New Shopsmith DC-6000 Dust Collector

[DLB]

I have not made saw dust in significant quantity to have shown evidence of a leak there. I am surprised though to hear that there is no gasket .

I have gotten off that track momentarily. I am trying to understand the gap across the top of the motor housing. My current theory is that when the gap exists there has been an assembly error. Not an error that can be corrected by reassembly though.

I'm not saying there is no gasket, just that mine doesn't have one. My optimism is fading, but I hold out some hope that this, along with the poor machining I presume is unique to mine, is the main problem. (Note- I have made zero sawdust with this thing, I'm recycling pre-upgrade sawdust. It started leaking as soon as I powered it up so I haven't used it in its intended role. Unless you put on a new collection bag, yours is probably similar.)

My current theory on the gap is that the main housing tapers inward toward the bottom and the motor housing design does not takes the taper into account. So when the bottom curve seats (assumes that screw is out of the way) the top curve has a gap. This was there on DC-3300, I photographed the leak for this other thread when I was preparing for this upgrade and the gap is obvious: viewtopic.php?p=287035#p287035

TheMain Housing supports every thing. Obviously the DC3300 was designed to fit. I am not certain that is true for the DC6000.

I don't think the DC-3300 is a great fit here either. The Short Seal is the same PN in both. And I remain convinced that the new motor housing is made from the old motor housing, and that is why it exhibits the same poor fit (the gap). The DC-3300 does fit much better at the inlet, and does not require that foam donut 'seal' (8A, Inlet Seal).

- David

[RFGuy]

I am stating the obvious here but I think it is worth pointing out….if the new blower has significantly more airflow than the old DC-3300 design then leaks will become more pronounced and visible due to the increased airflow. So, leaks that may not have shown up in the original DC-3300 could be much worse with the upgrade.

[DLB]

I apparently do not understand, why not just seal everything with silicon caulk? Or spray foam?

I'm planning to do that (silicon caulk or similar) in several areas. Two areas that I particularly want to improve, the 'large gap' at the top of the motor housing and the foam donut that is unique to the 6000, are too big. That's not hard to solve. The bigger issue to me personally is I'm expecting SS to replace my motor housing due to the poor machining shown earlier in the thread, so I'm waiting. I don't agree this is a kluge, I see it as an improvement over the foam OEM 'seals' for sealing, plus I think there is no OEM seal between the fan and motor housings, but obviously a PITA for repeated assembly/disassembly. (Not much more so than the decomposed OEM seals though).

- David

[DLB]

I had something of an 'aha moment' in the shop today while disassembling my DC-3300 motor/fan to clean out the motor. The motor housing surface that I've been thinking of as flat is not a mating surface in the DC-3300. It is only a mating surface if it is reworked into a DC-6000 motor housing. And it ain't very flat. I now think the extraneous machining marks in the surface of my motor housing are not the true cause of the leak, it would leak there no matter what. Unless there is a seal, and I have already said that mine has no seal. I can see daylight looking through the gaps where these parts go together.

The other side of this coin though is that a leak here cools the motor. When I did thermal evaluation it was with the outer perimeter of this sealed up with duct tape, and the motor got very hot. Too hot, IMO. I'm not loving it sealed or unsealed.

My next step is to put a DC-3300 back together. After that I'll consider an engineering call with Shopsmith. I'll try to post some pics of what I'm seeing.

- David

[dusty]

I went ahead and reassembled mine and allowing the gap across the top of the motor housing to exist. With all of the assemblies and disassembles I have destroyed the integrity of the foam gaskets. Some frog tape took care of those "for now". I don't know yet if I have leaks. I have to put on the dust bag and the filter bag and make some saw dust to verify that.

Later. Maybe yet this week.

I did do one quick air velocity test (my klug test). Where I had fan velocity of 4105rpm (one port open) I now have 6250rpm. If this works according to textbook, all ports open will I will have something like 2400rpm.

Incidently, assembly with the gap the axis line up. II don't believe the engineers intended it to be this way but I'm stuck with it. At least it works. I still consider what I now have to be a klug job.

This is not a done deal. There will be another disassembly to re-gasket and I am looking for a flexible 4" coupler.

[DLB]

Not having my DC-3300 apart recently, I am having difficulty understanding this. What supports the assembly that is not aligning properly?

IIUC the motor 'housing" is attached to the blower housing. The blower is attached to the blower housing(DLB's leak)

WHAT/how is attached to the DC-3300 body?

I want to try to answer this because I am at a loss as to what to do next, and I want to take advantage of jpg's trend of correct answers and seeing something others have missed. But I'm going to change the order:

"WHAT/how is attached to the DC-3300 body?" Molded into the main housing, there is a large "U" at one end that supports the motor housing and a smaller (~4-5/8" diameter) half circle at the other end that the fan housing inlet rests on. Once the whole motor/fan is set in place, there are two screw that go in from the bottom to hold the motor housing down and another half circle that screws in above the inlet. There are seals on all of these interfaces.

