Ensure mm/min in CNC mode

[blaggacao]

In CNC World, feeds are ipm or mm/min. This is for historical reasons. mm/s is used nowhere that I'm aware of. Let's don't make people's lives miserable.

[T3P3]

Rather than force the switch in CNC mode it would be better IMO to have the option to choose the units that the user prefers

[blaggacao]

Rather than force the switch in CNC mode it would be better IMO to have the option to choose the units that the user prefers

In theory, this sounds reasonable. In practice this would be optimizing for the 0.001% - at the cost of complexities in forcing a completely domain-irrelevant option onto the other 99.999%, roughly :-)

I don't mean to sound dismissive in exaggeration, but the actual reality might be something like 99% vs 1%.

G94 is defined as feedrate per minute since ~1958 and has been that way ever since, worldwide.

[blaggacao]

Let me anecdotally expand a bit to support that claim.

In CNC finding the right mm/min or ipm is actually ranked among the hardest things to get right (ref: https://www.cnccookbook.com/whats-hard-learning-cnc-survey-results/).

Therefore, a lot of people will look through forums to find the correct ipm & mm/min ballpark value for their use case. Most are in ipm, some are in mm/min - none I have seen are in mm/s.

In that context, providing an option adds a practically irrelevant questionmark to an already hard to learn subject. This is bad, because users should save up their valuable focus on not getting confused with ipm & mm/min and finding the correct chipload and speeds for their spindle, machine, material and bit already.

[blaggacao]

Most are in ipm, some are in mm/min - none I have seen are in mm/s.

In that context, what might be practically much more useful, instead, is to show values in ipm & mm/min at the same time, giving the configured option the larger font size, while still showing the other to reassure the user of their own calculus and aid and assist in developing a feeling for both scales while they skim the available domain-specific references.

[T3P3]

I would prefer to get away from two specific "modes" as such and have elements of the UI reflect what the user wants, i.e. be customisable. Lets see what @chrishamm thinks bout this option for 3.7.

[blaggacao]

@chrishamm This now targets v3.7-dev as requested in the forum.