DC-3300 Seal Failure

[DLB]

I'm getting my DC-3300 ready for upgrade and noticed this issue. It is the second, two out of two, I've seen with the same problem, but I failed to connect the dots the first time. The first picture is on the cooling air inlet/exhaust vent for the motor on the outside of the DC. The motor should be sealed off from the main air volume of the DC, which is pressurized and hopefully dirty. Note the volume of sawdust that has collected in this area, this is not good.

Intake.JPG (378.13 KiB) Viewed 789 times

In the second picture we can see the reason why the motor inlet is so dusty. The upper seal between the main housing and motor housing, directly above the motor inlet vent, is evidently disintegrating. More of it is missing than is present.

OldSeal.JPG (403.76 KiB) Viewed 789 times

Third and fourth pictures are of the new seal from my DC-6000 upgrade kit. I presume that a new seal for the DC-3300 is similar or identical.

NewSeal.JPG (364.28 KiB) Viewed 789 times

NewSeal2.JPG (360.05 KiB) Viewed 789 times

Watch out for sawdust collecting in this area, especially coming from the DC during operation. The DC-3300 motor is forced-air cooled and the center part of the vent grate shown in the first picture is the intake for that air. On the first case that I worked on, the motor would not start and was full of sawdust, symptoms we sometimes see in a conventional headstock. These seals were all shot, but I did not notice the air gap to the motor and destroyed what was left of them disassembling for access to the motor. I cleaned it out and tapped on it and everything was okay, but I didn't understand where all that sawdust came from. Now I know. Some portion of the collected dust was blowing out through this gap caused by what I think is the disintegration of the seal, and being sucked directly into the motor. (I've seen similar foam rubber like this essentially turn to dust over time.)

- David

[algale]

I would think a solid material, rather than foam rubber, would make a better seal.

[JEFFinCLE]

I was recently in the market for a used DC-3300. On inspecting the first one that I found, I turned it on and dust started blowing out the motor vent area. I pulled the filter bag off and scratched my head at the design, as the seals were completely disintegrated and non-existent. I passed. On doing a bit of research (thanks mostly to this forum) I discovered the issue with the seals. The next one I looked at was the older, original design, where the motor is more than half-way out of the frame and the seal between the chamber and the motor is vastly better. I know the newer model is supposed to be quieter, but I'll take the old one any day.

[dusty]

I was recently in the market for a used DC-3300. On inspecting the first one that I found, I turned it on and dust started blowing out the motor vent area. I pulled the filter bag off and scratched my head at the design, as the seals were completely disintegrated and non-existent. I passed. On doing a bit of research (thanks mostly to this forum) I discovered the issue with the seals. The next one I looked at was the older, original design, where the motor is more than half-way out of the frame and the seal between the chamber and the motor is vastly better. I know the newer model is supposed to be quieter, but I'll take the old one any day.

I know my DC-3300 leaked like a sieve but I just never paid attention to it. It wasn't until I began assembly of the DC-6000 that I became aware. I also wonder if a serious sealing effort would improve DC-3300 perfromance.

[kgfaro]

I used Flex tape on a 25 gal mixing bowl that was leaking it worked great