On 2012-03-07, Grumpy wrote:
Does anybody here have any experience with the Eason ES-8 DRO?
We have one on a lathe in the museum workshop where I volunteer restoring
old machinery such as steam traction engines and similar stuff. We have a
relatively new(18 months) lathe with the Eason DRO on it. I'm having a bit
of trouble with it and, as I'm not to familiar with DRO's, don't know
whether I'm expecting too much from it or if there is something wrong with
it. I take an initial cut with the lathe, then measure the diameter of the
work and set it into the DRO and hit enter. I then put the next cut and turn
on the motor. The reading immediately changes and dances around by a few
hundreds of a millemeter or thou. After taking the cut on the work, I
measure it and find that it is off by as much as 7 hundredths of a
millimeter from what the DRO says it should be.

Looks to be spelled Easson (two 's's) according to a Google
search.

Hmm ... turning on the motor changes the reading without moving
the dial? Is there another readout for the longitudinal position? If
so, does that change at the same time?

If there is a second readout, and no change on that, what
happens if you swap the connectors from the two scales? Does the jump
follow the cross-feed scale, or does it stay in the particular readout?

How much backlash is in the cross-feed leadscrew? What the DRO
can tell you is where the cross-feed is -- and if there is backlash, the
cross-feed can move without any change in the dial's reading. (A
relatively new lathe should not have such problems, but it may -- or
even the gibs may not be tight enough.

Anyway -- set up a dial indicator and check whether the
cross-slide moves when you start a cut. If so -- there it too much slop
somewhere.

Note that usually DROs for lathes have a switch for the
crossfeed to either read radial motion, or diameter of material to be
removed (radial multiplied by two). If it is in the wrong position, you
get significant errors. (Some lathe feed dials are designed to read in
diameter changes and others (all that I have) read in radius changes.

Looking at a PDF file downloaded from a Google hit, it is
apparently the 1/2 button. Hmm ... no it is for centering.

Also -- is the DRO powered from the same outlet as the lathe?
If so, what happens if you move it to another outlet.

Also -- check whether either the ends of the scale, or the
pickup head are loose in their mounting to the lathe.

Am I doing something wrong, is ther a fault in the DRO, or am I just
expecting too much from what is a relatively cheap devise?

Any ideas would be appreciated.

Some things above to check.

Good Luck,
DoN.

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