dusty wrote:I can understand "Double-Tilt" with the PowerPro but why might I want "Double Tilt" with the older headstocks?
Is more precise extension table alignment the only reason?
I am gonna crawl out on a limb here since I have not actually tried this.
The earlier headstocks do not reverse rotation.
Reversing direction is a 'feature' of both the Mark VII and Mark 7 which both 'double tilt' allowing 'under table shaping.
This is to allow mounting the cutter 'upside down' from 'topside' shaping.
Router bits typically can only be mounted one way in a chuck/arbor.
Router bits therefore do not require reversing direction. The proper cutting direction is the same regardless of above or below table headstock location.
So, routing will work without the headstock reversing direction.
Shaping will also work without reversing headstopck direction as long as the shaper cutter is NOT reversed on the arbor.
That leaves the fence as a thing that may be affected.
On 500/Mark 5 models, the fence is mounted between the cutter and the way tubes for above table routing/shaping.
The 510/20 shaper mounting holes are reversed by reversing the table(the reason for the double gear rack posts as well as the direction of 90 degree tilt).
The Mark 500/Mark 5 shaper fence will mount any where on the main table(the clamping is independent of any holes in the table). This means the dual gear rack is only to provide 90 degree tilt in the direction required for under table routing/shaping.
In all cases the feed direction determines the plow/climb condition.
So if all this is accurate, the double tilt will 'work for all 'Mark X' models as long as the bit/cutter is mounted correctly for the direction(s) the headstock runs.
The reverse run direction is only needed when the cutters are reversed on the arbor. All things 'equal', this also requires reversing the feed direction.
I am not totally 'comfortable' with all this, but at this late hour I cannot see any 'holes' in the 'logic'.
From a 'safety' viewpoint the positions of the fence and the operator and the feed direction can be undesirable.