Rupes LHR 21ES Random Orbital Polisher - Features & Benefits

[mikemurphy234]

What is he talking about?!?! :Cry:



First off, there is no "factory washer".



Secondly, the washer has Z•E•R•O effect on oscillation speed.



Finally, the washer does not guarantee a specific increase in backing plate rotation.

Thanks Kevin, for saving me the time by answering this in a much simpler way than I would have. When this post showed up in my email I was dumbfounded. Coming from a guy who has used pc`s for years I hope what he said was misunderstood.

[pwaug]

"Isn`t this eliminated by adding the spacer washer as recommended and tested by Kevin Brown??"



This was the question, but the answer (90%/10%) got lost.

The question wasn`t really answered as it seems the question was taken as an affront to their credibility.

[Legacy]

The question wasn`t really answered as it seems the question was taken as an affront to their credibility.

The answer to the question was that the Rupes rep (R&D) or manager stated that by using KB mod washer, the machine would rotate 90% and orbit only 10%. Without the mod, it would be 50%/50% which how the machine was meant to work. I did not dream this up...this statement was either moved or removed. BTW Kevin I may have made a mistake by saying that there`s a factory washer. I respect you as a detailer and in no way am I trying to dis-credit your mod. I`m just posting what I read on AGO that Mike Phillips posted.

[edmund_o]

Great article Kevin! Very informative.



If I understand correctly, the machine will keep the oscillation speed constant with or without load. The pad rotation speed is somewhat controlled/limited through friction between shroud and backing plate. With your washer mod, the energy loss from the friction is now transferred to pad rotation. Will do some testing this weekend to compare with/without the washer mod on pad rotation.

[C. Charles Hahn]

The answer to the question was that the Rupes rep (R&D) or manager stated that by using KB mod washer, the machine would rotate 90% and orbit only 10%. Without the mod, it would be 50%/50% which how the machine was meant to work. I did not dream this up...this statement was either moved or removed. BTW Kevin I may have made a mistake by saying that there`s a factory washer. I respect you as a detailer and in no way am I trying to dis-credit your mod. I`m just posting what I read on AGO that Mike Phillips posted.

Hmm... Kevin Brown, maybe you can ask Marco to confirm exactly what they said to Mike and how it was intended to be interpreted? Might be a "game of telephone" going on here.



I could see it if they said in factory configuration the backing plate rotates once per oscillation/stroke, and the KB mod increases rotation to 9 times per oscillation/stroke (which, even still, doesn`t quite make sense if we are only experiencing a 40-50% increase in rotation) but it isn`t like that washer is going to disrupt the eccentric orbit of the backing plate -- nothing with regard to the spindle offset or the counterweight are being modified, and those are the source of the oscillation.

[Kevin Brown]

I know what Marco meant, as I`ve had off-line discussions and debates to quite a degree.



Marco believes that by freeing up backing plate rotation, there`s a chance that the backing plate will spin unabated, ramping up rotation to an un-stabilizing and potentially damaging or dangerous level. The damage or danger occurs if the machine is throttled up prior to placing it in contact with the paint surface.



Although nobody I`ve ever met starts the machine prior to setting against the paint, this was apparently a concern (for other parts of the world).



As to the percentage shift...



I believe that Marco is trying to say that IF the backing plate were allowed to ramp up its rotation, the rotational ACTION delivered to the paint surface would be DOMINANT over the orbiting action, meaning the rotation would have a larger EFFECT on the paint as compared to the orbital motion. This is an understandable assumption, but one that I believe to be incorrect.



Again, my disagreement is based upon what I understand Marco to mean.



Why do I disagree? Here`s why:



Imagine setting a random orbital machine on a table, backside down (this means that the backing plate`s face would be visible because it would be facing upward). Next, place a level atop the backing plate, and adjust the machine so that the backing plate is set to perfectly horizontal. Lock the machine down so that it remains level, even when running.



IF our machine utilized "perfect" or "drag-free" sealed bearings (a super-low friction bearing that has very low or NO internal resistance), and such a bearing was used to support the backing plate mounting pad, then in theory we could spin the backing plate with a push of the hand, and it would continue to rotate for a very long time. For this discussion, let`s identify such a bearing as a high quality bearing.



If my reasoning is correct... until a lot of weight or pressure or force was placed atop the backing plate, the bearing would remain un-loaded. Only the weight of the backing plate, internal friction (and I suppose gravity) would slow rotation of the plate.



Now things get interesting.



If you turn on the machine, you might expect to see the backing plate immediately start to rotate. The fact is, a high quality bearing (as we`ve defined it) will remain un-loaded or drag-free, just as it was with the machine turned off. So... rather than rotate, the plate would remain still or nearly still, at least until the minute amount of friction present between the balls or needles inside the sealed bearing touch the internal race of the bearing (the race is essentially the "track" that the bearings ride in under a light load, or on under a heavy load). Keep in mind that the bearing`s lubricating fluid can place force against the bearing, effectively "driving" or pushing against the bearings.



