PM 66 Dust Collection issue

[Harold Weaver]

Well, I have a quandary with my 1972 model PM66 that I need opinions on. I restored this saw within the last couple of years from theground up. Once the saw was reassembled and tested, I moved on to the next machine I had in line to restore and didn’t think too much of the overall issues with the saw regarding the lack of a motor cover, dust collection, etc… After several uses, it was apparent that I did not factor in the dust collection capability on this saw. It can really generate some saw dust.

With that said, I have now started to review this issue.This particular saw will need a motor cover, either homemade or one of the ABS aftermarket ones. The biggest issue however is the 4” port size (I really needa 6” one), plus it is mounted on the bottom rear plinth of the saw. Not the best place for one to be sure. It is compounded by the fact that the mobile base rail blocks the chute because it is so low. I can resolve the issue withthe mobile base with using ¼” thick flat steel stock to replace the rear rail anduse longer bolts to secure it which would clear the 4” port up for use. Every machine in my shop is on mobile bases so that they can be moved around. Sitting the saw right on the floor is not an option. Thus, my predicament. The way Isee it, I have several options here.

Option 1 would be too pull the saw all the way down to the empty cabinet and install a 6” port on the back of the cabinet higher up and plug off the 4” port on the plinth. It also does not have a pan inside, so Iwill need to sit the saw on a plywood base inside the mobile base. This would require molesting a pristine cabinet to cut a 6” hole in it. Not my favorite choice.

Option 2 would be to install a 6” port onto the bottom ofthe motor cover, whichever way I decide to go on the cover and still plug the plinth 4” port. However, I am not sure how effective this would be as far as collection would go.

Option 3 would be to make an MDF copy of the front cleanout dust door with a 6” port on it to collect the dust from there. But I believe this route with the hose sticking out at the front would be cumbersome as faras using the saw and having the hose in the way of your feet.

I am all about keeping my machine intact, so I am not necessarily in favor of molesting a perfectly good cabinet. Any ideas or recommendations would be appreciated. What have you guys done in these situations?Any ideas I am not thinking about?
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[Jesse Busenitz]

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Here's a pic of my homemade motor cover. I basically cut a curve on the two 3/4" sides and then kerfed a piece of 1/4" ply to bend around it. I've thought about going to a 6" port sometime and closing up the cabinet some but haven't gotten around to it.

[Kent A Bathurst]

I'd suggest first things first, and see how it goes. I'm not necessarily convinced that you must have bigger than 4".

Make the changes you describe to the mobile base. Inside the cabinet, add a floor that slopes from the front of the saw down to just below the dust port. If you are really handy, you can even add triangular "gussets" to add slope from the rear corners down to the sloping floor.

See what's what.

I don't know where you draw the line on keeping the saw original, but the next step is to control/improve the airflow in the cabinet. Typical things to do [made a world of difference on my Unisaw]:
1. expandable foam between the cabinet and the table. MIght find huge gaps all around there.
2. caulk/seal the sloping floor pan[s] added above.
3. close off any extra holes in the cabinet -- used for bolting on other components/accessories/etc.
4. use magnetic sheet to cover the travel slot for the height adjustment - where it rotates for miter cuts.
5. Now that you have basically all air infiltration closed off, you need to open up enough to supply the volume leaving to the DC.
6. Some will enter thru the blade slot.
7. The rest you can make up by cutting horizontal slots in your new motor cover. This provides the necessary airflow, plus blows the dust off the motor/trunnion, and cools the motor.

You can use mag tape or masking tape to monkey with the openings in the motor cover, to get it dialed in a bit. You can also do the same thing with the height adjustment travel slot.

Basically, stop all air infiltration, and then add it back where you want it, and in the volume up want.

You'll be surprised at the results.

[Steve Peterson]

I have a 2005 PM66 that shares the same problems. I have the original dust cover, but the 5hp motor hits it at certain tilt angles. I like Jesse's custom built cover.

My saw has the standard 4" port. This does OK, but sawdust always piles up in the bottom. It's never a problem and at least it should always keep the sawdust away from the moving components. I am not sure if a 6" port would do much better. There are so many large holes around the handles that it seems nearly impossible to pull sawdust away from the blade.

I use a sharkguard above the table with a 4" port to catch most of the airborne dust. This does a much better job than any under-table suction.

