Steady Rest, some more

I have been away in Anchorage for the last two weeks. Although I can post from there, the laptop I use drives me to distraction. Most of this is caused by the touchpad cursor; I suppose I could do something about that -- but the laptop also runs Ubuntu Linux, which I hate. Just me. I could fix all these things, but I don't feel it's worth the effort.

While I was in Anch I did some carving, a pleasant change from machine work. That's a future post. I would like to record progress on my steady rest.  All of it before I left for Anchorage.

I finished milling the dovetail slides and for improvised cutting setup it was a very good fit. I was pleased. I will have to drill and tap some holes for fixing screws, but that comes later.



 Next picture: the body of the steady. It will be screwed to the dovetailed piece.This is just drill and tap. I will not show it.

Now comes the really crucial step. I must put a great big hole (25mm) in the vertical plate. The center of the hole must be exactly at center height on the lathe. Once  you get the hole drilled, the center is gone! So I put a sharp point in the lathe chuck, and located the centerpoint by tapping the work with a hammer. That is center height. (The nominal height is 2.5" or about 62mm, but it is not advisable to rely on this.). we have a centerpunch mark. Right where it belongs.

So we can drill a pilot hole on the punch mark.  Now if I could chuck this in the lathe I'd be in clover. I could bore it out with a boring bar. But the upright will not "swing" in the lathe. Obviously -- it is at center height. So we will have to mill it out. The big boys do this on a rotary table. I have no such animal. It costs almost as much as the mill! So instead I built a fixture.

 Somewhere on my walks I found a very heavy piece of steel; whence it comes I know not. But I drilled my work something like 6mm and also my fixture, more or less in the middle. I pushed the work on to the pin. Then I could rotate the work around the pin, with my hand. So the cutter cuts a circle. Keep increasing the Z axis till you go through. This is definitely the pauper's rotary table! But it works. As Tom Lipton says, "we're all heroes in Aluminum".

After this, all that remains is to screw the upright back on, drill and tap the fixing screws, and make the fingers. 

Bought some aluminum to make the fingers. Haven't done a thing yet; busy carving. At least next post will be a relief from all this machining.We'll be doing some carving in wood for a change.

Milling around

 Looking at my labels I am surprised I don't have a label for "milling." But I do have a label for "Proxxon mill". The only mill I have, in fact. A mill holds the work still, and a cutter revolves. In a lathe it is the other way around. Both are very useful in my miniature machine shop. I have been milling (and turning) for quite a few days now, in fact is quite an obsession. My first attempts at milling have been documented. But now I want to cut flutes on the clamp bolts on my digital indicator stand.Ideally, in machinespeak, these would be knurled on the lathe. But I don't have a knurling wheel set.

 
 Instead, I took a  hint from Tom Lipton's oxtool videos and cut flutes instead. Very nice. I decided to use 8 flutes. This required making the fixture shown above. A square piece of aluminum. I scribed one line at 45 deg. By simply flipping the fixture around I can cut four flutes. Then I carefully align any one of the flutes I just cut. And I then, by flipping, cut four more flutes. My steampunk dial indicator stand is really beautiful now. And I can adjust it with my fingers. Should have a pic of it, but omitted to get one.

However, today I decided to make a fly cutter for the mill. I had a piece of very nice steel, taken from a defunct printer. It made the clamp bolts. Now I want to make a fly cutter out of the rest of it. A fly cutter is used to level out rough surfaces. I did some internet research. There is always myfordboy to the rescue. Another good reference is Dean. From these two references, I extracted the fact that a fly cutter must be angled to the work. I picked 45 deg per myfordboy. OK, I have this piece of 13mm (more or less) round bar, and I have to drill a 45 deg hole in it. How do I do this? I spent the entire morning working this out. I am no professional machinist! I finally cobbled up the setup shown below.

  
I held the round in the vise.  It is pure serendipity that the Taig milling vise (Imperial) fits the Proxxon mill (metric).  I propped it the round bar on a step block kindly provided by Proxxon. Thanks Proxxon! I packed things up with stray aluminum scrap and it all worked, a miracle because the mill is metric and the rest of it is all Imperial. But Aluminum has a bit of squish in it, so the thing was well held.

Next problem is to drill the hole. Were you to simply bear down with the drill, it would skitter all over the place. This is not wood, it is metal. So I had previously made a 2mm or so end mill out of a broken drill. Ground it to shape. I ran this end mill so it made a little step in the round bar. The step gives the drill something to bite into. So I went through with a small drill and then a 3.2 mm drill (0.125") which is a collet size I have -- standard Dremel size shank. I had very carefully drawn out the thing to scale, a very good idea.

Next step was to turn down the shank to something that would fit a 3.2 mm collet. Straightforward turning. Now I have to make a setsrew hole in the thing to hold the cutter bit. Not to mention grind the cutter bit itself! That's another day's post.

Now I have to figure out how to get a setscrew in there to hold the cutter bit down. Later.

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.