Sunday, September 20, 2020

Cabin #6 Re-Assembly Begins

The dis-assembled cabin is at the other end of my 6 acre woods. Logs for one round are loaded onto the trailer and brought to the re-assembly site. Just as luck would have it the Sky Hook line runs right through the center of the cabin. Logs are rigged here with a sling or set of log hooks and lifted off the trailer.

With the sling positioned so that the log balances the lift is made

The lifted log is then pulled into the cabin. To keep the lift as low as possible I left the header of the door frame off.  Back and front logs are the longest and heaviest. The lift makes light work of placing them right into position on the wall. Because there is no left or right movement of the hoist side wall logs require a support plank to be placed parallel to the long cabin wall as a temporary support. The hoist is removed. The logs are then inched along with one end on the wall and one end on the temporary support until they reach the side wall where they finally sit. 

The half dovetail notch area on each corner is covered with a 2" thick pad of fiberglass insulation. This seals the joint. Later the excess that sticks out will be cut flush to the surface of the log and become invisible.

Window frames were set in place using the hoist.

Then they were braced level and plumb. A little side note here. When I went to the local lumber yard to get the four 10 foot 2x4's the guy said, "Gees lumber prices have really gone up." I took it as just shop talk. Then I saw the bill $41.78 !!! Imagine building a house.

I adjusted the height of the anchor by about 4 feet to be able to clear the door header. Looks like the force on the tree anchor is pretty high. Lucky this is the last of the 7 inch thick heavy logs. From here on up the logs are hewed 6 inches thick. This will reduce their weight to less than 200 pounds max.

It's not all work. Took a break and enjoyed a nice fire "in the cabin" with some friends. 

So this is it. Three days work and first level is back together and tied together with full length logs in round 8. For an extra measure I drove in screws in the top corners to make sure they did not move or shift as I begin work on the loft level walls.

Friday, September 18, 2020

Rigging the Sky Hook

These pictures are going to be in the reverse order I wanted them to be in but the Blogspot people have changed the program as to getting pictures up loaded and this will have to do until I learn how to move them around.

The true test a 300 pounder is lifted off the trailer and heading to a landing on the back wall of Cabin #6.Coming off the trailer and ready to make the move to the cabin

Not wanting to find out the hard way if my calculations and the system was worth of the task I decided to test it out with one of the smaller logs first. Chicken that I am.

If you have ever tried to stretch out a line you know that pulling it starts to get pretty tuff as the line starts to straighten out. Especially with a 50 pound hoist on the line. A 5/16 inch cable with a 1900 pound capacity was used. Two ton come-a-longs were used to pull it. As they only had a 10 foot cable one was used to start the pull and a second one was used to finish the pull. 

To allow the 1300 pound hoist be able to move along the cable from the trailer to the cabin wall I installed a set of 1 1/2" cast iron pulleys in the hangers. It was tight but with a washer spacer below the brackets the cable cleared the top of the housing. I also had to extend the wiring to the remote control switch as the hoist would over 12 feet. This was tricky as it needs four wires to make the circuit for up and down control.

Here is the drawing of the layout for the Sky Hook

Here are the details on the calculations and the web site I used to determine the forces at play.

In closing all I can say is that this experience allowed me to learn a lot about rigging rope for a system like this and opened my eyes to the engineering that goes into lifting loads with cranes and such. There is plenty of information on the web about this if you want to learn. Finally,  this experience answers the question I asked every day in some the the more difficult classes I had in high school and college, "When am I ever going to use this."