I started this to answer your PM from yesterday and then started having issues with Comcast so I was off-line for a while. I see that you started a post in the Knife Repair forums so I will answer it here since no doubt other people have the same questions.
I am not an expert at buffing but I have developed a few tricks that I use in the 12 years or so that I've been repairing and customizing knives.
I have one of those Harbor Freight buffers and I rarely use it because of the speed. I prefer a buffer around 1700 RPM, about half of the 3450 RPM the Harbor Freight model has. When I use the Harbor Freight buffer I use 4 inch and 6 inch muslin wheels. I tried an 8 inch wheel on that buffer and it wanted to fly to the moon! My go to buffer is a 1 hp Jet that runs in 1725 RPMs. I also have two homemade buffers that work very nicely, they are all preferable to me over the high-speed Harbor Freight buffer.
If you want the mathematical explanation I'm sure somebody will give it to you but basically the larger the wheel and the higher the RPMs the more surface area comes in contact with the piece you are buffing in a given period of time. And the more surface area that contacts your work the more friction it creates and the hotter it gets. What I have experienced with larger faster wheels, especially when they are hard, is that the material I am buffing tends to chatter and it does not give me as smooth finish as I would like.
Things that I have learned over the years using a buffer:
1 – The most dangerous piece of equipment in my shop is my buffer. I need to be familiar with all of the safety procedures and proper use techniques and use the guards provided. This is the only piece of equipment in my shop that has the potential of hurling a missile across the room at the speed of an arrow or maybe even a bullet! Always respect the buffer!
2 – When operating the buffer I always avoid loose clothing! I avoid anything hanging around my neck, loose sleeves, an unbuttoned shirt, frayed gloves or anything else because even at lower speeds a buffer can grab a piece of clothing and draw the operator into it almost instantaneously. A frayed glove can get caught and remove the operators finger.
3 – Avoid pushing hard on the wheel. There are exceptions to this but it’s analogous to cutting something with a dull knife, the harder you push the less control you have over the outcome. When you are exerting a lot of pressure on the wheel it is easier for the wheel to grab the work and flip it out of your hands, thus creating the missile situation. But aside from that I get better results on my work by not pressing is hard. Sometimes pressing too hard can “tear” the metal. There are certain types rouge that will help avoid that. I generally consult the catalog of the company I’m purchasing from to see what type of rouge I need.
4 – I have separate buffs for brass and nickel silver from steel buffs. There is a very simple reason for this; steel is much harder than brass or nickel silver. One little sliver of steel embedded in a wheel can ruin a piece of brass that you’re trying to polish. At best it will leave a whole bunch of scratches that you will need to spend a lot of time with to get removed.
5 – I use the harder sewn wheels for cutting and deep scratch removal. After I have the scratches removed for polishing I usually use a more loosely sewn muslin buff ideally with about four sewn rings instead of being sewn in concentric circles all the way out to the edge. And for a final finish I usually have a very muslin buff with a very fine rouge, No Scratch Pink is one I use frequently, for the final polish and gloss.
6 – These are the wheels and buffs I use. I’m sure there are other methods at least as effective probably more so, but this is the order I use from heavy cutting to fine polishing. Note that not every step is appropriate for every material you will be buffing!
A – For heavy cutting I will use a sisal wheel with emery rouge.
B – My next step would be a sewn muslin buff with the emery on it.
C – The next finer step is a sewn muslin buff with black magic rouge.
D – After that I go to a sewn buff with No Scratch Pink rouge.
E – For the final gloss and finish I will use a loose buff with No Scratch Pink.
Step A is something I usually only need to use on steel, rarely on brass or nickel silver.
Step B I will use on steel as well as rough nickel silver and brass.
Step C I use on both nickel silver, brass and steel. I have buff with black magic rouge for steel and one for nickel silver/brass. (Actually I have multiples but that’s not necessary to begin with).
Step D I will use on steel and brass/nickel silver but I will also have a separate sewn buff that I use strictly for bone/ivory/horn. If you buff metal and then bone or ivory you will have all this nasty rouge in the pores of the ivory and in the canals of the bone really drive you nuts!
Step E is my final finish for bone, stag, ivory and horn as well as for brass/nickel silver. (As those are separate buffs!)
Step F I know I didn’t have a step F up above but there is one more buff I use and that is a loose muslin buff that I used to apply carnauba wax on handles.
Step G this is a very special buff that is made from string, not from muslin. The strings are basically loops of the heavy thread. You apply a special rouge for plastic and it does a great job on the various plastics you encounter working on knives. The strings have less contact with the surface of the handle that a muslin would and that translates into less heat and no melted handles.
This is the way it I use my buffers and somewhere there are pictures of a new buffer I built that actually has three speeds. I love being able to use the lower speeds because I think it works better than high speeds and there is less heat buildup.
I do have felt wheels and the lot of other special application wheels but I think you would be able to do most everything with a couple of good rouges and some muslin wheels.
If I were going to set up to buff brass I would use black magic and no scratch pink on a hard sewn or a medium sewn wheel. If you have a hard sewn muslin wheel, you can always soften it a little bit by taking out a couple rows of stitching. In my experience softer wheels tend to make better contact to polish a contoured item as opposed to something that is flat.
In your PM you said you would welcome any advice I can give you. I’m not sure that I am expert enough to say this is the only way to do it, I can just tell you what works for me in all the years that I’ve used it.
I hope this is helpful and if you have any more questions post them here and I will be happy to add what I can. I will however be gone this weekend because I’ve got a knife show so don’t expect any answers this weekend.