mistake I will not make again

[James Baker SD]

Upgrading my dust collection along the recommendations of Bill Pentz. Tonight I cut a 6" diameter hole in the cabinet of my PM-66 (to go with the 4" port on the Shark Guard). I used a 6" hole saw driven by an 18V drill. I will never try that again. My body is still shaking from the vibrations. I did get the hole through (and the drill still runs :-) ) so next step is to drill the mounting holes for the 6" flange adapter. Should be a little easier job. Hope to give it a trial test this weekend.

James

[Joe Jensen]

I drilled a 5" hole in the lower base of a PM66 with a corded drill and it was a chore. I'm impressed a cordless drill survived. The base on mine was like 3/16" thick.

[Van Huskey]

Bill causes a lot of pain! Good thing is now that pain is behind you. Good luck with the rest of the uprades.

[Dave MacArthur]

That dust port on the PM66 is a real pain... located way down at the bottom of the cabinet, it's like PM never thought that anyone would ever want to mount the saw on a mobile base--the dust port is too low and blocks the saw from settling down in angle iron.

And of course, I bought the Powermatic mobile base made by them, specifically FOR the PM66, and it doesn't work... Had to lay a 3/4" ply bottom in there first, then mount saw on top.

Good work sawing that hole, I took one look at the gauge of steel and said, "that 4" hole will do..., I'll put an Exactor or SharkGuard on top!"
:)

[Erik Christensen]

when i put a 6" hole in my robland saw base - even the Milwaukee 1/2" drill was going to take forever despite a brand new bi-metal hole saw blade I purchased just for this purpose

then I remembered I have one of these and the job was instantly easy, fast & safe - the right tool makes ALL the difference

[Paul Johnstone]

I think the standard recommendation is to use 5" duct on the bottom, and 4" for the Shark.. If you go with 6" on the bottom, either it's too big of a pressure drop or not enough air flow for both (I forget the technical reason).

You can get a 6" to 5" reducer for the bottom.

[Brian Cover]

I think the standard recommendation is to use 5" duct on the bottom, and 4" for the Shark.. If you go with 6" on the bottom, either it's too big of a pressure drop or not enough air flow for both (I forget the technical reason)..
Using a 6" in place of a 5" will slightly increase CFM, but will also decrease FPM. The slight loss of velocity will affect the ability to suck out large chips. It is a constant balancing act between the two, you want less restriction and more CFM that a larger pipe offers, but you still have to maintain a minimum velocity to have effective chip removal.

[Dave MacArthur]

Has anyone rigged up an effective inside-cabinet dust collection shroud for the PM66? It doesn't really matter if you have a 2" or a 10" hole in the side of the PM66 cabinet, if it's debouching upon a 3 foot open cabinet inside, well away from saw dust production or point-of-impact from the blade. The airflow speed drops to squat as soon as it enters the larger area.

What is REALLY needed is some way to shroud the bottom of the blade, so that DC airflow is delivered from the cabinet port directly and in a restricted manner to the area around the blade where the dust is generated.

I've been inside that PM66 cabinet many times with my head, trying to figure out a reasonable way to make dust shroud for the blade, but haven't come up with anything good short of a two-piece plastic casting up there...

[Phil Thien]

Just a reminder of a pretty clever technique to make things go faster with hole saws.

Start the 6" (or whatever sized) hole. Then use a 1/4" or 3/8" drill bit to drill a relief hole or two that "kiss" the kerf the hole saw made. This will give chips a place to exit the kerf, instead of being held in the kerf by the hole saw.

[James Baker SD]

I've been inside that PM66 cabinet many times with my head, trying to figure out a reasonable way to make dust shroud for the blade, but haven't come up with anything good short of a two-piece plastic casting up there...[/QUOTE]

Dave:
I've spent hours looking into my PM-66 trying to figure out what I could do. Seems you would need a small hood connected close to the blade and a flex hose to the dust port. The blade moves from center of cabinet almost to touching the wall as you tilt it (not to mention that the motor moves down into the cabinet taking almost all the interior space).
Not being able to figure out something good is why I went with the 6" port in the side of the cabinet, higher up than the original to try to get a high air flow at least somewhat near the blade.
Maybe I post photos this weekend when I get it done.
James

[Cody Colston]

My Griz 1023 has a 4" dust port. I have 6" duct run to within one ft. of the 4" port before transitioning. I've thought about enlarging the 4" port to a 6" but haven't done so, thinking that one day I might want an overhead blade guard/DC and that the 6" in conjunction with the 4" on the blade guard would be too much.

I have an Oneida 2hp commercial cyclone and all of my ducting is 6" PVC. Do you think it will maintain efficiency with a 6" port below and a 4" port above the blade? I'm worried about not having enough CFM for both ducts and enough velocity to move the bigger stuff from the cabinet.

[Phil Thien]

I have an Oneida 2hp commercial cyclone and all of my ducting is 6" PVC. Do you think it will maintain efficiency with a 6" port below and a 4" port above the blade? I'm worried about not having enough CFM for both ducts and enough velocity to move the bigger stuff from the cabinet.

