I remade the one I cracked and I shortened the displacer by about a half inch. I'm getting pretty damn good at cutting this glass! Ill take this post to briefly explain how I cut them on the lathe with a diamond file and to show the reworked and new parts.
|Masking tape is the biggest thing you can do to help yourself since until a groove is established the file wants to slide all around. The gap I leave is not much wider than the width of the edge of the file I use.|
You never want to put any pressure on the file besides what is necessary to keep the file flat and in contact with the workpiece. If you're impatient this may be a bit of a challenge to not put any pressure at all on it, but trust me, its cutting and after a couple minutes itll just fall off nice and easy and there'll be no chips, cracks, jagged or sharp edges, just a beautiful smooth edge. I polish the edge with some 220 grit emery cloth to finish up, seems to work pretty good.
Here's some more pr0n-
|Here's the reworked displacer. I shortened it by ~.5". On the left is the cut end of the new main cylinder, the one I cracked in the previous post. Look at that beautiful edge!|
This is gonna be a pretty fun one to get going. Stay tuned!