Ividing head saga, part 3

In our last episode we had gotten rid of the plastic stuff. Now it is time to do something more substantial.The first thing to do is to bolt a piece of steel onto the angle iron. You have seen another view of this before. There is a plastic spacer between the gear and the shaft. Now we have to make an upright to support the worm gear. There it is at the bottom of the picture..

But wait. The gear will not clear the shaft. So we have to mill out a 4mm pocket for the shaft. In steel and with a tiny mill (Cecil) this is an ordeal -- the biggest end mill is 3 mm and the pocket is maybe 30 mm. wide at the bottom. But the shape does not matter in the least, and there is less milling if you make it approximately circular. So there it is cut out. Now we have to attach it to the angle iron.

So to do this I had to drill and tap two holes in the angle iron. Thing about small stuff like this is that it vibrates like a reed, and bends over with drill pressure. So you have to support it. I used one of my micromachinist's jacks.

I made these machinist's jacks some time ago. I have two of them, and they are indispensable. A useful project for an apprentice. The paper underneath keeps the jack from slipping. Once you have the holes drilled, tapping is simple. Now we spot in the holes for bolts and screw in the worm support shaft. Voila (or is that voici?):

Now I have to drill a hole at an angle for the worm shaft. The angle has to be quite exact. Too shallow, the worm will miss the gear. Too deep, it will jam. So I am thinking about this one now. Yes, I know. If I had designed it in CAD all would be easy. But just as in music, some people can only play by the notes and others can improvise. Just look at Johann Sebastian Bach. In his day, he was famed as an improviser, and people came from afar to hear him play. Nowadays, everyone plays him by the notes. I think there is a moral there. I am slowly learning CAD, but after decades doing software, I am enjoying improvisation. And there is only one critical thing in the whole project: worm and gear. That is already done for me by the kind CNC people who designed the printer or whatever gadget I salvaged it from.

Dividing head, part 2

In the last post we saw the dividing head in its proto form. As near as I could reconstruct it, that is. But it is very flimsy, even though I intend to use it to cut clock wheels (gears) in plastic. So it is time for an upgrade to stiffer stuff.

The first step was to substitute the flimsy plastic for something a little more solid, like angle iron.

As you can see I have some angle iron -- actually, a piece off an old bedstead I found cast off long ago. I milled the outside as best I could, and I say that because it vibrates llike a tuning fork. I should have used a machininist's jack to damp out the vibes, but I forgot I had made one. The inside of the angle iron has a bar clamped to it. This allowed me to mark out and drill holes for screws to secure the bar to the angle iron. The result is the new improved mockup.

Now we have to put up a vertical bar to hold up the worm. I have that bar milled out, but you will have to wait, because this is the original Topsy. She just growed.
Of course, angle iron is neither square nor uniform, even though I milled the outside edges. It was very clear the worm-holding bar was way off vertical, a whole millimiter. So I spent some time milling out the place where the new bar will go.

 

 

This was quite successful. I had to take off a full millimeter to get it flat.
Next step: square up the bar without moving anything. Then we will worry about the base, and if push comes to shove we will use shims to level it.

In retrospect, if  I had a casting why that would be the way to go. But I have no casting facilities. But so far this has been very enjoyable. Stay, as they say, tuned.

Genesis of a Dividing Head

One of the oldest problems in the world is dividing a circle into equal parts, like cutting a pie into exactly equal parts. We face this problem every time we cut a cake or pie -- how do we give everyone equal portions?  Well, I am trying to build a clock. The Isaacs clock, published long ago in Model Engineer magazine.A beginner's clock, to be sure. To do that I have to build gears. To do that I have to divide a circle into equal parts, corresponding to the number of teeth on the gear. I have a series in this blog (label "divider") on how I did it on the Taig. I built divider plates. Trouble  is, one of the gears on the Isaacs clock has 100-plus teeth. The radius required for a divider plate with that many holes in it is much too big to swing on the tiny Taig. I have learned since that there is a way around that, thanks to Tom Lipton. But at the time I hadn't watched his video.

