Instruction: Given a question and its related document, determine if the question is answerable by analyzing the information in the document. Output yes if the document addresses the question, or no otherwise.

Input:
Question: can this machine effectively grind down zinc, copper, tin, and aluminum?  also can it buff these metals to a shine?
Document: The packaging of grinding wheel and fiber wheel as pairs: you can get the individual wheels online from MicroMark.com for $9.20 for either. They sell this machine with a different label (and a lot more money - $70).
Compact design and economical bench grinder is used in our machine shop regularly and seems to perform well. Not a heavy duty model and does not always spin up as fast as we would like, but its a steal for the price.
just a basic piece of cheaply made junk tool. It will break after a few uses, and whats the point to that. Also, the price is not that good, for either it's size or functioning.
The housing and the wheel are the same size, hard to grind objects with a wide surfaces like putty knife
This unit is perfect for a hobby like mine. Polish, grind and drill, all with one unit. Compact, but powerful enough for any of my requirements.
This grinder is under powered for what i was going to use it for.the wheels are the same size as the motor so you cannot grind anything that is wider than the wheel.if your working on stuff you can use a dremel on this will work.
This is perfect for what I use it for, which is finishing fine copper jewelry. The only thing I wish it had was a foot speed control peddle.
Fit and finish are a little sad.- - - Pricing - - -I got it on sale for 25. At that price it's easily 4-stars. At 50 buckss, not so much. Places like Harbor Freight sell this, and also the replacement wheels.
I raised the RPM and it worked fine.The tool rest is tiny, and not very strong - but this machine is designed more for free hand grinding than high pressure. I used only one screw to bolt it on so I can use it as a guide to rest my fingers on, and angle it the way I wanted.In summary, this is not the machine you want for general grinding but it is great for special purposes.
Put it up to high speed then back off once the wheel is turning, that reduces the starting load.And that raises a question of speed equivalence. I was a bit disturbed at first when I found the motor slowing when grinding at the low speeds I wanted, there isn't enough power to grind HSS at low speed - then I realized that the speed of grinding isn't the RPM, it is the inches per second (or feet per minute).
Answer: no