Sunday, September 29, 2013

The arrival of Cecil

For a long time, my machining capabilities have been limited. I did not have a mill. I did have a lathe. In a lathe, the cutter stays put and the work rotates. So you turn stuff. Candlesticks, for instance. A mill is exactly the opposite. The cutter roates and the work stays put. You mill stuff on a mill. I have a milling attachment for the lathe, seen in previous posts; but the travel is extremely limited. I made do with it for a long time, but finally Fluffy found me a tremendous deal on a Proxxon mill. Now as mills go this is micro. But my little metalworking shop (a hallway) has no room for, say, a Bridgeport mill of any size, plus the floor would collapse under its weight! Even a Chinese cheapo mill is a bit too big, plus it is very expensive. The shipping costs more than the mill!

So as soon as the mill got there, John christened it Cecil B. de Mille.

This baby is very small. Fortunately it comes with a whole lot of gadgets, among them a collet (kind of like a chuck) which accepts Dremel accessories.  So I ambled over to Home Depot when I was in Anchorage, and procured some usable cutters. Above Cecil is milling out some slots for my homemade steady rest for the lathe. I am using a Dremel router bit, which cuts aluminum very easily.

OK, time for a harder test. I must make a stand for my lightweight dial indicator ("clock"), and the hard part of that is milling out the clamps.  First thing I found out is that my Taig milling vise actually fits Cecil. The difference is only a few tenths of mm. BTW, Cecil is metric. And he has zero-able dials! Heaven at last.  One turn of the dials is one millimeter. No more of this "one turn of the dial is 1/20 inch". Lemme see. Ah yes .05 inch. Why these RGU I cannot understand. Why make things so complicated? Why use fractions at all? (Rant off now.)
Anyway, above, I am using a Dremel saw attachment to slit the clamps. Note the Taig vise. I built a table for Cecil. and will sometime soon add a drawer to it. The clamps are brass. But Cecil rips right through it. I am soooo pleased with Cecil. Thanks, Fluffy, for locating this jewel.

Wednesday, September 18, 2013

Snow Spitter 2.0, update

Our snow spitter progresses. Pervious episodes have documented the building of this contraption. Most of this work is John's. I have held tools, passed screws, and found tools. Now we get on to the superstructure.
We have added cross-beams and diagonal braces to the basic structure.  More diagonal braces to come. Note the plastic bags at the bottom of each upright.  This is vapor barrier stuff. Next is John's idea. To suppost the ridgepole use plywood. We have a big stash of outdoor plywood, kindly left behind by the previous owner of the house. Or someone. Here we are cutting a big triangle out of plywood. The big triangle will be notched to take the ridge beam, and the triangle (actually two of them) will be screwed on to the cross-beams. Plywood is amazing stuff. It will take enormous loads, because the plies in the plywood go at different angles to the grain. Nothing like free plywood.
Today John got the triangles up and the ridge beam placed. I neglected to take photos of this operation. But the ridge beam is up and running. Well, sitting, really. We very much do not want it to run. We want it to be still. The real purpose of the snow splitter, as I must have said before, is to keep the snow that slides off the roof from blocking out access to the house; save hours of shoveling hard compacted snow. This is impact loading. All the stuff you leaned in the strength of materials courses does not apply. It has to take a very sudden overload for about the one minute it takes the snow to slide off the roof. After that, the static load is trivial.

Anyway it is very pleasing. This is a much better structure than we put up last year, so we live and learn. I will add some more photos as this project progresses.

The birches have started to turn yellow. It is fall. More on that later. As usual our projects  progress JIT (Just In Time). Today it was 3C and that's warm. It got to 0.5C last Sunday. Close to freezing. 34F for metrically-impaired audiences. So it snowed in Fairbanks today. We have a very limited time to complete this project.

Thursday, September 12, 2013

You will remember our snow splitter. It collapsed under the onslaught of a thaw plus a lot of snow on the roof. If you don't remember, the relevant tag is "splitter."
So we are rebuilding the splitter. This time we used batter boards.
 A batter board is a simple framework upon which strings are set up. You adjust the strings so as to have equal diagonals. It is much easier to adjust strings than to adjust big heavy posts. You try to keep the string square, but the ultimate test is the diagonals. This is used both by constructors of big heavy structures and by cabinetmakers. If your diagonals are equal, the strucure is square, and that gets you out of a great many difficulties, because in construction you cannot rely on carpenter's squares, and the same is true for cabinetmakers. You should level the strings. I used a line level for the purpose. Then I sawed a notch in the batter board so that I wouldn't lose the reference.  Now you have corners for your framework. You dig holes at those corners.

Then (much later, like today) we set up the posts. Below, Fluffy holds up a post prior to leveling. John has rigged supports so we can plumb the posts.

 Once you have the batter boards (and the strings) it is relatively easy to set up the posts. Note that we have encased the posts in plastic bags. A bit of insurance against moisture seeping in.  We thank Fluffy's father for the advice. The posts are supported by temporary braces. Thanks, John.

And the rest is pouring concrete. So we did. A bag of concrete, high-early-strength (HES) stuff does the trick. One bag per upright post, but just in case we will add some more concrete. Lowe's is your friend. In the picture above Fluffy and John are recycling our concrete bags to provide a tent for our concrete, in case it rains tonight. It probably will. This is Alaska. Fall is rainy.  It has rained continually for the last week. This one day, it did not rain, and  we got a lot done. The posts are plumb . We will pour some more concrete as insurance, but this is a major step forward.