# DA Speed Setting > RPM



## camerashy (Feb 9, 2014)

Could someone explain the correlation between the 1-6 speed setting on a DA and the related rpm please.
Also just come across the term 'Zenith Speed Technique' does anyone use it and what stages of rpm do you use.
Thanks for your help
Dave


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## captaintomo (Nov 20, 2014)

Would also like to know.


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## big dave 666 (Aug 2, 2014)

*Zenith technique*

Type zenith technique with polisher into google and have a look at mike philips reply on autogeek. Thes also a guide to this on CYC, which explains it far better than i can, but this particular technique seems more suited to a rotary. I have used it to good effect with a rotary with no hologams marring or cobwebs left behind


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## stangalang (Nov 27, 2009)

There is no real need to use a zenith point with A) a random orbital machine and B) non diminishing polishes should you use them. You are neither breaking an abrasive down nor worrying about leaving holograms if you don't. 

Also, a random orbital machine is measured in OPM (orbits per minute) not rpm (revolutions per minute), as the spinning is only produced by adding a counter weight


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## Steampunk (Aug 11, 2011)

camerashy said:


> Could someone explain the correlation between the 1-6 speed setting on a DA and the related rpm please.
> Also just come across the term 'Zenith Speed Technique' does anyone use it and what stages of rpm do you use.
> Thanks for your help
> Dave


Common, 'free-rotation' DA's use an electric motor (Running through a right angle gear drive to multiply torque and reduce speed.) which rotates an offset crank with a freewheeling bearing hub on one end and a suitable counterweight on the other. The backing plate shaft is screwed into the offset freewheeling hub, which allows the pad to follow a controlled circular orbit whilst simultaneously rotating at an independent speed determined by the friction and gyroscopic forces on the pad. This motion is referred to as a 'random orbit'. These two separate planes of movement can be measured in the following fashion: Orbit Length, OPM, and RPM.

Orbit Length is determined by how far the freewheeling hub is offset from the physical center of the crank, and controls the ultimate distance traveled by the pad in any given crank rotation. Garden-variety DAS-6 & G220 model DA's have an 8mm orbit length; Rupes models and their copies typically vary between 12-21mm.

OPM stands for Orbits/Oscillations Per Minute, which on these machines is a factor of the RPM of the motor, and changes linearly with the variable speed of the motor. To increase pad OPM's, increase the speed of the motor.

RPM stands for Rotations Per Minute, which on a 'free-rotation' DA is a factor of the gyroscopic forces and friction placed on the pad/backing plate and its bearing hub. To increase pad RPM's, decrease pressure whilst maintaining or increasing the motor RPM's.

One can vary the pad RPM's & OPM's to one's advantage by manipulating motor speed and downward pressure on the machine. Here is a further explanation of some of the physics involved: http://www.buffdaddy.com/files/1519584/uploaded/KBM-Kevin%20Brown%20Method-Machine%20Stroke%20-%20How%20It%20Affects%20Sanding%20and%20Polishing%20Performance.pdf.

As for the Zenith-Point-Method, this technique was popularized by DaveKG, and is very helpful with achieving the best results whilst using traditional Diminishing Abrasive Polishes like Menzerna, 3M, Dodo-Juice Lime Prime, etc. These polishes feature abrasives which start off at 'X'-Size, and end up at a finer grade (Say, P2500 initial starting grade, to P5000 final finishing grade.) due to friction, with a fairly linear decrease throughout their working cycle.

I equate the ZPM to being like slowly warming up the tyres on a racing car to increase grip, allowing you to go faster once the rubber has reached operating temperature, and then making a few slow 'cool down' laps to bring the temperatures down without heat-cycling and damaging the engine/brakes/tyres. One starts off at speed 1 (1800-2500 OPM's) and slowly increases speed with each pass to slowly work some heat into the lubricants until reaching your full operating speed (Around 5800-6000 OPM's at speed 5), which makes them more fluid and gives the polish a longer working time, before slowly decreasing speed again to play the product out and prevent it drying up. This allows you to make the most out of the abrasives, and ensure that they are fully diminished by the end of their cycle for maximum gloss and defect removal.

This, along with the Kevin Brown Method for non-diminishing polishes: http://www.detailingworld.co.uk/forum/showthread.php?t=289564, are the core techniques for machine polisher usage. All advanced techniques build on these two methodologies, which is why it is important to practice them, and develop a foundation of understanding. If you encounter a situation requiring a correctional extreme (Either finishing soft paint, or removing stubborn defects from hard paint; two processes at the opposite ends of the machine polishing scale.), what these techniques can teach you is crucial.

Hopefully this helps... If you have any more questions, please feel free to ask. :thumb:

- Steampunk


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## mohebmhanna (Jul 19, 2011)

Excellent inputs Steampunk as usual.


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## AllenF (Aug 20, 2012)

Recommended speeds are as follows: 
• Waxing & Buffing – 1 to 2
• Polishing & Cleaning – 3 to 4 
• Removing Paint Defects – 5 to 6.
Rpm on a da dosent rally count as it oscilates not just rotates so your looking at ORBITS per minute NOT revs per minute.
The above is ONLY a starting point not gospel some cars may cut on 3 some may wax on 5
Its whatever works to achieve the desired results


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## camerashy (Feb 9, 2014)

Thanks AllenF useful info as a starting point for me


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