If you are looking to engrave cylindrical objects, such as tumblers, mugs, glasses, etc., then you will need a rotary. Several popular types of rotaries are: Chuck, Roller and 4-Wheel. The 4-wheel has the most flexibility out of all the models, but it also tends to be the most expensive. If you are looking for a good quality rotary, that is reasonably priced, and includes personal US support, then you'll want to take a look at the rotary from HM Laser Accessories. You can also join the private HM Laser Accessories group on Facebook to learn more about them. Rotoboss, Cohesion, and Mansfield also make quality rotaries, but from what I have seen, the support is not as good. The HM Laser Rotaries do more work to set up, but it has more options available and the owner will help you get started.
HM Laser Accessories V3 Modifications:
My rotary of choice is the V3 by HM Laser, because it hits a happy medium in terms of price to performance and has good support. My only wish is that it was tool-free. Below are some modifications I made to mine so I don't need to use allen wrenches to adjust it. I also designed and printed a set of 3D spacers which are useful when engraving mugs and other items.
Note: HM Laser Accessories may not provide support with these modifications in place. Be sure to save any parts you remove in the event you need to return it back to its factory configuration.
Download the Rotary Spacers STL Files (Zip file with 6 spacer widths).
Required Components for HM Laser V3 Modification:
On the motor side (right), replace the two allen screws used for the height adjustment with two 12mm Thumb Screws.
On the support side (left), replace the two allen screws used for the height adjustment with two 8mm Thumb Screws. Next, remove the two plastic end caps and corner brackets. Finally, slide the new Inside Corner Connector in from the back, slide the support assembly over the corner connector, and attach using two 8mm Thumb Screws.
Photo of 3D printed spacers. On the motor side, clip the spacer on using small office binder clips. On support side, let it sit on the hexagon roller supports, and float between the object being engraved and the two thumb screws.
Below is sketch that shows how to wire in a switch to toggle between the Y-axis and a dedicated rotary driver.
Rotary Wiring Sketch
How to Laser Engrave Tumblers with an OMTech 4-Wheel Rotary:
The below video shows you the basics to get started engraving tumblers using an OMTech 4-wheel rotary and LightBurn.
Video: Laser Engraving Tumblers with a CO2 Laser Engraver & LightBurn