Harold and Susan Vordos wrote:
"DE" wrote in message
news snip---

I'm looking forward to winter and some extended chipmaking time.
I schooled on big industial iron 30 years ago, I must have had a good
instructor as everything has come back with litte reference to my
notes, We didn't have any dro's there, I was taught to use a dial
indicator for high tolerance positioning. I never have used a dro.

DE


DRO's are an incredible device, but my honest opinion is they cheat the user
out of a proper learning experience. Having been trained as a machinist
in the late 50's, no such devices were at our disposal. I learned how to
run machines by applying skill------skill that will always be with you, much
the same as hand grinding HSS tool bits. When you learn to machine using
such devices as insert carbide and positioning devices, you tend to short
circuit that portion of your learning, which often leads to a lack of
knowledge needed in other operations. It's something that has the
potential to haunt you endlessly.

Backlash is a non-issue. The only time it matters is if you climb mill, and
the machine is too loose, or when you don't understand how to work with it,
which one often doesn't when a DRO is used.

Having worked in the trade for years, I can say, with total honesty, what
scrap I've made isn't attributed to backlash---it's from making other stupid
mistakes.

I'm proud to say, I have NEVER used a DRO, and I've done a ton of work with
tolerance restricted to a thou in many instances. A good portion of my work
was building tools.

Did I mention all my work was subject to proper inspection by a an
independent source? I couldn't fake it.

Harold




There is likely a big difference between the machines you used and a
mill-drill, the subject of this thread. Mill drills don't have the mass,
scraped ways, or ball screws found in the bigger machines. An
experienced, skilled operator on a heavy, well-tuned BP can hold the
tolerances needed for precision tooling work. Operators with those
skills are hard to find these days as most are retired or dead. My
experience with mill-drills using the handle dials is a tolerance of +/-
..01 on a good day. Add a DRO and you can cut that error in half, maybe a
third with some practice.

When I set up our shop a couple of years ago, we skipped manual mills
altogether and installed VMCs. The old mill drill is still around, but
it's rarely used. On a VMC, anyone who can properly load the vise will
turn out parts with accuracy better than +/-.002, all day long.