Harbor Freight Rikon Impeller Upgrade – Is It Worth It? #4: Performance Curve Comparisons

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Blog entry by clagwell posted 12-10-2019 08:17 PM 2086 reads 1 time favorited 1 comment Add to Favorites Watch
« Part 3: Help! My motor's smoking! Part 4 of Harbor Freight Rikon Impeller Upgrade – Is It Worth It? series Part 5: De-Constructing the HFDC »

Part 1 of this blog has a chart showing a comparison of the original impeller versus the Rikon. Here’s a more detailed view of the performance of the upgraded unit. This is only an impeller and inlet size change, it’s otherwise completely stock, including the bag filter. Future posts will look at other modifications.

Pressure is corrected to a standard air density of .075 pound per cubic foot to allow comparison with other published data.

I’ve added actual data points to the graph. These represent three separate runs each on a different day over a two week period. The solid line is a simple square law curve fit to those points.


I purchased the dust collector in 2010. At the same time I bought a pleated filter from Wynn Environmental and never installed the bag. After filling the filter almost immediately I realized I needed a way to get better separation as well as keep the dust in the bag after separation. I added a Thein type baffle to the bottom of the separator ring which helps with both of those issues. It also reduces flow. I wanted to know how much reduction I was getting so I made some measurements. I wasn’t really trying to compare with the rest of the world, just with and without the baffle.

I later came across an article from the March 2008 issue of Wood Magazine. Given my somewhat crude DIY test instruments at the time I was surprised to see reasonable agreement between my data and the magazine article. As it turns out that was actually more luck than skill but, oh well.

As in the previous chart the X marks are my data. The solid line however is not a curve fit to my data but rather a copy of the plot from the magazine article, and that’s what I’m going to use in the rest of this blog.


So here’s the net result of the fan transplant:

Note that the original curve is for a 5” fan inlet. The Rikon mod uses 6” inlet.


That Wood Magazine article included curves for a number of single stage dust collectors. The next chart is an overlay of the HF/Rikon curve on the published chart of various 6” inlet units. The HF/Rikon curve is the dashed line.

The HF/Rikon curve has good pressure at low CFM but falls of rapidly at the high end. I suspect that is due to the 5” outlet on the fan housing. I think the other ones all have 6” outlets. I’ll show some more data on this issue in a future post.

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

1 comment so far

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5393 posts in 3233 days

#1 posted 12-11-2019 12:27 AM

Interesting data and one wonders on the return on investment both for dollars and time.

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