So while I was still at Chalupy, and half my stuff was packed up, I had an idea. Every time I find a discarded printer, I take it apart. It is a treasure trove of supplies. Ground rod, plastic gears, racks, pinions, motors, name it. So I found a worm and gear of the same module (n.b. for techies, module is the reciprocal of diametral pitch, but expressed in millimeters). So I set out to build myself a dividing head. -- a gadget that will solve the cake-cutting problem very exactly.

This is a project I am making up as I go along. I regret that I seem to have lost the pictures I took at the time. I will attempt to reconstruct the process.

Above are the basic ingredients. The screwlike thing in the middle is called a worm. It is in fact a screw, rather coarse-pitch. It is on a shaft and bearing. The shaft is a piece of brass welding rod, about 3mm diameter.  Bearing is simply a square bar with a hole in the middle. Below is the gear. It happens to have 72 teeth. The gear will be pressed on to the shaft. The right end of the shaft is turned smooth. The left end is my best attempt to duplicate the Proxxon (Cecil B. de Mill) spindle, complete with collet closer. A major turning project which I did here in Anchorage. Then I can use Proxxon collets to hold the proto-gear that I wish to cut.
Now let us assemble the thing. I will cut gears  on Cecil. I have much more precise control on the speeds and movements of the mill table.

This is a real lashup which I will remedy. I hope. The clear plastic is a frame. You see the worm meshing with the gear. Now, an interesting property of worm-and-gear is thatevery time the worm turns exactly one revolution the gear advances one tooth. If we had to cut a 72-tooth gear, we would turn the shaft one turn, cut, turn one more rev, cut ... rinse and repeat. But if we wanted fewer teeth then we would have to turn more than one rev; if we want more teeth we have to turn less than one rev. We do this by using dividing plates. I have also made these things, but that will have to wait for another episode.

A commerical dividing head is quite expensive,and much bigger than my entire mill. No hope there. Proxxon builds a rotary table but very expensive. So stay tuned. This may or may not work!

A pipe tool and a pantograph

A strange mixture of topics. But bear with me. I got so exicted about using the graver on the Taig that I decided to make something useful on it. The result is a pipe tool. This is the thing us pipe smokers use to tamp down the pipe, clean out the bore, and scrape out the pipe bowl.

The handle was turned on the Taig out of Aluminum. Freehand, with the graver. I am not yet in the brass-turning league, I am working my way up to it. The wire stem cleaner is "music wire" from Lowe's. It says "easily bent for school projects." Hah! Easily bent  by Superman, yes. I had to anneal it to forge the loop. The blade is an ex-hacksaw blade ground to shape and moderately sharpened. There is a slot milled in it, and a brass rivet to hold it all together. It works like a charm. Note the taper at the end of the handle; all by hand. It acts as the tamper. Altogether an extension of the Taig lathe.

The above pic will give you and idea of scale.

So the next thing for this week is that I got all exited about Stefan Gottteswinter's YouTube channel (q.g.) because he has a marvellous precision engraving machine. It is based on the pantograph principle. So what is a panotgraph? It is a device that allows you to reduce, or expand,  a basic pattern in a given ratio. If you are trying to make something very small, it is an advantage to make it twice (or more) times larger and then reduce it via pantograph. So what is a pantograph?

A simple paralleogram. The corners can all pivot. Across the bottom bar are a row of holes,   into which I stick a Sharpie. The midpoint gives me a 2:1 redusction. 1/3 of the way across gives me 3:1. To the right of the midpoint, I get magnification. Not too interested in that.

This is a crude mockup. I am using Sharpies in the holes and tracing the image of a crude letter O on the paper; I did the O freehand. The pin next to the big wood O is the tracer end. The whole thing is a flimsy contraption, built in a few hours, but I got the principle of the thing down with it.

Next thing to do is to rebuild this thing out of metal and adapt it to take a Dremel tool. Then I can do some serious stuff. Stay tuned.

The grave(r) state of affairs

So this afternoon I decided to play on the Taig lathe. I have been doing a project, which I will describe later. It requires great precision and careful measuring. Well, I was kind of tired of the .01 mm stuff. Wanted something  more freehand. I have been reading my clockmacking/watchmaking books. They do not always employ toolpost-held tools. Instead they use hand-held tools called gravers. These are not unlike wood-turning tools on a wood lathe. But the idea is the same. You use the graver much like you would use a skew chisel in wood turning. The book said "it is not mysterious. Take a piece of faced-off brass and round the corners. That will get you started". OK, let's try it.

