This is not really a chapter in the traditional sense. These two pages contain bits and pieces I have collected in various notes, and all I have done is to summed them up into short questions, under the collective heading Did you know that ? . Of course, there could have been several more pages added, but there are enough subjects covered here already. Use the check boxes to mark the answers you did know, and make an effort to learn those that you did not know.

There is no particular order in the listing.

• G28 Z.. motion (vertical CNCs) will cancel the tool length offset?

• Miscellaneous functions M00, M01, and several others become active only AFTER the programmed tool motion in the same block is completed?

• Miscellaneous function M19 (M20) can be used to orient the spindle?

• Spindle can be oriented at the machine (control) using MDI or a button?

• G41 and/or G42 in a turning program will make a precise contour (providing other settings match)?

• Cutter radius offset G41 or G42 must be programmed together with a D-address?

• G87 fixed cycle cannot be programmed in G98 mode?

• G41 or G42 command cannot be started while in arc motion mode (G02 or G03)?

• Start of cutter radius offset MUST be programmed only while a rapid or linear motion is active?

• Miscellaneous function M99 is not only a subprogram end, but it can also make the main...