This is how the PC really works

[TXfreebirdTX]

There was a thread several weeks ago where someone was concerned because their PC was not spinning after some pressure. This led into a debate amongst a few of us on how the PC 7424/7336 really works. Some are under the misconception that the machine actually is supposed to spin the pad on a single axis like a rotary, or else it is faulty. I emailed Dewalt to ask about how the machine really works, and finally after several weeks I actually got a reply:

Subject Please clarify function of the 7424/7336 Discussion Thread Response (Stacie)03/14/2007 10:38 AM Dear Doug,

The term "random orbit" means the disk moves out of the plane line of the motor. The pad is not connected directly to the motor. The rpm of the pad on a flat surface is 1 to 300 RPM. it is possible there will be no rotation and/or the rotation can be in either direction. This makes the sander much more aggressive than non random orbit sanders without creating the swirl marks one would expect with disc sanders.

One misconception of the 7424 is that it is not a buffer. It is an applicator of the wax/polisher and mimics the swirl motion of your hand while applying product.

Regards,
End User Services

Bumping this old thread back to the top!

I came back here to find out if my 7424 was broken, because the pads just oscillate and don't really spin on the axis if under any pressure.

It looks like mine is fine unless there has been an update to this thread... ?


TX

 

[Rsurfer]

Bumping this old thread back to the top!

I came back here to find out if my 7424 was broken, because the pads just oscillate and don't really spin on the axis if under any pressure.

It looks like mine is fine unless there has been an update to this thread... ?


TX

Try using 4" pads which will rotate. Even the 5.5" low profile pads will rotate under moderate pressure.

 

[Wendell Jarvis]

A rotary is nothing more then a varible speed sander or grinder. What makes it a polisher is putting a polishing pad on it instead or a grinding disk or a backing plate with sandpaper. Sanding a piece of wood to get the scraches (cut marks out of it) is really not mush different then polishing the paint on your car. It does not matter what something was initially designed for or called. Lots of tools have many uses. Both a PC and a rotary can be used as a polisher. They can also both be used to sand a piece of wood and many other uses. Both also have advantages and disadvantages as a polisher over the other. Use what works best for you in the situation you have at hand and your level of skill.

:whs:

 

[TXfreebirdTX]

Try using 4" pads which will rotate. Even the 5.5" low profile pads will rotate under moderate pressure.

Thanks! I plan on trying some 5.5" pads in the future. Right now I kind of like the 6.5" ones even if they don't spin on the axis. The part that hangs over the 5" backing plate, is pretty handy for bending into creases and for fitting between gaps in molding, etc. That may not be the most professional way to do it, but it has been working for me so far.... lol


TX

 

[TXfreebirdTX]

:whs:

Cool... I dreaded the idea of having to stop work on my car just to send the 7424 back.... :cheers:


TX

 

[dublifecrisis]

I find that the PC is most effective (for polishing light swirls out) when just enough pressure is applied to slow the rotation down to where it spins about 1-2 revolutions/oscillations per second. For final passes when the polish is broken down, I lighten up and slow the dial down a bit. I took a sharpie and drew a small black line on both of my BP's so I could always tell when I had the right amount of pressure. Using the 4" pads allows me to push down a little harder. The 6.5" pads, well I pretty much just use them for laying down a coat of wax or maybe an AIO or something like DG105.