[...]
Well. I made long, stringy chips and did some experimentation with
chip breaker grooves. Not much, though. A very light shallow groove
worked quite well for most of what I was doing, so I didn't bother going
any deeper. Once I have an better supply of tool steel I'll get a
little more adventurous with my grinding.
But a funny thing happened that'll let me try another strategy for
manufacturing my flywheel. Previously, I was considering simply
restarting the flywheel even though it would mean a hit to my grade.
And today some folks were in the shop filming students engaged in hot,
sweaty, unadulterated learning. At one point they asked me to swap
places with another guy since I was short and he was tall. OK, I leave
him with a simple command: don't move or cut anything; just look pretty.
Of course, since he was one of the guys who almost never shows up he
can't follow simple instructions; when I got back the hub was gone from
my wheel--he also took the whole 1/8" in a single pass. At 1500 RPM.
Cool! I get to restart it and try a better way of making it, I have
free reign to mock the annoying twit, and I'm on TV! But the downside
is that he savagely molested my carefully ground tool. (not the one I
described in the other post--this is another tool that was prescribed by
the teacher for this project. Looks like a grooving tool about 3/16"
wide) I ground the tool back about 1/8" to get the evil off then let the
teacher know I was starting over and it wasn't my fault.
To face the piece I found that going from front to back with my tool
(fancy one, with the rake angles and chip breaker stuff) didn't work too
well. Came out nasty and teary and looked like hell and got hot. But I
was smart (at least I thought I was smart) and rearranged my tooling.
Instead of the normal mounting, I had the tool parallel with the axis of
the lathe, ran the lathe backwards, and moved the cross feed from back
to front. So, from the bit's POV, it was moving from right to left
across the face of the part. Near-mirror finish and I could go a lot
faster. First time in this class I've turned something to size +/-0.000
and perfectly flat all across. Stayed cool, too. Yay!
Now I'm tempted to make the ass-end of that toolbit for left-to-right
cutting so I can use a similar setup without having to run the lathe
backwards--just in case I'm stuck with one that can't.
So far for the wheel I've faced my piece to length and drilled and
reamed a hole. Before the end of class I got part way through making a
mandrel to hold it. It was a piece of scrap someone else left that was
a disc with a tit poking out of the center on one side. I faced the
wheel flat and turned that tit to my final size + about 0.030" so I'll
be able to center it up next class. I still plan to drill, tap and
split the tit for an expander screw. If I wind up having to remove the
holder before I finish we have a four-jaw chuck on one lathe, so I can
recenter it. I probably need to learn how to do that anyway.
This is getting to be scarily fun--I was actually happy when I found
out I had to do the wheel again. Damnit, I wish I could fit a lathe in
my apartment.
--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/