Steve

[Henry Kramer]

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Harold,
Not the best photo (I am away on bus right now or I would take a better photo) but you can see what I have done to my PM66. I raised up the 4" port about the mobile base. There is a 1/4" plywood false bottom added inside directly underneath the port. I also have a Shark Guard with a 2 1/2" port above the blade that is not shown. You can barely see in the photo that I have a steel OEM motor cover. The bottom of that cover is open however if you want dust/air to go out there has to be a way for air to come in. Between the 4" bottom port, the 2 1/2" Shark Guard port the Super Dust Deputy that you see and a Jet AFS 1000, I really don't have a huge dust problem. So that's my set-up on my 1976 PM66.
I agree with your assessment on option #3 that having a port and hose coming off of the front access panel would be cumbersome (if actually not dangerous).
Hank

[Tom M King]

dust collection works great on this old Unisaw. I made a motor cover that accepts a 12x12 furnace filter for the intake. Every crack on it is sealed up with Blue masking tape or something. I have to change the masking tape when we tilt the blade, but it's really no big deal. This is one of our jobsite saws, and portable dust collector is 3 hp four bagger.

[jack duren]

You will collect some dust regardless. We have a Delta 12" at work and has two 4" pipes but its still has some. We don't have to do any extra cleaning unless its clogged.. My Delta has an angle floor and unless something gets trapped between it and the DC its generally very clean...

[Rick Potter]

Since you are trying to keep the integrity of the restoration, may I suggest you give this a try first. If it is not satisfactory, you can always start cutting.

Put a plywood floor on the current mobile base, thick enough to raise the saw high enough to access the original port. Then use a 4 to 6" adaptor at the saw. I suspect it might just work. If not.....eh, haven't lost anything.

Rick

[Scott Stafford]

I've had my PM66 for about twenty years and have tried numerous dust abatement ideas. Here's what I've come up with that works pretty well.

First I put a piece of 3/4" plywood under the machine before I put it into the mobility base. This lifted the machine far enough that the 4" dust port cleared the back edge of the mobility base. It also sealed the bottom of the saw. Actually, before setting the saw in I got some putty-like material and put it around the perimeter to assure a tight seal. This is the ribbon shaped stuff that is used for sealing cracks when insulating your home. It comes in rolls. So that made the bottom of the saw airtight.

Next I bought a 9" x 12" sheet of 1/8" thick flexible magnet. Got it from Amazon for a few bucks. I cut it down to a functional size and use it to cover the gap beside my height adjustment crank. When I want to tilt the blade I just reposition the magnetic sheet and I have one for the other side of the crank for this occasion. When not in use it just sticks to the side of my saw.

I also cut a tight fitting piece to encircle the tilt adjustment crank as it had a large gap around it.

Those steps helped the most.

I played with putting a slanted bottom inside the saw to funnel the dust like the PM2000 has, but after all the fussing I've found that just letting some sawdust build up inside the saw builds the same sloping funnel and has the same effect.

Lastly I bought an Excalibur saw guard with table top dust collection built-in. It works okay, but not great.

The dust collection system is a based around an old Oneida cyclone.

I would not increase the port to 6" unless you have a monster of a dust collector. I think the velocity of the 4" port would be more beneficial than the area of the 6" port. I come off the factory 4" port with a four foot length of 4" flexible hose and then adapt to 6" right at my metal spiral pipe.


Best of luck,

Scott in Montana

[Harold Weaver]

Thanks to everyone for the ideas. I think Scott and rick had similar ideas to what I was thinking initially. Plug the bottom of the saw before putting it in the mobile base with plywood and run my 6" hose to the saw port with a 6 to 4" adapter and see how it works out. I may also have to put a wood spacer between the saw and the right side of the base to get the port more centered to miss the corner bracket as you can see from the photo, its blocked there too as it is off centered.

[Tom Clark FL]

One more photo? Bought this Powermatic used in the mid 80s. Motor cover is a simple rectangular box. Should be easy to make one out of plywood.

[Bruce Darrow]

I get good collection out of my 66, but I went the route of cutting holes in the cabinet: 6" hole in the right side, 1" slots in the left side at (shop made) floor level for "air sweep" effect, Shark guard w/ 2 1/2 port above, factory 4" port blocked off. Still get some slight deposition in the corners, but it doesn't interfere with anything.