Using a 4" Pad with a PC7336?

joebags · 07-11-05, 08:39

I have a PC7336 which comes with a counterweight for a 6" Pad, if I use a 4" is it necessary to change the counterweight as well? I would think it would be a PITA to have to change not only the backing plate but the coutnerweight as well when I want to go back and forth between pad size.

a.k.a. Patrick · 07-11-05, 09:22

I'd feel more comfortable with a 5", but give it a whirl at low speed and see what you like better! Gradually increase speed...Let us know......

JustinTRW · 07-11-05, 11:28

I use a 5" counterweight with the 4" pads and experience no problems. Quite smooth.

I've also heard some people comment that the counterweight doesn't really do anything. Have 6" counterweight at home and can give it a try with 4" pads if you'd like and see if there is a difference. Could have sworn that my 6" pads were not as smooth with a 5" counterweight, but maybe it's the placebo effect.

- J

Accumulator · 07-11-05, 01:48

I have both counterweights and after playing around with them, I use the 6" weight with all sizes of pads, including the 4" ones.

My basic reasoning is that the foam pads we use for detailing all weigh more than a single sheet of sandpaper, and the original "weight/plate combos" were developed with sanding in mind. Perhaps this is why people decide that "the counterweights all act the same". I dunno, I just can't imagine Porter Cable bothering with different weights if they don't make any difference and *I* believe I feel smoother operationn with the larger weight.

I've never had any problems from running the 6" counterweight with the smaller pads; the problems I've had with bearings/etc. all came from using the 6" counterweight with 6-6.5" pads. This weight with the 4" pads runs nice and smooth, even at speed 6.

Bill D · 07-11-05, 04:14

Same here, Accumulator. I also experience no problems.

joebags · 07-11-05, 04:59

THANKS guys.

a.k.a. Patrick · 07-11-05, 05:11

Larger pads hold more liquid weight, this is why there is a heavier counterweight, to help compensate weight disribution. As pads, weights and backing plates reduce, so should the counterweight. I quote, from Coastaltool.com: "The counterweight is a half-moon shaped piece of metal attached to the rotating shaft of the tool. This smooths 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.
There are two different counter-weights which are clearly marked to indicate use with either the 5" or 6" backing pad. Therefore if you decide to outfit the 7335 5" Sander with a 6" backing pad for sanding or polishing you must switch to the counterweight used with 6" backing pads. The same goes for the 7336 6" Sander. If you decide to outfit it for 5" sanding or polishing you must switch to the counterweight used with 5" backing pads.
I choose to follow this advice, as well as recommended it. Im not here to argue with those who do it different, I have just had success, and figured if it works this way, why dismiss the feasibility of it.