PC jiggling but not spinning

**lazybum** · 12-01-2004, 12:41 PM

Not sure if this is supposed to happen but when I`m polishing my car with my PC 7336 and the sonus das kit the pad jiggles like it should but it doesn`t spin. Is that normal?

**Jngrbrdman** · 12-01-2004, 12:44 PM

That is pretty much the way they are suppsed to work. Its not like a rotary where it just spins in one position at high speeds. they call these `Random Orbital Polishers` for a good reason.

Fear not. You aren`t the first to wonder if their PC is working properly.

**lazybum** · 12-01-2004, 01:34 PM

Yea, i undestand it doesn`t spin in one place but I thought it`s supposed to jiggle while spinning. Its just jiggling but not spinning at all.

**TW85 HHI** · 12-01-2004, 01:42 PM

Once pressure is applied most or all of the spinning stops.

**Magellan498** · 12-01-2004, 01:44 PM

Your PC can spin, but thats under little to no pressure. Also your pad being off center will make it harder for the pad to spin. Like Anthony said, the PC is not necessarily supposed to spin, it just happens sometimes and does not have the effect of the rotary.

**raymond_ho2002** · 12-01-2004, 02:24 PM

The spinning is an artifact of the "random" motion. I don`t think it is intended.

**gnahc79** · 12-01-2004, 03:48 PM

Physics experts plz correct me if I`m wrong:

A PC oscillates, which means that it goes back and forth very fast. A PC will `spin` when you turn it off, not sure if it spins when you turn it on. The PC is going in one direction right before you turn it off. Normally the PC goes in the other direction (oscillation), but with the power off the pad keeps on going in the inital direction, causing the pad to spin.

**salty** · 12-01-2004, 05:22 PM

Do you find that it will spin, when you go over an edge.

**Scottwax** · 12-01-2004, 05:27 PM

If you just use the weight of the PC, it will spin. A cyclo will spin and oscillate, which is why it is a more aggressive machine than a PC.

**Corey Bit Spank** · 12-01-2004, 05:31 PM

Originally posted by Scottwax

If you just use the weight of the PC, it will spin. A cyclo will spin and oscillate, which is why it is a more aggressive machine than a PC.

Must to rub it in you--you $300 buffer user!!!!

:p

**the other pc** · 12-01-2004, 05:40 PM

Originally posted by Scottwax

.. A cyclo will spin and oscillate, which is why it is a more aggressive machine than a PC.

Do the Cyclo pads rotate freely if the power is off and you spin the pads by hand?

If so then the motion is the same and any extra aggressiveness would come from differences in orbital radius, motor power and speed.

PC.

**Scottwax** · 12-01-2004, 05:50 PM

Originally posted by the other pc

Do the Cyclo pads rotate freely if the power is off and you spin the pads by hand?

If so then the motion is the same and any extra aggressiveness would come from differences in orbital radius, motor power and speed.

PC.

They will rotate freely when the unit is off, but unlike the PC they continue to spin and also oscillate when you apply pressure. Definitely a more powerful motor. I`ve been using it for paint correction and the PC for final polishing. They compliment each other very well.

**Thomas Dekany** · 12-01-2004, 06:17 PM

the pc sure spins when I dry my pads

**jimmybuffit** · 12-01-2004, 07:04 PM

Yeah, but wait a minute!

Remember that the PC is a DUAL ACTION machine.

Use a clean pad, speed #5, a `reasonable` amount of polish, and NO pressure, the pad will spin freely, and `jiggle`.

Apply a little pressure - til the machine begins to bog down - and you`ll see the rotation slow, or stop.

I mark my backing pads with a Sharpie at about 5 points to monitor the rotation...

Jim

**Accumulator** · 12-01-2004, 07:33 PM

Possibly pointless observation: The PC was originally designed as a RO *finish sander*. Used properly, a sander doesn`t have pressure put on it; it relies on (only) the abrasiveness of the paper for its "cut". As soon as we lean on it a bit to better effect paint correction, we`re "misusing" the tool (and yeah, I lean on it too). Sorta plays into what Jimmy Buffit pointed out. Perhaps that`s why the PC seems (to some of us at least) to work so much better for applying glazes and LSPs than for paint correction.

I wish somebody would open up a PC and see how the thing is driven. The Cyclo uses direct gear-drive. No matter how much force you put on it, it acts the same-the heads go around, driven by the gears. The free-spinning heads make it "random" as opposed to being like a rotary. I somehow suspect that the PC uses an elliptical cam rather than gears but that`s *purely* speculation based on how it behaves.

the other PC- Heh heh, we go around and around on this without really figuring it out

but the Cyclo is sure a different animal than the PC, as ScottWax has found out. The fact that he is planning to get a Cyclo to compliment his PC says it all...remember, he`s the guy who did incredible work by hand for all those years. A brief test-drive with the Cyclo and he`s ready to spend some pretty big money on one.