18Pcs Pencil Die Grinder Air Tool 1/8" Pneumatic Engraving Pen 70,000 RPM Air Micro Pencil Grinder Kit

This is a 5 star little grinder, probably, a true 70,000 rpm grinder and very smooth. Do not listen to the stupid bad reviews this is a great little grinder..........

I'm a long time Dremel user, I decided to get one of these for the occasion of using it around materials that the dremel might ignite or not be reachable with. The speed control is a lot smoother than I had expected and the form factor is pretty great. It also comes with two collet sizes that allow you to use Dremel accessories with it. I found it seems to work its greatest using the wire wheel cup attachments! So it'll likely be my go to for light rust removal or detailed polishing work.However there are a few elements you need to know:1. There is no way to tell what speed you're at, you go by sound and feel, be aware that many attachments have a suggested speed to be used at, this thing far exceeds those suggestions and can damage or wear attachments, so you'll need to make fine adjustments and test your work surface (as you would with any tool).2. The device suggests (by the presence of an odd oil bottle...that has no oil) that this tool needs tool oil for pneumatic tools. I ended up just dripping a few drops in the end then running it several times when I first got it. But the oil bottle doesn't seem useful as there is no suggested oil rates or intervals in the documentation. So I just go with my standard that you need to oil every 20 minutes of continuous use (for now). If I was doing heavy work, I'd likely oil a few drops every 10 minutes. I'm oiling through the large hose as I'm not going to take off the rear Pen connection to oil, that would be a bad thing because this device uses O-rings for seals instead of pipe thread sealant/dope...so messing with the O-rings is likely to affect the seals. So I'm just dropping some oil through the disconnect fitting. About 3 drops every 20 mins of continuous use, as no suggestion was given in the instructions.3. Usage, if your a late-model Dremel user, you've been spoiled by electronics throttle compensation. When a modern power tool bares down into a workpiece, it often speeds back up to compensate so you get an even, consistent, RPM. That won't happen with an air tool, it will bare-down and slow down, so you then have to lift it up and increase RPM and then bare back down into the work. For things that require very fine control (engraving, sanding, grinding) this is an big issue for me and too risky with my ability. So when testing this I went for polishing and wire wheel cleaning applications...which it does VERY WELL. So that's what I've decided to use this for, rust cleaning and polishing. Because those application s require a light touch with consistent pressure without much material removal (work).4. Lastly, air usage. I have a large portable Makita MAC5200 compressor. It claims it's a 3HP unit that can do 90 PSI @ 6.4CFM, this tools claims it only needs 4.3CFM @ 90 PSI. However, this tool depletes my compressor tank from full to kick-in (loader loads) very quickly. While the compressor is running it does keep up with the tool! However...it can never get ahead of it so the motor would run too long if I didn't stop the tool. Even larger electric compressors (like my model) are only built for 50% duty cycle. So while I can technically produce enough air I cannot rest enough to stay with my specified safety margin for my compressor. If you have a gas-power compressor this isn't an issue. But for an electric compressor, continuous air application this is a problem.This little pen still uses a huge amount of air, for short jobs, I'll be fine. If you were doing serious work with this I think you'd have to worry about sizing your compressor to keep up with this tool and still be within it's duty cycle.Overall, I like it, but you really need a very large air compressor for anything more than a 3 minute job. Even though the CFM rate is low, you need to take into account your storage size and recharge time.

Good value for the price

I had to assemble the front collet fitting and the compressor fitting. The compressor fitting washer sealed without the need for Teflon tape as it had an O-ring washer came on it. It also came with 2 wrenches for mounting the tool bits on the collet while holding the collier shaft. Both wrenches needed to be lightly sanded from production burrs and now they fit fine. I uploaded a picture showing the easy way to tighten or loosen a bit.Overall this pencil tool works good. The silver rotating speed switch works great for getting the perfect speed you want. The long flexible cable is easy to maneuver around. I put a few drops of compressor tool oil in the pencil tool before running 40-60 lbs of pressure during break in period.I have nothing negative to say about this item and hope it lasts a long time. The instruction manual is easy to read and it has a good parts diagram for further understanding. The pencil tool came with 2 collets for the 2 common size bit shafts. Don't lose the collets, they are shorter than our Dremel tool ones. The bits included are good for starters. Having a large accessory kit with saws, etc., would be a good investment. I am going to give this item 5 stars for a precision design and value. I recommend getting one. It is workshop keeper.

80,000 RPM I think not. There are much better deals out there for the same item. Returned

Freeing a fossil from the hard rock of the surrounding matrix is tedious and delicate. The 70K RPM pneumatic solution here simply has more 'vaporizing' speed and torque than a friction-bound flex shaft dremel attachment.Better than expected.

Leaks a massive amount of air. Bits burned out super fast

Works better than other engravers.