This is THE BEST alternative to ANY Dremel!!! Dremel has not altered their product in years. Wen has a separate power on/off switch which is inset to prevent accidental power on. It also has a separate rotary wheel speed control with "click stops." This is also inset. If you've used Dremel products you know that they have only a single slider which boyh turns power on & off and adjusts the speed rather indiscriminately. With Dremel products it's easy to accidentally turn on or accidentally turn up to maximum speed. The Wen comes with the flex shaft at the same price as the Dremel without it. I have to give props to my wife for finding this valuable tool for me! Stephen Johnson
I can answer that you might want the rotary chuck because of your arthritis. Other than that, rotary tools are great for many applications, but they do tend to want to "walk" along the project surface. You have much more precise control sanding, filing and grinding by hand.
There are some diamond-impregnated bits that could grind away at river rock, but the bit will be very hard to control. Even in less challenging tasks the bits often want to "wander" around on the surface. Perhaps if you put the rock into a vise and have a very steady hand, and set the rpm's to the optimum speed you might get good results. It may take a lot of practice.
Your rotary tool is pre-installed with a 1/8” collet and includes a 3/32” collet as an accessory.
Would not recommend, even if the shaft would fit.
I would recommend a small bolt cutter instead.
I would expect a jeweler to need a much more specialized product designed for their trade.