matthewkleinmannMore often than not my life feels like a "15 puzzle". For those of you who know know what they are, I just learned the proper name myself. They are those puzzles are sliding puzzles that consists of a frame of numbered square tiles in random order with one tile missing. The object of the puzzle is to place the tiles in order by making sliding moves that use the empty space.
This is a good analogy of life oftentimes. You want to do one thing but that one thing is dependent on the 14 things beneath it, and, and of course each of those has their own dependencies. On a really good day the dependencies don't overlap. You just need to get a lot of ducks lined up.
So, I have another project. I will no doubt write it up as it is interesting and I have a lt of faith that I can make it work. That project depends on making two wifi antenni. Wifi antenni are generally fun to make but not cost effective to make because you wind up getting taken for a ride on the pigtail you need to connect them to anything. That is unless you have a good junkbox.
Anyway, the antenni that I have in mind are a pair of Yagi's. These are a type of directional antenna invented in japan by a professor Shintaro Uda. One of his students filed the patent without professor Yahi's name on it, and now they are generally known as Yagi antennas.
I tend to be anal when I build things and I like making jigs, Truthfully it would probably be faster in this case to just crank out the two antennas in question by hand but that takes the fun out of it. Each one will be about 2 feet long and have 13 elements. The longest elements will be 56mm, so the entire antenna will be pretty small. I want to build the beam out of 3/4" PVC tubing and the elements out of 1mm stainless tig filler rod. The PVC will let me cap the end off weather tight with PVC caps and use PVC plumbing pieces to mount it.
I am envisioning three jigs. One is a hardwood V block that has a top cap that will hold a piece of 3/4" PVC tight in the groove with a bolt and wingnut at each end. The holes that the tig rod will go through will be drilled in the V block very accurately. Years ago I got an XY slide table for a drill press and I just remembered that I had it. It is just a bit too short to do all the holes in one pass but I suspect even with one re-zero part way through it will be much better than what I could do with a digital caliper or tape measure. The second jig will be a frame the PVC fits in with blocks on both sides to center all the elements. This one I will do with my digital caliper. And last, a block that you can bend the piece around to create the folded dipole driven element.
The idea being if I ever want to make another one of these, I can crank it out very quickly and with almost no measuring, except the elements themselves. I will cut them with a stop on my metal chop saw. As an aside, that was a recent purchase and I am wondering how I lived this many years without one.
So, the other night it is above freezing out. The shop is not heated. I figure I will go out and get the XY table set up on the drill press and get an idea of how all the pieces are going to fit together. I went to turn my drillress on and the lights dimmed and it barely turned. After a lot of looking at it, sand wasps had infested the motor. The entire motor was full of sand and the remains of their nests. The centripetal switch that controls the start capacitor (in a motor with one you can hear it click as the motor comes up to speed and no longer needs the start cap) and the bearings were the casualties. I was not happy.
It has also been decades since I bought a motor. I was unpleasantly surprised by what they cost, even at discount places like HF. Replacing the drill press was starting to sound like a more economical option, but this is a solid old beast and I am kind of attached to it.
Once in a while I get lucky though. In this case someone on the local freecycle posted, not with a motor, that would be like manna falling from the sky, but looking for wood shavings and sawdust. I told her I have a pile of each out in the shop and I have a truckload out next to my mill, but that is presently under a foot of snow.. Anyway, she was interested in the stuff in the shop and wanted an idea of how much. When I was out there checking on that I discovered that on the shelf under my lathe I had an extra motor I had totally forgot about.
I dusted it off and spun it over by hand and it turned smoothly. I fired it up and a bunch of black crap came out but it spun fine. I think I have my motor.
Another day! I was able to get the old motor off the drill press today. That turned out to be easier than I had hoped and feared. The old motor was held in place with carriage bolts and nuts. The square part of the carriage bolt fit in the slot on the back of the press and the nut along with a couple of washers were on the motor side. It was too close quarters to get a socket in there to take the nuts off from the motor side. As per usual, the correct fixed wrench size was MIA in the set at hand, but I was pleasantly surprised that I was able to get in there with a crescent wrench and once the nuts were broken free they came out the rest of the way with just my fingers. For a minute I thought I may have to go into my mechanical shop and find my gear wrenches,
The next step, getting the pulley set off turned out to be amazingly easy. A couple turns with an allen wrench and a little tap with a mallet just to break the corrosion seal and it slid right off. Things were just going too easy!
The new motor had a single pulley on it. That turned out to be a bit more of a challenge to get off. The set screw loosened up easily and after a couple taps with a mallet I was able to move it about a quarter of an inch with just my thumbs. I lubed it up good and slid it back and forth a few times. With my thumbs, I could get it to near the end of the shaft but not past that. This pulley had a key in it and it looked like the end of the key stuck up a wee bit. I tried a little tapping with my mallot, but that is banging right on the bearings and I prefer not to do that more than a little bit I went around with a steel brush and sandpaper and got rid of any burrs and all the corrosion on the shaft, but still the pulley stuck right at the end of the shaft. Urg.
The next step was looking around for my 3 jaw pullers. This pulley looked to be pretty sturdy steel, I really did not want to deform it, but I really did not want to stress the bearings in the motor. The 3 jaw puller pulls against the shaft so it has no effect on the bearings. That wound up doing the trick. A few turns on the pullers shaft once I got it lined up and finger tight and it popped right off. A bit of mallot action and a punch got the key out of the shaft. Some wire brushing and the shaft and key look like new. Yahoo!
The run of good luck had to come to an end though. The good news is the shaft on the new motor is not too big for the pulley tree. The bad news is it is too small. The other motor has what appears to be a homemade collar to adapt the shaft diameter. That appears to be seized onto the old motors shaft. I would also prefer a solution that is keyed so I am going to have to find my digital calipers and draw up a picture and see if I can find a friend with a metal lathe.
For cleanup I did mount the new motor on the press so I know that it fits, and it looks like there is a lot of adjustment in both the mounting slots for the motor, and the height that both the pulley trees mount on the shaft. I don't see any problems with the new motor except the shaft diameter.
For fun I fired up the old motor and all kinds of clay and mud fragments came out of it. Oddly I did here the centripetal switch click and the bearings don't feel as bad as I though they did. Then again the motor was under no load at all. Last time I tried it on the press it barely turned and dimmed the lights and the cord got hot. Yea, she was pulling a lot of current.