Review on YON SOU Pneumatic Engraving Pencil Grinder by Deejay Allard

I have been a long time Dremel user and decided to buy one of these to use with materials that could catch fire or be out of reach of the Dremel. The speed control is much smoother than I expected and the form factor is just great. It also comes with two collet sizes that allow you to use Dremel accessories. I've found this works best when using spoked wheel mounts! So I'll most likely resort to light rust removal or detailed polishing. However, there are a few things you need to be aware of: 1. It's impossible to tell how fast you're moving, you go through the noise and feel, be aware that many attachments have a recommended speed thing that goes well over beyond these recommendations and may damage or wear the bits, so (as with any tool) you will need to fine tune and inspect the working surface.2. The device says (by the presence of a strange oil bottle that contains no oil) that this tool needs tool oil for pneumatic tools. I ended up just dripping a few drops and then running it a few times when I first got it. A bottle of oil doesn't seem to help, however, as the documentation doesn't list recommended oil rates or intervals. So I'm just sticking with my standard that you need to grease every 20 minutes of continuous use (for now). If I worked hard, I'd probably oil a few drops every 10 minutes. I lubricate with oil through a large hose as I will not be removing the rear oil grip linkage, that would be bad because this unit uses o-rings instead of pipe thread sealant/additive. O-rings can affect the seals. So I just drip some oil through the isolation fitting. About 3 drops every 20 minutes with continuous use as the instructions do not specify.3. Use: If you're on the latest Dremel models, you're in for a treat with electronic throttle compensation. When a modern power tool impacts a workpiece, it often accelerates to compensate, giving you a smooth and constant speed of rotation. This doesn't happen with an air tool, it'll be exposed and slower so you'll have to pick it up and rev it up and then get back to work. For things that require very precise control (engraving, grinding, grinding) this is a big problem for me and too risky with my skills. So when testing, I decided to polish and clean the spoked wheels, which is doing VERY GOOD. For this I decided to use it, cleaning and polishing rust. Because these applications require a light touch with constant pressure without much material removal (work).4. Finally the use of air. I have a large Makita MAC5200 portable compressor. He claims it's a 3 hp tool that can handle 90 psi at 6.4 cfm, while this tool claims it only needs 4.3 cfm at 90 pounds per square inch. However, this tool empties my compressor tank from full to boot (bootloader loading) very quickly. As long as the compressor is running, it keeps up with the tool! However, it never happens, so the motor runs too long if I don't stop the tool. Even larger electric compressors (like my model) are only rated for 50% duty cycle. While I can technically produce enough air, I can't rest enough to meet the specified safety margin for my compressor. If you have a gas compressor, this is not a problem. But for an electric compressor, continuous air supply is a problem. This little pen still uses a lot of air, but it's enough for short jobs. If you were serious about using it, I think you would have to start thinking about the size of your compressor to keep up with this tool and still stay within its duty cycle. Overall I like it but you really need a very large air compressor for more than a 3 minute job. Even though CFM speed is slow, you have to consider your memory size and loading time.