Originally Posted by
Ydna
....It's true you could get a vertical mill with a 4th axis "tombstone" laid on its side parallel with the X axis, but using a true horizontal with 4th would be preferable for obvious reasons. Not the least of which is the crazy level of Z clearance you'd need in the vertical machine to make it comparable to a horizontal. To me the vertical with tombstone is a workaround, but is certainly an option.......
This can be a very viable option for moderate volumes, i.e., in the many hundreds to low thousand. ANd it depends on your part size whether you need 'crazy' Z clearances. I have four Super MiniMills with the 4" extension on the column that gives 14" of Z clearance and this is enough to run a HRT 210 with a 'horizontal tombstone'. Not exactly a tombstone because we only put parts on one side, but very often we work on three sides of the part and they come off the machine completed with only one fixturing. The limited X travel does restrict us to 5 or 6 parts per load but because the the fixtures are loaded outside the machine the productivity is very good.
An open mind is a virtue...so long as all the common sense has not leaked out.