Construction Journal Entry Week of 10/11/15

10/13-15/15 I went up to Camp Serendipity for 3 days: Tuesday through Thursday.

On the way, I stopped and played a game of checkers with Uncle Charles. I got beat bad! At the end, he had eight checkers including two kings, and I had nothing. If his mind is slipping, then I hate to think about what mine is doing.

The drive over the mountains was gorgeous. The leaves were at their peak and there had been some rain so they were brilliant in the sun. I arrived at Camp Serendipity right about noon. I was greeted by Roxy, another neighborís dog. I treated her to a couple dog biscuits.

After moving my gear in, I watered Brian, the giant sequoia tree, and then had my lunch. After lunch, I went into the woods and checked on the sequoias. They were all doing well and looked to be ready for winter. When I returned, I had my usual nap.

When I got up, I took the spread sheet I had brought with me out on the front porch. The spread sheet had calculated the cumulative distances out for each of the stair treads as well as the cumulative riser distances. Using a tape and these numbers, I marked the horizontal 2x4s and then cut a small notch in the edges of the 2x4s alongside each mark. These notches will hold the strings of plumb bobs so that they are in the direct line for the noses of the treads that will be placed below.

On Wednesday I began installing the fifth log tread from the bottom of the front staircase. I hung two plumb bobs from the 2x4s overhead in the notches corresponding to that tread nose. Then I built a suspension system to hold the tread above its destination in a position for scribing. The system was designed to allow me to independently adjust each of the six degrees of freedom of movement of the tread.

To build the suspension system, I started by screwing a rectangular piece of ľĒ plywood to each end of the tread blank. The plywood pieces were each then clamped to a vertical board that rested on the ground. That more-or-less fixed the first three degrees of freedom.

The horizontal, i.e. along the long axis of the tread blank, degree of freedom was not critical because the tread blank was oversize and the ends would be cut off later anyway.

The two vertical degrees of freedom, one on each end of the tread blank, were fixed temporarily simply by the clamps. But each one could be adjusted independently by loosening the clamp, adjusting the height, and tightening the clamp again.

The fourth and fifth degrees of freedom, those perpendicular to the first three, were fixed by clamping a 1x2 to each of the vertical boards and the 1x2s were fixed at the other end by screwing them into whatever was handy to use as an anchor. In one case, I screwed the 1x2 to a tread higher up on the staircase, and in the other case, I screwed the 1x2 to a log slab that was stored under the porch and just happened to be in a convenient spot.

The sixth degree of freedom is the angle of rotation about the long axis of the tread blank. This was a little tricky because in order to rotate the tread, both clamps holding the ends of the tread up had to be loosened. But that would then mess up the vertical alignment of each end.

That problem was solved as a by-product of the solution to another problem I encountered before I got that far. I discovered that it was a tricky business to adjust the height of even one end of the tread. When you loosened the clamp, the plywood sheet did not easily or smoothly slide in the right direction. Instead it would let loose all of a sudden and I had to man-handle all that weight at once while attempting to re-tighten the clamp.

The solution to that problem was to start high enough so that the necessary adjustment to the height involved only lowering the position of the plywood with respect to the vertical board to which it was clamped. To make an adjustment, then, I would first measure how far down I wanted to move the tread. Then I would clamp another clamp to the vertical board just under the bottom of the plywood sheet leaving a gap the size of the amount I wanted to lower the tread.

Then, when I loosened the top clamp, the one holding the tread fast, the tread would slide down and stop when the plywood hit the lower clamp. Then I could re-tighten the top clamp and the tread height would be correctly adjusted on that end.

The actual height of the tread was not critical as long as it didnít hit the stringers below. The only thing critical about it was that the tread needed to be horizontal. So to get it just right, I simply lowered whichever end was too high until the tread was level.

Once the tread was leveled in this way, either, or both of the top clamps could be relaxed a little without having the tread move because the weight of the tread was borne by the bottom clamps. And, with both top clamps relaxed like that, the tread could be rotated about its axis, sort of by using the lower clamps as axles or fulcrums, until the top of the tread was level perpendicular to its axis without messing up the level along the axis (too much). At least this method allowed enough control to get the tread level in both directions.

Once the tread was leveled in this manner, then the vertical alignment of the ends of the nose (the fourth and fifth degrees of freedom) needed to be tuned up a little. These adjustments didnít affect the level enough to notice.

With the alignment done, the tread blank was snugly clamped into position so that it was directly above the place on the stringers where it needed to go and its tread surface was level in both directions. It was now ready for scribing.

It was just about exactly noon when I succeeded in getting the tread in this state and I was excited. Instead of stopping for lunch at this point, I was so eager to try out my new scriber, that I went ahead and scribed the tread and stringers before I stopped for lunch and a nap at 1:30.

I had almost decided to buy an expensive scriber since the two staircases and the porch stoop will require a lot of scribing. The butt and pass method of building the cabin, unlike all traditional log building methods, does not require scribing at all. (I scribed the logs that I had flattened for beams and purlins, but that did not require the same kind of scriber you need in order to scribe the intersection of two logs, like my tread/stringers or the corner joints on a traditional log structure.)

But before buying a scriber, I thought about making my own and I came up with such a promising design that I went ahead and built my own for cheap and with very little effort.

