Update on the DC Collar

Vaughn McMillan

Administrator
Staff member
Messages
36,054
Location
ABQ NM
Some of you might have been following the saga of my new Harbor Freight DC. If not, here's part of the history, and here's the other part. Some of you also expressed interest in the collar that I added when I put in the neutral vane. I can save you some time...it doesn't help, and in fact it blows more chips into the filter with the collar than without.

Here's a video showing the amount of chips falling out of the filter after the DC is turned off, both with and without the collar. Even though the low-resolution video is a bit blurry, it's easy to see clumps of chips falling out of the filter when the collar is installed, and they're not falling when the collar is not there. :doh:

I don't know enough about the aerodynamics involved, but I suspect part of the problem may have been turbulence from all the tabs at the top of the collar. When I removed the filter to take off the collar, there was quite a bit of stuff stacked up that would have slid into the bag freely had it not been for all the tabs around the rim.

image021.jpg

Regardless, the collar is now sitting in the scrap pile. :rolleyes:
 
[size=+1]Vaughn,
I'm glad you posted that! Just last weekend, I installed a 'neutral vane' and a collar in my Penn State 2 hp DC. I immediately noticed the very same effect that you did. About halfway through the 'wind-down' when I shut it off, a huge quantity of chips and dust falls out of the upper (cartridge) area, indicating that it had been rattling around in the upper half of the DC the whole time it was running. I'mm assuming that long runs, using the planer, would accumulate even more debris in the upper area (haven't tried it, just speculating). So...I guess the collar is coming off mine, too.[/size]
 
.... Just one question Vaughn. Did you tapper the collar from the top down or was it the same diameter at the bottom as the top ?

Thanks in advance

Boyd


Some of you might have been following the saga of my new Harbor Freight DC. If not, here's part of the history, and here's the other part. Some of you also expressed interest in the collar that I added when I put in the neutral vane. I can save you some time...it doesn't help, and in fact it blows more chips into the filter with the collar than without.

Here's a video showing the amount of chips falling out of the filter after the DC is turned off, both with and without the collar. Even though the low-resolution video is a bit blurry, it's easy to see clumps of chips falling out of the filter when the collar is installed, and they're not falling when the collar is not there. :doh:

I don't know enough about the aerodynamics involved, but I suspect part of the problem may have been turbulence from all the tabs at the top of the collar. When I removed the filter to take off the collar, there was quite a bit of stuff stacked up that would have slid into the bag freely had it not been for all the tabs around the rim.

View attachment 3863

Regardless, the collar is now sitting in the scrap pile. :rolleyes:
 
.... Just one question Vaughn. Did you tapper the collar from the top down or was it the same diameter at the bottom as the top ?

Thanks in advance

Boyd

[size=+1]Don't know about Vaughn's, but mine is (was) a straight column - no taper. It works (worked) just like Vaughn's, which is to say it didn't work well at all.[/size]
 
.... Just one question Vaughn. Did you tapper the collar from the top down or was it the same diameter at the bottom as the top ?

Thanks in advance

Boyd
Like Jim, I made mine a straight column. I've got the full blow-by-blow story here. I may try a tapered collar sometime if I run out of things to do in the shop. I theory is seems like it'd work, but I'm pretty aerodynamically ignorant. (Sorry to see your results were the same, Jim, but glad to see my results confirmed, too.)

Don, I didn't have time to test with and without the neutral vane, but with the vane, I'm not seeing chips go up into the filter.
 
I have a similar (Grizzly) 2hp DC (Looks like it came off the same assembly line.) I wonder why you added the neutral vane and collar to begin with. Is there something I missed?
 
I have a similar (Grizzly) 2hp DC (Looks like it came off the same assembly line.) I wonder why you added the neutral vane and collar to begin with. Is there something I missed?
The neutral vane has been suggested in the past for this type of collector by several folks, most notably Bill Pentz. The idea is to keep the incoming particles from disrupting the flow of the particles already in the DC. Someday when I have it apart to change the bag, I might try running some 'before and after' experiments with the neutral vane. Mine is a tight fit, so it'll take some hammering to get it out.

The collar was something I saw somewhere in the 'net, and thought it looked like a good idea. Considering the collar only took about 5 or 10 minutes to fabricate and install, I guess it was worth the experiment.
 
This is great, Vaughn!! :thumb: I've had the exact same DC sitting in the corner of my shop for a couple of years now, albeit still green. :D

First chance I get, I'm going make this mod. Can you post a link to the filter cartridge you used? Thanks!!!

- Keith
 
Top