I would add some additional observations on all this....First to be clear i did not say that the "Flip" head machines were without problems on the "Z" ways.
I have seen the Flip head machines with the inside way galling.....I own one myself. It does happen.
I would say that it is less prevalent in the Flip head machines than on the earlier 3150 "camel back" machines.
Further,I think the later versions of the "Flip" are the least likely to have the issue.....Believe that Deckel in a attempt to cure the problem changed the heat treatment of the
"Z" ways. Later machines are much harder on the surface than earlier versions. Deckel changed the scraping technique on the later machines as well. Late "Flip" head machines have
a much more aggressive pattern on the slide side .
On my 3150 FP4NC the "Z" way surface was soft enough that scraping with a carbide tool is relatively easy. Good cutting action was not an issue.
However on my 86' FP3NC "Flip" the way surfaces are so hard that the same carbide scraper barley scratches the surface (power or hand)...makes marks but moves no metal at all....
For what ever reason the most issues on the "Flip" machines i have seen has been on the FP2NC's.
And that goes for the problem with the annoying spindle whine as well.
As to gear noise....think almost all Deckels with significant spindle time get noisy.....Its rare to find one that is very quiet. Most of the noise will be generated , i believe from the vertical drive
portion of the gear train. My 3150 FP4NC is a bit noisy when running above 1000 RPM in vertical...However running horizontal at higher speeds its pretty quiet, with very little gear noise. (pretty much just the drive motor)
My FP2NC "Flip" by contrast is much louder when running vertical.....Think in this area its pretty much a coin toss as to what you get.....Hard long work life is likely to produce a noisy machine.
I pretty much ignore it..of just turn up the radio....
Replacement of the gear train to make a machine quiet would represent a huge investment with unsure results....lots of stuff in there that are high cost to replicate....All gear teeth are finish ground and some are integral with needle bearings, and
splines. All the sort of stuff that would make after market replacement hard to replicate at a reasonable cost even if you could broker a group buy....I don't see this as a possibility.
Perhaps coating teh existing gears could help in the noise department...no experience here with that potential remedy...
Think the later machines with the variable frequency spindle drive would potentially be better as to noise since they incorporate fewer gears in the spindle drive, but they still have the vertical spiral bevel gear setup, so no guarantees.
As to the control....there is documentation as to the circuit diagrams, and the boards have discreet components that can be replaced.... Getting older its true, but pretty repairable for most components, just depends on
your level of connection to this system....Believe they can be kept working for some time into the future if desired.
Replacement of the CRT IMO is a must if you are planning on keep a machine for an extended period of time! A solid state display is more reliable (i replaced my video board 3 times before i bit the bullet and replaced all
with an LCD display)
The real advantage to the machine is the reduced temperature of the operators station. I equate this directly to prolonged board life!
Cheers Ross