The scriber is built by bolting two long wood shims together in the middle to form a scissor shape. The angle between them can be adjusted by loosening the bolt, and it can be fixed by tightening the bolt.

On the slim end of each shim, I taped a fine-point Sharpie pen with the points outward. Those would be making the scribe marks.

On the thick end of each shim, I tightly wound a short length of AWG 12 bare copper wire so that an inch or so of it stuck out beyond the end of the shim. One of those wires, the one that would be the top one, stuck out fairly straight and it had a small loop in the end. The wire on the bottom was a little longer and it was bent into a right angle right at the end of the shim, then in a little less than an inch beyond that, it was bent in a bight so that it made a 180į turn and came back to about the center of the shim. Here it was bent into a circular loop about 3/8Ē in diameter and perpendicular to the plane of the scissors.

To complete the scriber, a piece of masonís string was fastened to the top shim, then threaded through the small loop in the end of the top wire, from there it went down through the bigger loop at the end of the lower wire, and finally was tied to a 3/8ď hex nut which serves as a plumb bob. The nut hangs only about a half inch below the wire loop.

Thatís it. It is ready to scribe.

The first step in scribing is to set the distance between the two pen points to the correct size. This size is determined by how far the upper log (the tread) has to be lowered in order to end up in the correct final position. In my case that is easily determined by measuring the distance from the surface of the suspended tread to the overhead 2x4 and subtracting it from the calculated cumulative riser distance for that particular tread. I made a gauge for that calculated distance by driving a long finish nail into a 1x2 exactly that distance from the end of the 1x2. Then by hanging the gauge from the overhead 2x4 by the nail, I could just set the scriber by having one pen tip at the tread surface and the other one at the bottom of the gauge 1x2.

With the scriber set to the correct angle, the nut is tightened and the scriber is calibrated. The next step is to adjust the length of the string so that the hex nut hangs just about a half-inch below the lower wire loop. Any time the angle of the scriber changes, the string length needs to be changed to match.

Next, I need to adjust the vertical alignment of the scriber. For that I select an inside corner of two walls in the cabin that I know are both exactly plumb. (I think that every drywall corner in the cabin qualifies.) I hold a partially folded piece of aluminum foil in the corner and then stick both pen points of the scriber into the corner and onto the aluminum foil. That holds the foil in place and the foil keeps the pens from marking up the wall.

With the scriber in that position, I know that the two pen points are in an exactly plumb line. While holding the scriber still in that position, I bend the top wire back and forth until the nut below is holding the string near the center of the lower loop. Then I bend the lower wire a little in or out in order to get the string to hang exactly in the middle of the wire loop. If it started out badly out of alignment, this process may need to be repeated. But it turned out to be an easy and quick operation. That is because each wire controls just one axis. If the alignment is ever suspected to be out of whack, it can be checked and re-aligned quickly and easily this way.

When the scriber is calibrated and aligned in this way, the next step is to scribe the wood. That simply means to slowly move the scriber toward the logs so that each pen point comes in contact with one of the logs and the string is centered in the wire loop. Once both pens are in contact with wood, then the scriber is slowly slid in one direction or the other always keeping the points in contact and the string centered. It is surprisingly easy.

Since the plumb-bob hex nut is so close to the wire loop, it canít swing very much, so that when the scriber is aligned vertically, it doesnít take long for the string to quit swinging and you can fairly easily keep it centered in the loop as long as you make slow and correct moves with the pen points. It took me an hour and a half to calibrate and adjust the scriber and to scribe both the left and right log joints. Most of the trouble was in contorting my body so that I could see what I was doing and be able to manipulate the scriber. Iíll probably get better at it as I get experience and as the clearances around the work get bigger.

When I got up from my nap, I started notching the tread. I got out a couple sawhorses, gassed up the chainsaw, and started cutting. I was conservative in my cutting, knowing that I could cut more off later but if I cut too much, I couldnít easily add it back on. So when I had the preliminary notches cut, I carried the tread back up to the staircase and tried it out. That tread is pretty heavy so it is a lot of work manhandling it and carrying it around. I was always careful.

With the tread in place, of course it didnít fit, but I could see where wood needed to be taken off in order for it to fit better. But by that time I was so tired and sore that I quit for the day and went in for the night. I was a happy man, though, very happy to be working with logs and my chainsaw again. One thing I noticed was that my chainsaw seemed to be a lot heavier than it used to.

On Thursday morning Robert called telling me about his recent project of cutting down some very big and dangerous trees on the Lake Wenatchee shore. He told me that he still plans to continue the work at Camp Serendipity once he gets some other things done.

After breakfast, I went back outside with my chainsaw and refined the notches in the tread. After the notches got close to being right, I switched and began using Rasputin instead of the chainsaw. By the time I quit for the week, the tread was still not in position. It needed to rotate backward by several degrees but I was out of time and out of energy.

About the time I started bringing in my tools and fixing my lunch, Earl called and invited me to go with him to have some fun either kayaking or gold panning. He had forgotten that this was the day I was going home, so I had to decline his invitation. I left for home by about 1:00 very happy with the progress. I drove past Robertís work site and looked at the trees he is cutting.

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