"Bill Schwab" wrote in message
nk.net...
Harold,
snip---
It took a few minutes, but after several readings, I think we describing
the same thing.
Most likely so. You appear to have a firm grasp of what's being discussed.
A machine with
worn screws and nuts is still capable of doing decent work, so long as
you
don't rely on them to locate over large areas.
My machine should be nowhere close to having such problems.
Assuming the screw was accurately made, I'd agree.
However, it
does perhaps suggest that I might want to be a little more agressive
with the way oil in a few places.
You can't oil too much, not on such machines. It's messy, but it preserves
their useful life. The best policy is for oil to never be black---if it
is----it's showing signs of wear of the machine. I keep my ways wiped
and oiled such that the Vactra used always looks like Vactra, never black.
I also oil the screws on my machines when used, and will often stop during
the course of the day and re-oil. It's the cheapest of all insurances.
Think Oil-Dri (kitty litter).
Another suggestion I found interesting is to use a plunge indicator,
though that has obvious range limits.
That is the one cheat I permit myself, especially when running a lathe. It
takes all the guess work out of linear dimensions, and is particularly
useful if you follow up with second and third cuts. O ring or snap ring
grooves, for example. Parting a piece after machining is another. My
setups when making anything in quantity are much like one a person would
make running a CNC---but it's all done manually. Care must be observed
in setting up a long travel indicator that it is parallel to the carriage or
table travel so you get an accurate reading.
Keep a 6" scale at your disposal (larger, if necessary) and
use it routinely.
I'm already doing pretty much that, and it has already saved me time and
materials. The hard part has been getting the scale. I have been
(ab)using my dial caliper for the same job, and look forward to placing
my next order (which will include the scale) so it can get a break.
Good idea. A scale will generally get in where other things won't, and
it's much easier to keep near. I have mine in my shirt pocket always.
With the heavy trend toward SUVs and other large vehicles, the public
didn't appear too worried about fuel consumption, and I suspect the auto
makers got lazy as a result. Is there a difference in performance?
Lets see----we're discussing my 3/4 ton '94 Dodge with Cummins engine, as
compared to my '99 Dodge, Cummins engine, and mileage.
The '99 has double valves and likely other "improvements" as compared to the
'94. As far as I know, the engines are the same size----------but it's hard
to compare them due to some variables. The '94 is a 2 x 4, standard bed,
and automatic. The '99 I bought new as a cab & chassis, long wheelbase, on
which I had a 10' enclosed box (a delivery van type box) installed. It's an
all wheel drive vehicle, and weighs considerably more than the '94. It's
a 5 speed manual. Gear ratios are the same, as are tire sizes. The
difference in mileage showed up even before the box was added. I had driven
it about 300 miles before delivering it for the box to be installed. The
differences in mileage don't appear to be based on better performance,
although, as I said, it's difficult to compare the two vehicles. I like
both of them quite well, but would like better mileage from the '99. I'm
tickled with the '94. Who else do you know that gets over 20 MPG with a 3/4
ton full sized truck? the '86 GMC I sold gave us just over 10, with a stiff
tail wind.
So you are leaving some metal and later correcting. Do you then simply
assume that a 0.5 in endmill has a radius of 0.25 in and leave the final
cut(s) to clean up the error?
No! I never assume the diameter of an end mill. It's too easy to measure
them, and the same thing goes for twist drills. When I run my mill and the
cutter size is of concern, I usually find one that is best suited to the job
at hand, measure it, then allow for the diameter. If you get in the habit
of trusting nominal sizes and you have your end mills sharpened, you'll
eventually get in trouble unless you know the size in use. Keep in mind
I'm speaking from the perspective of the guy that might be machining for
gain, working to tight tolerances, secure in the knowledge that the work
will be inspected. For the home shop guy that is making something that's
not critical, it may not matter. Still, you're building work habits when
you run the machines, so it's always a good idea to pursue perfection.
Makes it easier when there's a demand. I've worked with more than my
share of guys that had a "that's good enough" attitude, and couldn't handle
tight tolerance work when it was necessary.
it successfully----but it's not hard to do. No, you don't get a
step----the
cut is seamless.
Nice! I probably couldn't do it right now to save my life, but I see
what you are doing.
Try it each time you cut a pocket or window. I've never come up with a
better way, and it's almost as easy as doing nothing but coming into the
corner, which almost always leaves a tell-tale mark, or undercut.
Don't say lathe right now - my evil twin (the one who buys all of the
machines) might be reading over my shoulder 
Chuckle! Just keep thinking Monarch EE! :-)
Thanks!
Bill
Again, *Welcome*
Harold