Wow, tough to write that part (probably not very clear).



Basically, the backing plate is not going to rotate all that much, even though you might have expected it to.



NOW, what if you unlocked the still-running machine from the table, held it in your hands, and started to violently tilt and shake the machine? How would these motions affect backing plate rotation?



Well... the backing plate`s mass would place a load on the bearing because as you tilted and shook the machine in all sorts of directions, the backing plate`s momentum would fight against your sudden and rapid directional changes (the backing plate would attempt to continue on the path it was traveling, but its mounting stud would guide it in the direction the machine was traveling).



Due to the loading of the bearing, the backing plate would start to spin! If you then stopped the machine and installed a foam buffing pad onto the backing plate, and then re-started the machine again (and resumed your violent tilting and shaking of the machine), you would see an increase in rotation because the added weight and leveraging of the pad would increase the load placed against the bearing.



What do you suppose would happen if you decided to place the still-running machine against a painted panel? Would the backing plate and pad stall, or start to rotate?



It depends. If the pad was placed in LIGHT contact with the panel... AND there was enough drag created by the pad as it contacted the panel, then rotation would slow. As long as the bearing wasn`t loaded to a higher degree, internal bearing friction would remain very low (so there would be very little interaction or contact between the internal bearing, and bearing race). We still have to realize that there`s some fluid dynamics present, so the bearing`s lubricating fluid could affect rotation (increasing it).



What if you placed un excessive amount of pressure against the machine in hopes of squashing the pad and loading the bearing?



At some point, backing plate rotation would stall. But, if you continued to add pressure AND the machine`s motor did not bog, THEN you would see the backing plate ramp up its speed, at least until the bearing`s internal friction became too high (at which point the bearing would become inefficient, and would slow or fail).



Where does this lead? No seriously.. I`m lost now.



Oh yeah!



If the goal was to scrub excessive backing plate rotation during free-spin in a free-air situation, I doubt the premise was a good one. I think the goal was to scrub backing rotation while the plate was under load, during use. After all, it is a fact that when the LHR 21ES is used at high speed, it can become unstable.. If the machine is tilted, or the pad encounters some sort of bulge or flared section of a panel, the machine`s large offset can cause the pad to grab and steer the machine onto its side. Although this instability is not a big or notable issue when using thin or pliable pads, it certainly becomes an issue when using a tall or inflexible pad (such as the Rupes blue pad, or a closed cell dense foam cutting pad).



Oh my gosh, it`s late and I`m punchy. I hope at least some of this makes sense.



Good luck deciphering it all!

[(901)]

You should design/build your own machine and stop promoting others :wink:

[ls7drew]

Can`t wait to get mine!

[autoconcierge]

You should design/build your own machine and stop promoting others :wink:

Especially when you set the market up in the USA, then others had to go "Me 2" to the point disinformation and general "Douchbaggery developed". I am so close to a Jerry Maguire like internet beatdown it`s not even funny........................ and as EVERYone knows I hold nothing back as I do not suffer from "Low T", those that know what they are doing when they read this will be going "Oh s**t we all know if Bob says these things there is a high percentage of guys who will believe him because he tells it like it is.

[RaskyR1]

[B]Especially when you set the market up in the USA, then others had to go "Me 2" to the point disinformation and general "Douchbaggery developed". I am so close to a Jerry Maguire like internet beatdown it`s not even funny........................ [/B]and as EVERYone knows I hold nothing back as I do not suffer from "Low T", those that know what they are doing when they read this will be going "Oh s**t we all know if Bob says these things there is a high percentage of guys who will believe him because he tells it like it is.

I think you know a lot of us feel the same way!

[safetyman2010]

Especially when you set the market up in the USA, then others had to go "Me 2" to the point disinformation and general "Douchbaggery developed". I am so close to a Jerry Maguire like internet beatdown it`s not even funny........................ and as EVERYone knows I hold nothing back as I do not suffer from "Low T", those that know what they are doing when they read this will be going "Oh s**t we all know if Bob says these things there is a high percentage of guys who will believe him because he tells it like it is.

[RaskyR1]

Dana what are you doing in here?

[Asphalt Rocket]

Enjoying a nice read and seeing what Kevin`s thought were on the Rupes while waiting for the garage to warm up to play around with my vette. We have a few of their tools in the shop.

[RaskyR1]

Enjoying a nice read and seeing what Kevin`s thought were on the Rupes while waiting for the garage to warm up to play around with my vette. We have a few of their tools in the shop.

Well it`s good to see you over here again.

[Asphalt Rocket]

Well it`s good to see you over here again.

Check your pm`s on my forum.