"IIUC the motor 'housing" is attached to the blower housing. The blower is attached to the blower housing(DLB's leak)" Correct, on the DC-6000 the motor housing becomes more of a cover over the motor.

"What supports the assembly that is not aligning properly?" I think, mainly because I tried the same thing, Dust was raising the inlet end in an attempt to close the large gap at the top of the motor housing. When he raised it far enough to close the gap, it was no longer completely aligned with the hole in the main housing. I understand why he wants to close the gap, it would be a lot easier to seal, but I think this is just how both DCs are made. Shopsmith chose to fill the gap with a fatter piece of foam, called the Short Seal. I don't like this feature, but I'm not worried about it.

- David

[dusty]

Maybe a picture will explain better than words.
This is the DC-6000 ready for installation

20210728_163214.jpg (268.64 KiB) Viewed 724 times

This is what it is replacing. Note the minimal gap on the far side.

20210730_085738.jpg (323.53 KiB) Viewed 724 times

This is what happens to the intake port if you attempt to minimize that gap

20210825_074928.jpg (116.74 KiB) Viewed 724 times

This the gap that must be filled with a foam seal.

20210728_124918.jpg (389.11 KiB) Viewed 724 times

My frustrated opinion ---
The gap would not exist if the DC-6000 design had taken into consideration the fact the intake port is lower than the axis of the fan and motor. I believe that the design was developed with an objective of using the existing molds to development the Motor Housing. Thast big gap is going to be hard to make air tight.

Compare the 2nd and the last photo, paying attention to the gap. Shopsmith knew this; that is why the kit includes the big thick foam seal. A klug fix in my opinion.

[JPG]

Are the two screws that secure the motor housing on the bottom of the "U""

Dusty are you closing that gap by tilting the assembly(raising the inlet end)?

The only thing that will close that gap is a horizontal shift towards the rear. That however will retract the blower inlet away from the "half circle".

I think accepting the large gap is a necessity if the assembly 'length' is shorter than the DC 3300.

I think proper alignment at the inlet is the overriding need.

Yes thicker 'seal' is cludgy, but anyone have a better 'solution'.

I agree that the fan/housing interface needs a better seal. Maybe that is the place to extend the overall length.

I am assuming the motor housing to main body at the "U" is the same all around(front to rear gap).

[dusty]

Are the two screws that secure the motor housing on the bottom of the "U""
Yes. On the same end as the gap. Prevents any lateral movement.
Dusty are you closing that gap by tilting the assembly(raising the inlet end)?
That will close the gap but it raises the input port which is prohibited.
The only thing that will close that gap is a horizontal shift towards the rear. That however will retract the blower inlet away from the "half circle".
No, not the only thing. Lifting the input poprt end will close the gap.
I think accepting the large gap is a necessity if the assembly 'length' is shorter than the DC 3300.
Yes, without some design change.
I think proper alignment at the inlet is the overriding need.
If not, air flow will be adversely effected.
Yes thicker 'seal' is cludgy, but anyone have a better 'solution'.
I think I do but I'll present that after some testing. I do not like the idea of thicker foam.
I agree that the fan/housing interface needs a better seal. Maybe that is the place to extend the overall length.
The seal on that end is OK if you don't alter the gap.
I am assuming the motor housing to main body at the "U" is the same all around(front to rear gap).
/color]

[DLB]

Are the two screws that secure the motor housing on the bottom of the "U""

Yes, they screw in upward from the outside below the cooling grate.

Dusty are you closing that gap by tilting the assembly(raising the inlet end)?

The only thing that will close that gap is a horizontal shift towards the rear. That however will retract the blower inlet away from the "half circle".

I think accepting the large gap is a necessity if the assembly 'length' is shorter than the DC 3300.

I'm not sure that it is shorter. If I clean all of the decomposed seals off a DC-3300 motor/blower assembly it will slide a bit on the mounts. I haven't tried to measure it carefully, but IMO either version could be a bit 'longer.'

I think proper alignment at the inlet is the overriding need.

Yes thicker 'seal' is cludgy, but anyone have a better 'solution'.

I'm considering a filler plate when I put one together for real. That may be overkill though.

I agree that the fan/housing interface needs a better seal. Maybe that is the place to extend the overall length.

On the 6000 the inlet is an off the shelf 4" hose coupler. (The black piece in Dusty's photo.) A longer coupler or perhaps a piece of 4" PVC would extend the overall length. And could be rounded on the end to better fit the main housing contour, like the DC-3300.

I am assuming the motor housing to main body at the "U" is the same all around(front to rear gap).

Not on mine. Since trimming the protruding screw at the bottom mine seats well at the bottom. I can look through that big top gap and see it. I believe that this is because the main housing is tapered in toward the bottom and the motor housing is not.

My thoughts on those.

- David