) to the slab of ice as it reaches the top of the gantry crane. I think this would actually be doable since the winch is moving very slow as the slab is pulled up high.
The locking mechanism sucks. I think the problem is that I integrated it within the winch itself, so when I load the winch with 2000 lbs of ice the internal stresses are so great it binds the moving parts. My plan is to add an external 'clicker' that will bolt to the gantry crane, and be independent of the winch, but still lock the spindle.
Cut #4 was pretty successful. In addition to the typical lag bolts I use, I put two through bolts in the slab with butterfly clips on the end, which keeps it from pulling back out. Although the winch lock failed, I think the slab was cut long enough to bottom out, stopping the free-fall.
I'll check on things in the morning and see if it held up. I'm now trying to time my cuts towards late afternoon, so the evening drop in temperature works to my advantage. The sunshine causes the bolts to pull out more easily.
This is a photo I took of my last failed attempt. Notice the shadow of the slab creating a third space within the ice, rendering 2D space into an (almost) 3D space. This is part of what I'm after.
After leaving the slab from Cut #3 suspended in the air, I came back the next morning to find that it had fallen back in the water at some point. The lag bolts had come loose, which is now another wrinkle to iron out.
I decided to approach cut #4 with a different strategy, cutting a long and narrow chunk of ice hoping that it would sink into the bottom of the pond, relieving the load put on the lag bolts while waiting for everything to re-freeze. I don't have video of this because I filmed from the beginning and this piece took twice as long to cut, so my memory card filled up at some point during the process. I was able to get the piece of ice almost 9 feet out of the water, but the locking mechanism had failed after Cut #3, and the winch free-wheeled back down, ultimately breaking the slab. But a small chunk remained, so I left the rig hooked up to see what happens over night.
The slab broke into several pieces, and I took some interesting photos of the various chunks interacting with each other. I slid one piece under the remaining slab still attached to the line, and got some strange 2D and 3D effects happening under the water, which really gets at an 'other' space.
I spent the whole weekend working on the lock mechanism for the winch. I finished it with only a few hiccups, and was eager to test it out. I also decided to make a big purchase and buy a stihl chainsaw after the problems I had with the one from lowe's (which they took back, no questions asked).
The ice on the pond is doing strange things. Large cracks (as in up to 1/4") are forming throughout the surface, and it's happening in real time, like a glacier on fast forward. At first it's alarming and it sounds like you're going to fall through, but considering how thick the ice is there is no danger. The noises range from typical crrracks, to odd rubber band sounds, and as Jason pointed out on the site visit last friday, like someone getting punched in the stomach.
The new chainsaw worked pretty well, although it did bog down here and there. Mireille put me in touch with a friend of hers who works on the ice hotel in Sweden, and in the photos it shows him using a huge Stihl chainsaws, the ones that go for over $1000. I settled for the $339 "farm boss", as the salesman assured me it was the most popular all around Stihl. He also showed me a 30 inch diameter tree trunk that he cut through. Okay, sold.
Test #2 didn't work out so well, as I'll let the video explain:
The failure of the mini-gantry crane was due to a poor connection I made using brad nails. I watched the movie in slow motion the way we did in structures class, and I saw the exact piece that went...and thought about it and remembered 'hey, I never screwed that in'. In part, because I didn't think it was going to be a significant factor in carrying the forces, but once that weak link went, it was all over.
One upside to this failed attempt was that I learned just how thick the ice was (I measured 10 inches) so I felt confident about driving my car out on the ice to load up my stuff....confident enough to drive very slowly with the rear hatch and the drivers door open in case I had to jump out, but after five minutes I was very sure about the laws of physics and drove all over the pond, and onto the different washouts from the edge of the gravel pit. And I'm sure my car was the first one to ever do this on the nudie pond, thanks in large part to a small road my Dad put in at the mouth of the pond.
I went back to the studio and started ripping the 2x10's down into more manageable sizes, and now I have a bigger, beefier gantry crane that towers 11' high and has stronger connections. I'm going to paint it white before I take it out to the pond. Transporting this thing will be crazy. It comes apart in three pieces, but it's still big and heavy. The justy will prevail....
I took apart my winch to hybridize a locking mechanism into the spindle. I made some drawings of it in Rhino, and then cut out the pieces on the waterJET.
You can see a video of the water jet here. It's not too exciting, except when it 'pierces' the metal before it begins a cut path -that is the moment in the video when it starts spraying.
The next step was to tap the threads and weld everything together. This year the metal shop got a nice TIG welder, which does an extra clean job on regular steel.
