My PC came with a counterweight for 5" pads already on it. I also got a 6" backing plate, which came with a counterweight for 6" pads. When I swapped the counterweights, the 6" weight was loose. The screws holding the 5" weight in place won't tighten up enough to secure the 6" weight. What should I do? Just leave the 5" counterweight on it? I don't want to run the PC with the 6" weight on it knowing it wiggles a bit. I know I can just put another washer on the screws or get shorter screws, but I just want to know if this is a problem everyone has run into when swapping their counterweights. I got the 6" backing plate and counterweight directly from Porter Cable, so I was a bit concerned when the swap didn't quite work out.
question about PC7424 counterweights
- Thread starter mjpd1
- Start date
When I first got my PC I thought the very same thing. I went to put the 6" on and it was loose. But then, I was able to keep tightening the screws until it wasn't loose any more. It's kinda strange, the screws start to feel tight, but then feel like you can still tighten them some more. Maybe someone else can shed some light on this. :nixweiss
Robert
Robert
3Dog
New member
I am curious as to what you all are experiencing. I have seen numerous other threads about this subject. I have had my PC for over 5 years..I use 6", 5" and 4" backing plates on it and never had a problem. Curious minds want to know.
SilverBelle04
New member
mjpd1 said:
I just changed mine from a 5 to a 6 today. You'll just need to turn it just a little bit more. Mine did the same thing.
Bob
JasonD
New member
Could the factory bolts have been installed with a little loctite on them that is coating the unused threads? If so, you would have to push through the loctite before the threads "loosen" at all.
membim
Chadwick's Auto Detailing
Does the 6in counter weight really make that much of a difference? I use the 5in with no problems?
If I'm 'highjacking' this thread, I apologize.
If I'm 'highjacking' this thread, I apologize.
No problem. I've read many "user guides" on the PC7424, and they say you should swap weights accordingly. However, I have a few friends with the PC who weren't even aware there were different counterweights available. They've been using them for years with the 5" weight with no problem. So who knows. I was just trying to do things by the book!
Here's a good article on the PC7424
http://www.bettercarcare.com/articles.php?articleId=47
Here's a good article on the PC7424
http://www.bettercarcare.com/articles.php?articleId=47
togwt
The Old Grey Whistle Test
~One man’s opinion / observations ~
Counterweights:
Is a half-moon shaped piece of metal attached to the rotating shaft of the tool, this smoothes out the random orbit action by providing a counter balance to the elliptical orbit of the rotating backing pad. If you change the pad size you must also change the counterweight or suffer unnecessary vibration and possible damage to the tool. Counterweights are attached with two Torx fasteners; size T15.
There are two different counter-weights, which are clearly marked to indicate use with either the 5-inch, or
6-inch backing pad. Therefore with a 6-inch backing pad for polishing you should use the 6-inch, 0.140 oz. counterweight PN 699933. The vibrations that are generated at higher speeds when using a 5-inch weight and a 6-inch pad are unacceptable for most people. For the 5-inch backing pad (or smaller) for polishing you should use the 5-inch, 0.120 oz PN 874011 counterweight.
A Porter-Cable company representative confirms that the increased vibrations can lead to bearing damage within the PC's drive assembly. My advice, use the right counterweight.
The only exception is when using the 6-inch foam-polishing pad PN 54745 supplied with the machine. Due to its lightweight and the small-diameter backing pad used (included with pad), it can be used with either the 5-inch pad or 6-inch pad counterweight.
~Hope this helps~
Experience unshared; is knowledge wasted…/ Jon
justadumbarchitect * so I question everything *
Counterweights:
Is a half-moon shaped piece of metal attached to the rotating shaft of the tool, this smoothes out the random orbit action by providing a counter balance to the elliptical orbit of the rotating backing pad. If you change the pad size you must also change the counterweight or suffer unnecessary vibration and possible damage to the tool. Counterweights are attached with two Torx fasteners; size T15.
There are two different counter-weights, which are clearly marked to indicate use with either the 5-inch, or
6-inch backing pad. Therefore with a 6-inch backing pad for polishing you should use the 6-inch, 0.140 oz. counterweight PN 699933. The vibrations that are generated at higher speeds when using a 5-inch weight and a 6-inch pad are unacceptable for most people. For the 5-inch backing pad (or smaller) for polishing you should use the 5-inch, 0.120 oz PN 874011 counterweight.
A Porter-Cable company representative confirms that the increased vibrations can lead to bearing damage within the PC's drive assembly. My advice, use the right counterweight.
The only exception is when using the 6-inch foam-polishing pad PN 54745 supplied with the machine. Due to its lightweight and the small-diameter backing pad used (included with pad), it can be used with either the 5-inch pad or 6-inch pad counterweight.
~Hope this helps~
Experience unshared; is knowledge wasted…/ Jon
justadumbarchitect * so I question everything *
I have to disagree somewhat with matching the weight to the backing plate so exactly. For polishing using the foam pads we attach to the PC, always use the 6" weight when polishing because you will get fewer vibrations. In fact, I still like to recommend as light a backing pad as possible (5") with the 6" weight.
Remember that the 6" and 5" counterweights were designed with sanding use in mind, which was the PC's original job. A big foam pad full of polish has more effect on balance than a featherweight disc of sandpaper does once attached.
That doesn't mean that people polishing with the 5" weight necessarily face certain disaster (people did that for years), but it's not the "optimal" set up for both the user and the machine.
(The exception to what I said above would be the tiny 4" "spot pads" sold by CMA of course....)
Remember that the 6" and 5" counterweights were designed with sanding use in mind, which was the PC's original job. A big foam pad full of polish has more effect on balance than a featherweight disc of sandpaper does once attached.
That doesn't mean that people polishing with the 5" weight necessarily face certain disaster (people did that for years), but it's not the "optimal" set up for both the user and the machine.
(The exception to what I said above would be the tiny 4" "spot pads" sold by CMA of course....)