If you found that to be the case, you could experiment with opening your blast gates a limited amount. Once you find the spots that work best, drill a hole and add a machine screw so each time you open the gate, it will only open as far as you want it.

[Alan Schaffter]

The place to start is with the fan curve of the DC, then add up the static pressure resistance of all the flex, pipe, and fittings between the saw and the DC (The new Wood Magazine has a nice example). Apply the total SP resistance to the fan curve and see what kind of CFM results using different ports. Also, check to see if you have sufficient velocity (to keep the dust in suspension) by dividing the CFM figure you determined by the pipe cross-sectional area- you are looking for somewhere near 4000 FPM.

All this presumes you have a fan curve for your DC. If not, you can see if there is one for a similar system (same hp motor and same diam. impeller) on Bill P's or Oneida's website that will get you in the ballpark. Remember it is not one CFM that works and one that doesn't. It is a sliding scale. Your goal should be the recommended CFM for collection at a TS - see Bill's site. It lists OSHA numbers of 440 CFM from the bottom/back plus 350 from above for a total of 790 CFM and a velocity of 4000 FPM for good collection. Pretty tough to achieve these numbers, but if you have less it only means you will collect less fine dust, it is not the end of the world.

I think the ideal internal TS configuration would be a fairly tightly shrouded blade, a shroud that directs the dust at the port, and cabinet inlets that that direct take-up air at the blade. Remember do not close off all the misc cabinet openings - the air being withdrawn by the DC must be replaced 1 for 1. The cross-sectional area of all the holes in the cabinet must equal the area of a properly sized port. Anything less, and you are hobbling your DC.

[James Baker SD]

Here is the result of my retrofit of a PM66 dust port. One picture is inside the cabinet showing the hole for the new dust port. Hardest part by far was cutting the 6" hole with a hole saw on a battery drill. (maybe hardest part was deciding where to put the new hole :)) I adapted the overhead boom from an Excalibur guard to connect to the SharkGuard (much better collection than the original guard). The main dust port is closer to the blade than the original 4" port so hopefully that will help some. I have sealed off the original port, but plan to connect the 4" hose to it when I remove the SharkGuard for dado cuts or other non through cuts.

All in all I am pretty pleased with the results. Very little dust inside the cabinet and none on top of the table. Hopefully I am getting those dangerous fine particles as well as that was the main reason for the retrofit.

James

[Alan Schaffter]

Are you going to try to add a sloped floor, maybe something made from hardboard and sealed with caulk? It can be flat or if you are good drawing a making 3D stuff a sloping chute.

[James Baker SD]

Alan:

The cabinet already has a sloping floor along each side feeding the original 4" port in the center of the back. I placed the new 6" port above the slope on one side both to avoid cutting into the slope and to get the new port closer to the blade.

There is so little room to install anything in there that I am not sure if I can do much more. The 5HP motor consumes almost all the interior space when the blade is tilted to the max 45 degrees. The only option I see would be something attached to, and moving with, the center trunnion.

I do not mind occasionally vacuuming out visible chips that don't get collected (so far the collection is very good, but not perfect), it is the dangerous to the lungs, fine particles I am trying to capture. My pulmonologist ordered me to buy a better dust collection system or find a new hobby, that was the motivation for dumping my old PM 73 and replacing it with an Oneida Cyclone. I am trying to follow Bill P's guidelines for the European Medical recommendations opting for overkill when in doubt.

One other thought, the TS seems pretty good right now, but it is only the 2nd machine I have retrofitted. I think I should upgrade the others to more than their single 4" port before refining the TS any more. Could be wrong here, but the planer and bandsaw both spew out the dust pretty badly.

James

[Alan Schaffter]

One other thought, the TS seems pretty good right now, but it is only the 2nd machine I have retrofitted. I think I should upgrade the others to more than their single 4" port before refining the TS any more. Could be wrong here, but the planer and bandsaw both spew out the dust pretty badly.

James

I would have put the outlet so the sloped floor feeds it. It is easier to enlarge the 4" port than making a completely new 6" one. Remember the suction in the cabinet draws the dust already in the cabinet, it does almost nothing to prevent the blade tips and gullets from carrying dust out the top of the saw. To catch that you need an over-blade shroud. So what I am saying, is since the cabinet is under suction, the dust in the cabinet stays there until it is sucked up by the port or settles on the cabinet floor, so there is really no need to have the port close to the blade. On the other hand, there is really no reason to get in the cabinet and clean the stuff not sucked up either, at least not until the pile gets so high it reaches the motor and belts- that could take years.

I would upgrade all your ports to 6" . Those machines also generate dangerous dust. Remember, what you see is the generally safe stuff, the dangerous stuff is pretty much invisible until it accumulates. And if you dig into Bill's site you will see it takes VERY little of it to exceed max recommended concentrations.