SHM0609 with 1.5kW HSD Spindle.
Increasing the Z-axis travel.
I had a look at the travel on the Z axis and was a little surprised to find I could lower the collet to the table surface, "before" the travel ran out. I worked out the axis could lower another 20mm (if the table wasn't there ). Given the smallest tool bit I have is ~20mm, the spindle is set ~40mm too low.
The maximum travel the Z carriage can move is ~160mm. The most I could move it was 134mm before the collet nut was touching the table. If I had a small tool bit loaded, then it's really only 114mm of travel. Which is rather pathetic given the actual 160mm travel available.
I removed the spindle mounting plate and machined new bolt holes for the spindle 40mm higher. The result is I now have a spindle that moves from 16mm above the table to 176mm above the table. Perfect result, as with my smallest tool bit loaded I can still machine to the table. I still need to face mill the table to get it level, so I'II end up with a few millimeters more room
The distance between the table and the bottom of the gantry is ~124mm. So now I can load a tool bit 50mm long and still get full clearance under the gantry.
I considered having multiple position bolt holes, but it seemed a pain to align the spindle plate once, and I wan't to thread lock the bolts. So ditched the multiple position option.
Before... 0 to 134mm travel. Usable range, 114mm
After... 16 to 176mm travel. Usable range, 156mm (36% improvement).