Using Handy Bandy I sawed off a piece of aluminum rod. I did not dare to use brass because it is expensive and not easy to obtain. About 20 minutes later...

... I had the shape  you see above. The end looks rather like a ball and the other decoration is sort of an ellipsoid. All freehand. Whee! This is fun! Notice I was using the chuck. Not a good idea, because the tool can hit the chuck. So what is a graver?

A graver is nothing more than a chisel. I had this tool, which you see above. I had made it to cut threads on the pole lathe by chasing. I reground it. With it, I faced off (squared) the end of the bandsaw cut -- freehand. It takes quite some practice to learn how to use a graver. There are three axes (pitch, roll, yaw) and you have to get all three right. Note I am using the standard Taig wood-turning tool rest.

After a while I learned my wood-turning parting tool works just as well for cutting grooves in Aluminum as it does on wood. Not surprising, Steel much harder than Ally. So I learned to rough out with the parting tool and blend in with the graver.

Much more to learn. For instance, the chuck is a bad idea. It interferes with tool movement. So fortunately I have acquired a set of ER collets and an adapter to replace the Taig collets. This is a much better option than the chuck. More to come. Still learning, but it is very enjoyable.

The New Shop

On examining my camera --w hich has sat, batteries flat. for some time now -- I seem to have lost a whole bunch of photos. Well, such is life in these modern electronic times. So I will have to reconstruct a whole bunch of projected posts.

So while I do, I thought I would give you a tour through my new shop. I have one half of a two-car garage. This seems like a huge luxury. Much more space than I had before, namely one hallway. Let's start at the garage door.

My priceless woodworking bench, which I built in Juneau some years ago now, occupies pride of place. At last I can do woodworking in winter. Previously Mr Workbench lived in the barn -- very cold in winter.  Impossibly so. In the foreground, two out of my three trusty Workmates (TM) . Just wait until you see the vise I got for this workbench. Meantime it's Workmates for clamping. Moving om to the rear of the garage, we have the metalworking machine bench, exactly as it was at Chalupy. Lathe, mill, drill press. No novelty there. I had, of course to add some shelves.

The aassembly/general workbench follows towards the rear. Again, some wood to hold all the tools I need.
 

 Finally there is the grinder bench , -- the shinto temple of a previous post -- with my grinders and a new contraption, the cabinet. Madame Cabinet is a winter project. It is a ten-drawer cabinet which I hope will reduce the clutter in the shop. I built it out of a couple 1x2s, and some particle board. It deserves a post all to itself, maybe I'll do one.

With this environment in mind I will reconstruct the projects currently underway, as soon as I get a new memory card for the camera.

And now it's time for bed.

Chalupy Acres lives again!!

I have been stymied from posting by the internet situation in this new home. My "real" computer was set up for an ethernet connection at Chalupy. The box from the phone line went into the router. From there I ran an ethernet cable to the conputer, and presto! Internet.

Here I was limited to an evil laptop. At least it spoke wi-fi. Getting a USB mouse helped a lot. But I still didn't have all my familiar software. All the stuff to get photos off the camera, all the nice keyboard features that I have become used to. So my daughter had a brilliant idea. The cable company supplied a cable modem. Form thence we went to a router which supplied wi-fi to the whole house. But an ethernet cable from the router (upstairs) would have been about 30 meters long -- posssible but very unsightly. Or I could have drilled a hole in the floor -- verboten. Or I could put a wireless USB "dongle" on my real computer. Which I did, but there is something missing. "Device not found" it says.

The brilliant idea was to note that the downstairs room where I have my stuff set up has a cable outlet. So why not attach the cable modem to the downstairs connection, take the router downstairs, and plug ethernet into that? IT WORKED. The router broadcasts wi-fi everywhere, so why worry about the cable modem/router location?

So now I am online again downstairs. I now have to revive my camera and get the photos off it, and I might be in business again. Note the absence of pictures in this post. When I get the camera up I can show you what I have been doing. Several projects, the new shop, the whole thing. Cameras, unfortunately, require batteries and I am afraid that this may take a few days.  And I may have lost a few photos.

Chalupy acres apologizes for the long absence, but hope is in the air.