ATLAS/DOMMIE OIL MIST SCRUBBER
I have owned my Atlas for over 60 years, and for most of that time I have been firmly convinced the "froth tower" was of little or no effectiveness in controlling oil mist escaping from the oil tank . Thus, having the tank off the machine for a new powder coat finish, I resolved not to let another half century pass without having a look inside to see what Norton was doing to control oil mist. And so, I cut off the cap at the top of the tower and had a look inside. Here is what I found:
The timed breather hose attaches to the lower tube which enters the tower at the base, and then turns 90 degrees downward, terminating at the roof level of the oil tank. Between the lower tube, and the upper vent tube, there is 1 1/2 inches of air....gravity is the principal of operation, but 1 1/2 inch elevation change just will not do the job.
Now I had to close up the tower, and still desired to control oil mist. My solution was to fabricate a scrubber cartridge that is inserted into the tower, and secured and made oil tight by a nut or cap.
The cartridge is as below, and will be explained further below.
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First it was necessary to Dremel grind all remnants of the old tower cap and weld, making the inside of the tower tube smooth and burr free.
Not having the machine tools necessary to cut threads on the exterior of the tower tube, which would also require a nut or cap to be fabricated, I sought someway to apply threads to the mouth of the froth tower tube. I found that a 1 inch conduit compression fitting would slip over the tube.
View attachment 5650
I cut off the lower part off the fitting, leaving only the threaded ring for the mating compression nut.
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The threaded ring is made of pot metal and can be soldered with special low temperature alloy solder, temperature indicating flux, and sufficient skill. Lacking all of the above, I elected to JB Weld the ring to the tower tube. Besides, I feared application of heat to the thin ring would warp it, making the nut bind.
Hint: Apply grease to the threads of the ring, in case you inadvertently get JBW on the threads....that way you can get the JBW off without chasing the threads with a thread file, as I had to do. Get the ring square to the tower tube.
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The scrubber cartridge is fabricated as follows:
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Item 1) is a 10-32 x 1 1/2 machine screw, 2) #10 flat washer, 3) 1 inch Dia. discs cut from 3M stripper pads, 3A) has a notch to clear the exit port, 4) 10 - 32 nut, 5), 6) gasket ...preferably a very compliant material like cork or neoprene, 7) 1 1/4 OD fender washer. Blue locktite the nuts.
Slip the cartridge into the tower tube, and secure with the compression nut. The nut fits between the frame and tool tray with close but sufficient clearance.
View attachment 5655
The cartridge can be easily removed every other oil change and rinsed with solvent. Don't be too critical of the paint on the frame...that is original paint with 50 years and 85K miles of use.
How effective is the scrubber? I have not run it yet, but close mesh filters have been used to scrub oil mist in automotive applications for the last century. I am sure it will be more effective than the "air" filter employed by the boys at Plumstead Road.
Next task: clean up the tank and prep for powder coat. I plan to coat the nut and top washer as well (protecting the threads with high temp. tape).
To fit to a Dommie oil tank, not having a froth tower, weld in a short section of 1 inch OD tube, and replace the Dommie tool tray with an Atlas tray.
Slick
Update: 7.14.17 - I have changed the media to fine mesh and added one more media disc. The extra disc requires the media to be compressed. I do not think this increases the back pressure significantly.
Update: 7.4.20 - Removed the cartridge recently. Found the scubber media saturated with oil, showing that it is effective in removing mist from the vapor. Also, I am not getting the oil mist deposit on my rear wheel.
Comments and questions are welcome.
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