PM 66 Dust Collection

[Carl Schellenberg]

I have been meaning to ask this question for some time. I have Powermatic 66 with a six inch hose on the lower dust port and a 4 inch hose on a shark guard over the blade. All this goes to a large Oneida cyclone. I am pretty well eliminating dust outside of the cabinet of the saw. I certainly can tell the difference if I saw something without turning on the dust collector. My problem is on the inside of the cabinet. Coarse saw debris collects on the bottom of the base. The 6 inch port does not appear to collect this coarse saw dust.

Is this normal? I suppose I should be pleased that most all of the dust is captured within the cabinet. I have been wondering if there is something I can/should do to pick up the coarse stuff.

Thanks
Carl

[Dave MacArthur]

Carl,
I have seen one PM66 where the owner installed an internal ramped board sloping from front to back and meeting the rear cabinet at the 4" opening, to keep the large chunks from falling below the intake.

An additional thought--6" port plus 4" port seems like an awful lot of cross section! If your Oneida is running a 7" port and mainline, then the total cross sectional area for your tool should be about 7", as I understand it. 6" duct has 113 sq in, 4" has 50.24 for a total of about 164 sq in, while 7" duct has 153sq in. The increased area, combined with the drag drag going from the 7" mainline to the ports, could drop the airflow speed (not CFM) down below what is required to keep the large sawdust entrained in the airflow.

Just an idea to check out, but you obviously have enough CFM to get the dust, but not enough FPM to keep the big stuff up--recommend you check out Bill Pentz' site where he discusses the differences in those two; I might try running the shark guard at 3". But first I'd build a ramp inside the cabinet!
http://billpentz.com//woodworking/cyclone/index.cfm

[Chris Rosenberger]

The coarse dust collects in the bottom of my PM 66s also. It is not a big deal to me. I made a scraper & every so often just push the dust to the port by hand. It only takes a couple of minutes to clean the bases.

[Lee Hingle]

Carl,
I have a PM66 (2001) also. Mine has a 4" DC outlet though. Did your saw come stock with a 6" hole or did you modify the 4" hole? If you enlarged the hole, could you elaborate? I would like to run a 6" line to my saw as well.
Thanks,
Lee

[Carl Schellenberg]

Lee

Sorry I misspoke. I meant the line size rather than the port size. Your right it is the standard 4 inch port with an adapter to a six inch line. Sorry for the confusion

Carl

[Lee Hingle]

Hi Carl,
No problem. I was thinking of using a 6" DC line with a wye and add another 4" hole above the present one - I figure two 4" holes is almost as good as one 6".
Lee

[Russ Buddle]

With my Unisaw, the heavy sawdust settles in the bottom. When it reaches the bottom of the port, it is also sucked away with the fine dust. It will only fill to a certain level, then the DC will remove the excess.

[Mike Gabbay]

Carl - If the big stuff is in the corners then I would say that's normal. The airflow may be bouncing off the sides and not getting into the corners.

Have you tried closing down the 4" overarm line to try and increase the flow into the lower part of the cabinet? It could be that you are oversized with a 6" and 4" line coming off the 7" main as Dave points out.

[Steven Wilson]

Carl, that's normal. Even if you enlarge the hole to 6" you still aren't flowing enough air to evacuate the cabinet. Now, if you had a 15hp DC and a 10" port (or 2) to your cabinet then you just might flow enough air to collect everything. What you have now is about as good as it will get with that cabinet saw. To get better you really need to work on the inside of the cabinet to get the hose up close to the underside of the blade. It's a design problem with most American style cabinet saws. At leaset Powermatic has an easily accessable cleanout door. I use to just run my dc and brush the chips to the back at the end of the day.