Whats the best dust boot? has to be one of the most frequently asked questions in the CNC community. People provide a variety of answers. Until recently, I said it was the PwnCNC v9. Many people say it's the Nighthawk. I've used both, but both had issues that I couldn't get over.
So, I decided to design my own. I call it the Big Suck. It's big and it had a rumble that reminded me of a muscle car the first time I used it. Because it sounded so cool, I decided to benchmark it's performance compared to the others.
In this post, I'll go through my testing and show which dust performed best and by how much. I'm sure I'll be ripped to shreds by trolls and non-trolls alike for my testing procedure, for being biased, the the test equipment, being fat, needing a haircut, etc.
That said, I tried to be as fair as possible during the testing, but I'm sure there are more scientific testing methodologies. I go on record now saying these performance results are specific to the test installation. Results in other configurations will vary, although I bet they're generally consistent.
Let's get to it.
The Test Environment
My shop has a ClearVue CV1950 running the whole shop. There are 6 trunks with a total of 16 tool gates. During the test, I left one additional tool gate, on separate trunk from the CNC, open. This will reduce the air flow at the CNC and simulate a very realistic scenario where I'm running another tool while the CNC is operational.
I tested four cases: Nighthawk, PwnCNC v9. PwnCNC v9 with the Offset Adapter, and the Big Suck.
I measured the peak air flow with a BTMETER BT-100 handheld anenometer. I placed the BT-100 flat on the spoilboard and lowered the spindle until the bottom of the collet is 55mm from the BT-100. I then adjusted the boot such that the bottom of the brush was 1" from the spoilboard, which gives enough room to fit the meter under the brush, emulating our stock.
Test Case 1: Nighthawk
Peak ft/min: 1850
Peak CFM: 88.43
This is the first dust boot I bought. I was unhappy with how I had to remove it when I wanted to mount something to the front of the spindle mount, notably, my J-Tech laser. I also didn't like how I had to get an Allen key out to make adjustments to its position, as the thumbscrews can hit the frame on the Elite. However, I like how it supports quickly changing the brush length with a different magnetic bush plate. All in all, it's a good boot, and I still use it for my rotary, where I can't give up the Z clearance for a rear-mount dust boot.
Test Case 2: PwnCNC v9
Peak ft/min: 708.7
Peak CFM: 33.88
For me, this boot solved the Nighthawk's two drawbacks. It offer much better visibility and I love the magnetic front. It makes tool changes easy with excellent access to the collet.
I was surprised by its relatively low performance. I repeated this test a few times, to be sure.
Test Case 3: PwnCNC v9 with Offset Adapter
Peak ft/min: 748.1
Peak CFM: 35.75
When I added a larger drag chain, I designed the Offset Adapter so the dust hose didn't rub on the drag chain's trough when the X moved. It solved that problem, but seemed to hurt the performance a little. Around this time, I noticed how the v9 often left a gap between the bottom of the spindle and the top of v9, allowing air to get pulled in from on top of the boot rather than below.
I expected this result to be worse than the stock v9, and I repeated this test to confirm my results. I suspect the more curved nature of the offset improves airflow over the harsh 90 degree turn without it.
Test Case 4: Big Suck
Peak ft/min: 2165
CFM: 102.58
I designed this boot to address the performance issues I noticed with the v9, and to make it easier to swap brush lengths, similar to what the Nighthawk can do.
I was surprised to see it perform better than the Nighthawk though.
Test Case 5: Nighthawk redux
Peak ft/min 1988
CFM: 95.03
When the Big Suck beat the Nighthawk, I looked closely and found that the Big Suck had a 1/4" shorter brush installed. To compensate for that, I re-ran the Nighthawk test after lowering the boot by 1/4" to compensate. This gives the Nighthawk the advantage of a slightly longer brush, but the bottoms of the brush tracks are at the same height in this test, which is more important.
Results Summary
| Nighthawk | PwnCNC v9 | PwnCNC v9 w/ Offset Adapter | Big Suck | |
|---|---|---|---|---|
| Peak CFM | *1988 | 708.7 | 748.1 | 2165 |
|
CFM |
95.03 | 33.88 | 35.75 | 102.58 |
| Z System | Variable | Fixed | Fixed | Fixed |
| Mount | Front | Rear | Rear | Rear |
| Facilitates Filming | No | Yes | Yes | Yes |
| Maximizes Z Clearance | Yes | No | No | No |
| Bocks Spindle Mount Accessories | Yes | No | No | No |
| Easy Swap Brush Lengths | Yes | No | No | Yes |
| Supports Large Drag Chains | Yes | No | Yes | Yes |
Conclusion
I was surprised at how effective the Big Suck was. I expected the Nighthawk to have permit more air flow. Now, based on performance, and based on the various other features, the Big Suck is the definitely the best dust boot. The Nighthawk is still the boot I'll use for my rotary, but for every other reason, I prefer the Big Suck. In my mind, the Big Suck. The v9 is no longer my favorite dust boot, the Big Suck completely outmodes it.
Links:
Nighthawk: https://www.solafidedesignskc.com/product-page/80mm-spindle-with-4-inch-dust-collection
PwnCNC v9: https://pwncnc.com/products/dust-boot-v9?_pos=2&_sid=05b0e020b&_ss=r&ref=qpV7vrEk5xLGzo
Offset Adapter: https://uglydogwoodshop.com/products/pwn-v9-dst-hs
Big Suck: https://uglydogwoodshop.com/products/big-sck-dst-bt1
BT-100: https://amzn.to/4clasLS
Some of the links above are affiliate links. I get a very small amount from purchases of those items via these links. I appreciate when you use them, but I'm also ok if you choose to source gear elsewhere.