[Coco] [coco] Coco CNC

[Gene Heskett]

On Wednesday 13 February 2008, George Ramsower wrote:
>I have that lead screw nut fitted to the slide now..
>
>http://coco.thetinbox.com/NewMillPageTwo.html
>
>It's fun to watch this thing work, especially knowing a Coco is operating
>it. So far accuracy on the Z axis is dead on and side milling is within .003
>inches. Not too bad for a dremmel.
>
Looking good George.  Are you going to need to deepen the other end of the 
groove too, to clear the screw as it protrudes from the nut?

I am getting closer to having the 4th axis working on my mill, a motorized 4" 
rotary table.  For a drive coupling, I re-used the coupling I originally made 
for the first rebuild of the z axis, but had to bore half of it out to 10mm 
from 8mm, which turned out to be fun.  I'd made those originally out of some 
sort of worn out mine shafting I'd found at the scrap metals place & bought a 
few feet of, and had fun making in them in the first place cuz it was such 
hard steel.  I pretty well wrecked a drill bit that was about 9.5mm but it 
did go thru, but when I hit it with a small carbide tipped boring bar to 
finish up the fit, the bar just slid off, so I wound up making a strap bolted 
to one of my quick change tool holders with a tab sticking out with a 1/2" 
hole in it, put the hand piece of a flexible cable for a Dremel through the 
hole, and mounted a 1/8" diameter diamond coated ball burr from one of those 
ten dollar kits, and made about 20 passes through it to center up the hole 
and enlarge it to fit the 10mm shaft.  Dremel set for about 5 thou, lathe at 
50 rpm with its slowest gear feed.  Very very slow, but it worked.

The last time I dealt with steel this hard was when drilling and tapping my 
P17 Eddystone Enfield action for a scope 45 years ago, where we had to spot 
the top of it with a grinder before a carbide tap drill for 6-48 screws could 
touch it, and the carbide tap had to be sharpened about every turn.  I still 
have whats left of both of them!

Then I had to take Dee bowling as the weather was threatening so progress 
stopped as I needed a nap when we got back.  Maybe after dinner I'll get back 
to it.  Next is pulling the existing z motor and installing one of the 430's 
in its place, and then using the 262 I take off for this.  But I'll test it 
with one of the 430's on it first.  Then I need to source some of those 4 pin 
screw together mic connectors they use on CB radios.  Everything is connected 
with molex's ATM, and the back of those is open so swarf could get in and 
short them out.  I've been lucky so far but sure as heck I get complacent, 
I'll wind up letting the smoke out of the driver board.

Its amazing what serves for entertainment as we make this long journey called 
life...  Its been quite a ride so far. :-) 

-- 
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)
Why are these athletic shoe salesmen following me??