John Doe wrote: Any suggestions on the best or easiest to find rotary tool (Dremel) flex- shaft lubricant? ^^^^^^^^^^^^ This is not directly in response to your question, but I hope it saves you, or others, a lot of grief. I was using a Wecheer flex shaft carving attachment on my Dremel, when it started to make an odd noise. It was still working, and I wanted to get the job done, so I continued to use it, and the drive shaft broke. (It's made just like a Dremel flex shaft.) I pulled the broken end out, but there is no way to get the other half out. The shaft (and Dremel is the same), is closed at the business end. When the shaft breaks, the strands flare out and catch the housing, and there is no way to pull it out.
Fortunately, the thing was under warranty, and I got a brand new one, but I started making phone calls, asking you are supposed to replace the broken drive core. Dremel just told me to send it in for repair. Wecheer told me nothing useful.
My advice: inspect the drive core frequently, keep it lubricated, and always replace it if you even think it MIGHT break. Also, always keep the flex shaft as straight as possible when running it, and NEVER bend it to a tight radius when using it.
Hope this helps.