Review on YON SOU Pneumatic Engraving Pencil Grinder by Mario Beaklini

I had to mount the front push-in fitting and the compressor fitting. The compressor port sealing washer seals without the use of Teflon tape as it has an O-ring. It also came with 2 wrenches to fit collet inserts while holding the coal machine shaft. Both wrenches required a light grind to remove any manufacturing burrs and now fit perfectly. I've uploaded a picture showing how to tighten it slightly or loosen it a bit. Overall this pencil works well. The silver spin speed switch is great for getting the speed you want. The long flexible cable makes it easy to manoeuvre. I put a few drops of compressor oil in the pencil tool before applying pressure to 40-60 pounds during a break. I have nothing bad to say about this item and I hope it lasts a long time. The instruction manual is easy to read and has a good parts diagram for further understanding. The pencil tool came with 2 collets for 2 bit shanks of a common size. Don't waste your collets, they are shorter than our Dremel tools. The included bits are good for beginners. A wide range of accessories with saws etc would be a good investment. I will give this product 5 stars for its accurate design and value. I recommend getting one. This is the workshop foreman.