I can now safely say that I’m very pleased with the new quill, and that it improves my cutting considerably. This now makes my Omni faceting machine almost worth keeping.
I cut a small Afghan Blue Tourmaline this time, using a modified version of Jeff Graham’s Aqua Cisir design. It’s meant for a 2:1 ratio which my tourmaline was close but not exactly. The design is forgiving enough that this was not a serious issue.
As you can see from the photos below, the meets are pretty darned good. Much better than I’d been able to achieve previously on the stock Omni quill, and with much less cheating. I think I only had to cheat less than 1/4 of a division on the cheater at the polish stage – unheard of as i was using a full turn or more of the cheater using the stock quill.
I should point out that my results are cumulative of aligning the rest of the machine first, and now this quill is what seems to have pushed the Omni into an acceptable accuracy. However I have the following advice to anyone who owns an Omni:
- Align your mast asap. This will reduce the alignment problems that come from the mast being off-vertical.
- Tighen the Swing Arm to the point where it is difficult to move. This will reduce the amount of flex in the swing arm caused by compressibility of the plastic disks used as bearings.
- When cutting put a pencil mark on the Swing Arm to remind you of the position it was in. This is important because every time you move the Swing Arm you are changing the alignment of the stone to the lap due to all the accumulated inaccuracies in the Omni’s construction.