[Coco] [coco] Coco CNC

[Gene Heskett]

On Saturday 16 February 2008, George Ramsower wrote:
>----- Original Message -----
[...]

> The stairstep wasn't the dremmel... dammit! I was MY bad. I missed by about
>.023 on the Y slide and it was not aligned perpendicular to the table. Also,
>the Z slide was off a tad also. I got that done today, faced that throw away
>part again and it is beautiful. Now I can face the working table and get it
>flat.

Great! (In my best Tony the Tiger voice)

> The working table was saw cut from a much larger piece that was extruded.
>So it was not perfect. However, I used this imperfection to enable the
>clamping of the X axis nut. Had to really tighten the mounting screws to the
>X slide to pull it down almost flat. It was slightly curved. All this turned
>out really well as now I have a very solid working table to work from.
> Tonight, I will begin the surfacing of that table to ensure it's flat.
>
>> I put some more links to pix up on my web page.  Gotta make up some
>> explanatory text one of these days to wrap around the pix.  Its not
>> running
>> yet, waiting on a couple of bags of enclosed connectors, I'm going to
>> switch
>> the whole lashup away from those molex's before I get a piece of swarf in
>> them and short out the driver board.  Tain't purty, or cheap, did that
>> once. :(
>
> You call it swarf. We call it chips. I suppose if it's wood, it's swarf. I
>have never gotten "swarf " in my foot. Chips penetrate quite well and are
>difficult to get out.
>
Chuckle, wood chips are sawdust, steel chips are swarf.  And because it tracks 
in on my shoes, I had to take my pocket knife and excavate a  teeny bit of 
swarf from one of the wifes toes today. The tip of my knife is VERY sharp, 
and works much neater than trying to dig it out with the usual ball point 
sewing needle.

>> The Ampmeter says its 15 volt, but it is actually 1.5 amps full scale, and
>> is
>> currently clipped into the ac fuse circuit so I can see how hard the
>> spindle
>> is working.  It gets wired in solid, and solidly mounted beside the
>> spindle
>> motor one of these days (or nights as the case may be)
>
> I've used voltmeters to measure amps, with the appropriate shunt. All we
>have to do is KNOW it's amps and not volts.
> I've also used an oscilloscope as an ammeter. All that's needed is a shunt
>resistor.

So have I.

In this case I'm actually measuring voltage, its a full wave bridge in series 
with the fuse, its output is shorted more or less by a 1 ohm 10 watt 
resistor, and a 1.5k buildout resistor drives the 85 ohm, 1ma meter that 
thing actually is.

[...]
>> too,
>> but if I turn it on full time, battery life is 10 minutes max.
>
> Parallax is a bitch. This is one reason I love my view camera.

My last view camera was over 55 years ago, and I couldn't afford to keep it in 
super x film then or now.  An old 5x7 Anniversary speed graphic, but the 
window shade was pretty well shot.  I had some sort of an Ansco 4 element 
F4.5 190 mm on it, and no front shutter.

[...]

>view camera with regular silver halide film. They are approaching the
>quality of 35mm now with the 11 meg stuff... not ain't quite there, yet.

Yeah, for this I should really go back to my SLR, I have lenses from 28mm to 
300mm, and as fast as F1.4 for it.  I had to hit the pawn shops about 10 
years ago & find another Pentax threaded body (a Vivitar believe it or not) 
with that same great Copal Square shutter in it, mine was beginning to leak 
at times.  A Richoh TLS body, it probably has seen over 20 miles of film it 
its day cuz I've usually had my own color darkroom rigged up no matter where 
I was hanging my pants at night.

But even at 11 megs of pixels, the digitals still can't touch, don't even 
belong in the same room, as my 85mm F2.5 Ashahi lens putting its image onto a 
frame of high contrast copy exposed as if it was ASA 10 film & developed in 
homemade D22.  There you can print 16x20's of a subject 10 feet from the 
lens, and still count every hair on their head in the print.  Digital's don't 
even have dreams of doing work that sharp.

That old Olympus is only a 3.2 megapixel, I'll think about a new one when it 
dies, or they hit 20 megapixels at <$300, maybe another 2 years.

>> Figuratively speaking, I think George is actually making progress faster
>> than
>> I am.  He already knows the basics of the machinery, something I'm
>> learning
>> as I go.
>
> Yeah, basics is about it. Only eight months in a real machine shop doesn't
>really count for much, but it was a learning experience. However, I've been
>turning stuff on lathes for many years and learning my manual milling
>machine for about ten years. I couldn't tell you how many parts I've tossed
>because I didn't do it correctly.

I have a corner in the shop for those, I might need a smaller gismo I can make 
out of an old mistake. Wood scraps go there too, potential glue blocks etc 
doncha know. :-)

> You are learning tooling, setup, fixturing and programming all at the same
>time. That's a lot to do. All I have to do is learn tooling, setup,
>fixturing, and programming on my Coco CNC machine.
>
> DOH! It's the same!  And I still haven't made a part, yet. You have! So
>maybe you are ahead of me!

Maybe, but I haven't made the machine from scratch either, just trying to fix 
its biggest faults.  That back of the post z axis drive is a major design 
flaw of that toy mill, the gibs bind so bad you cannot put 5 lbs of push on a 
drill bit so you must position the bit, then drill with the handle on the 
head, which I normally keep clamped up tight to reduce chatter.  Now I can 
drive a 1/4" bit hard enough by pushing the 'page down' button on the 
keyboard that I can go the first half inch deep in that alu I'm carving in 
about 15 seconds with a pair of continuous strings coming back up the drills 
flutes.  After that I have to back out and clean the bit at about 1/8" 
intervals, as usual on a drill press.  That alu is a bit 'soft and gummy', no 
idea what its numerical designation might be as I came by that block, 5" 
square and about 23" long, for a 40 dollar bill at the scrap metals place.  
7078-T6 it ain't.  I love working that -T6 stuff, the bits don't but I do.  I 
have about 10" of it left now, so I'll have to find another hunk eventually.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Keep your laws off my body!