allenk4
In time out
- Mar 12, 2013
- 4,845
- 0
[QUOTE=swanicyouth;1099942]If you go on his website, Buffdaddy, it explains it well. It's under where you would go to purchase the Rupes machines. I don't want to be quoting him, but he uses the analogy of sanding a very small area. If sanding a very small area, the sandpaper would clog up with the sanded debris. So, clogged up sand paper (or a pad - it's an analogy), would not cut or finish as well.
If you polish a larger service (or use a larger orbit) with the same piece of sandpaper, there is more area for the sanding debris to be dispersed off the sandpaper (or pad). The increased speed of motion also helps to keep the pad clean. That is supposedly why larger stroke machines have the ability to cut faster and finish better. The percentages of all this I don't know. But even if it's just a few percent, sometimes that can make a significant difference in detailing.
I also BELIEVE he touched on this in an AMMO NYC podcast talking about residue control and paint polishing - but it may have been elsewhere - so, I'm not sure about that.
My interpretation is likely very crude, but it's how I think of it.
Again, I didn't figure out or come up with any of this, I learned it all from Kevin Brown. All credit to KB.[/QUOTE]
That makes even less sense.[/SIZE]
I cannot think of a scenario where the math works on this.
Same sized piece of sanding paper used on a larger area should accumulate more of whatever is being removed (CC or wood).
For example:
If you run a piece of sand paper over a 1 square foot area and remove 1 milligram of material the same piece of sand paper would remove 2 milligrams of material from an area twice the size.
Regarding, "The increased speed of motion also helps to keep the pad clean." This might apply to a rotary that throws the removed material outward. But a DA pulls everything to the center of the pad. Also, only the outer 13mm of the total orbit is moving faster than the same sized pad on a machine with an 8mm orbit.
"But even if it's just a few percent, sometimes that can make a significant difference in detailing." You have much better senses than me, if you can perceive a 2% difference.
I have read KB's writings:
KBM - Kevin Brown Method
The Random Orbital
Machine Stroke - How It Affects Sanding and Polishing Performance
He actually says that when applied to sanding:
It is important to also note that since the backing plate would not have extended movement as would a long stroke machine, abraded residue and sanding debris (such as dislodged abrasive particles) might not clear away from beneath the sanding disc.
It seemed to me that he said the opposite about small stroke machines and small areas:
"Factually, a small stroke machine does confine sanding to a smaller area. This means that for a given amount of time, sanding of any one point will be multiplied. If you plan on using the machine to sand or polish items diminutive in size, a small stroke machine is the way to go."
KB's assertion about large stroke also assumes the exact same OPM will be used with both machines. Turning the speed up even slightly on a shorter stroke machine would negate that 2% advantage.
"Otherwise, a machine featuring a large stroke delivers increased speed of backing plate motion using the same RPM setting."
KB's argument is that the increased speed makes the machine more difficult to control and cause more fatigue. If my math is correct...I don't think anyone could tell when the machine is running 2% faster.
If you polish a larger service (or use a larger orbit) with the same piece of sandpaper, there is more area for the sanding debris to be dispersed off the sandpaper (or pad). The increased speed of motion also helps to keep the pad clean. That is supposedly why larger stroke machines have the ability to cut faster and finish better. The percentages of all this I don't know. But even if it's just a few percent, sometimes that can make a significant difference in detailing.
I also BELIEVE he touched on this in an AMMO NYC podcast talking about residue control and paint polishing - but it may have been elsewhere - so, I'm not sure about that.
My interpretation is likely very crude, but it's how I think of it.
Again, I didn't figure out or come up with any of this, I learned it all from Kevin Brown. All credit to KB.[/QUOTE]
That makes even less sense.[/SIZE]
I cannot think of a scenario where the math works on this.
Same sized piece of sanding paper used on a larger area should accumulate more of whatever is being removed (CC or wood).
For example:
If you run a piece of sand paper over a 1 square foot area and remove 1 milligram of material the same piece of sand paper would remove 2 milligrams of material from an area twice the size.
Regarding, "The increased speed of motion also helps to keep the pad clean." This might apply to a rotary that throws the removed material outward. But a DA pulls everything to the center of the pad. Also, only the outer 13mm of the total orbit is moving faster than the same sized pad on a machine with an 8mm orbit.
"But even if it's just a few percent, sometimes that can make a significant difference in detailing." You have much better senses than me, if you can perceive a 2% difference.
I have read KB's writings:
KBM - Kevin Brown Method
The Random Orbital
Machine Stroke - How It Affects Sanding and Polishing Performance
He actually says that when applied to sanding:
It is important to also note that since the backing plate would not have extended movement as would a long stroke machine, abraded residue and sanding debris (such as dislodged abrasive particles) might not clear away from beneath the sanding disc.
It seemed to me that he said the opposite about small stroke machines and small areas:
"Factually, a small stroke machine does confine sanding to a smaller area. This means that for a given amount of time, sanding of any one point will be multiplied. If you plan on using the machine to sand or polish items diminutive in size, a small stroke machine is the way to go."
KB's assertion about large stroke also assumes the exact same OPM will be used with both machines. Turning the speed up even slightly on a shorter stroke machine would negate that 2% advantage.
"Otherwise, a machine featuring a large stroke delivers increased speed of backing plate motion using the same RPM setting."
KB's argument is that the increased speed makes the machine more difficult to control and cause more fatigue. If my math is correct...I don't think anyone could tell when the machine is running 2% faster.
