Ford Chevy , Coors Bud ..... My new to me Enco 11x20 has 2 scales
on each hand wheel for the cross & compound slide . I'm not
setup with yet so I don't know what each dial means? yet .
I think for most hobbyist's the functions on a dro on? a lathe
don't get looked at much furthur than the travel function . On a
mill there's a few more that most folks would use besides just the
travel? Like the bolt circle for one .
animal
On 12/22/23 7:45 AM, Charles Kinzer
wrote:
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Actually, there are three
countries still using the Imperial system:? The U.S., and also
the industrial powerhouses of Myanmar and Liberia (both of
whom are actively converting to metric).
Regarding the inch marked
metric threaded (1 mm per handwheel turn) 39.4 thousandths
masquerading as 40 thousandths.? This makes each handwheel
turn come up 0.0006 thousandths short...OK, so that's about a
"half tenth" which is usually trivial in the mini lathe world,
but multiple turns have a cumulative error.
It always surprised me that
more people didn't complain about that with their mini
lathes.? But I got responses that people make final cuts to a
measurement anyway and it didn't bother them.? And maybe if
only working on smaller parts, they were depending on many, or
any, full turns of the hand wheel to final cut.
At least one mini lathe I saw
long aga at least had the handwheels honestly marked.? Instead
of 40 even divisions, it had 39 that DID represent one
thousandth each and then smaller division just before you
reached zero again to cover the 0.4 thousandths.
On a mini-mill, I think it is
much more of a liability.? You are often doing a lot of table
travel (often by counting a fairly large number of turns) and
that error per turn will add up to something often
unacceptable.
When I bought a Chinese
mini-lathe and mini-mill many years ago just for fun (and
ended up using them far more than I expected as I have larger
machines) I got the Micro-Mark "True Inch" variety.? It seems
Micro-Mark has some exclusive agreement with Sieg (who
manufactures them) so that nobody else can sell them.
I recall that Little Machine
Shop at one time sold conversion kits to make your lathe or
mill have truly inch based travel screws with new handwheels.?
I don't know if they sell that anymore.? I looked a little and
couldn't find it.
For DRO's, I believe the
answer to that, and almost any such question, is that there is
no answer.? It depends on the person's needs or perhaps merely
desires or available funds or even their eyesight.
Charles E. "Chuck" Kinzer
On Friday, December 22, 2023 at 07:01:06 AM PST,
Miket_NYC
<mctaglieri@...> wrote:
DROs aren't worth the money and trouble to me. I
use a dial indicator with a magnetic back on my
mini-lathe, my my 11" Logan lathe, and the Z axis of
my mini-mill. Not as pretty or cool-looking as a DRO,
but I can move it around as needed.
For the mini-mill's X travel, I have a 2" travel
dial indicator (The calibration for the X travel of
the Imperial mini-mill is ridiculous. It has a
16-tpi leadscrew, which requires a fractional number
of thousandths on the dial. The factory in China
maybe figured Americans were too stupid to notice,
and since we're the only country that still uses the
Imperial system, maybe we are. I wish I had bought a
metric mini-mill.
Finally, I like the 2" travel indicator on the
mini-mill so much that I now wish the magnetic dial
indicator I move around on the lathes and the mill
was also 2", but?it's just 1". Maybe 2023 is time to
change that.?
Mike Taglieri?
A DRO is much more useful on a mill
than on a lathe. ? What makes them great compared
to the numbers on the hand wheel is that the DRO
has no backlash.? It shows the real location of
the axis.? The other good feature they all have is
a zero-reset.? If you need to move (say) 10 mm
from current location, then set to zero and ?turn
the handle until the DRO read ¡°10.00¡±. ?
I used screws to mount them but as it turns
out tonight I¡¯m ordering some powerful magnets
for another project and I¡¯m thinking how easy it
would be to use CA glue to put the magnet on the
DRO and magnetically mount the DRO.
[Edited Message Follows]
When DRO is working they great.
I had a set on a Bridgeport for 20 years.
They work great but the rest mills I had
did not have DRO'S and still used them
without any problems.?
When work as a Journeyman Machinist I
would go into shop and DRO's work haft the
time as you use the tool.
I finely got set I move from tool to tool
if need.?
They are wonderful if treat with care.
Dave
FYI?
I have a set of Shars in my tool box since
2009.
