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Arbor Nut Catching Experiment


I dropped my arbor nut the other day, while I was changing the sawblade. Of course, it fell down the dust collector pipe. This is not a happy event.

I had recently changed the flex dust hose under the Table Saw to 4-inch PVC pipe. Fortunately, I did NOT glue the joints as I nearly had to take it apart. Equally Fortunately, I managed to just loosen the pipe, pull it off the saw, and tip it and release the arbor nut.

This is a rare occurance for me. I am very careful with how I change the saw blade. There is NOT lot a lot of room for my hand. I slip one hand down and always keep one finger over the end of the arbor shaft, while spinning the nut off or on with the other hand. (this is after loosening it with a wrench, of course. I spin the nut off, and keep the finger in place until it is free and then pinch the nut with my fingers to remove it.

Nevertheless, accidents do happen and once or twice a year, I may fumble and drop the nut. Usually the DC is turned off. This time the DC was turned on, but fortunately (again) the nut was heavy enough that it was NOT sucked all the way down the pipe to the Dust Collector.

The arbor nut impacting the Dust Collector impeller would be what we like to call "A Very Bad Day".

I hit on the idea of trying to add powerful rare-earth magnets inside the tablesaw body to try and catch the arbor nut if (when) I next dropped it. This would mean, of course, that now I have to intentionally drop the arbor nut. Several Times. It needs to be tested!

You can purchase rare earth magnets from Amazon, or from Lee Valley Tools or other stores. However, I work in IT as a day job, and I have collected various old computer Hard Drives over the years and can extract free magnets by ripping open the cases. Ideally you want an older big hard drive, as the newer small modern drives have smaller magnets. In fact, within a few years I expect this will no longer be an option as computers are moving more and more to solid state storage. But, I digress.

So I now had several free large rare earth magnets.

I taped three of them down inside the cabinet of my Table Saw. The dust port is directly under the saw blade, and the arbor nut in my saw is on the left side of that, as you look at this picture. (I have a left-tilt saw, so as you stand at the saw, the arbor nut is on the right side. Please don't be confused)

The idea is that the arbor nut should(?) usually(?) drop down to the side and strick the wood base in my saw and not drop straight down the dust port. That is what my experiment is trying to determine.

Of course, I don't want to keep disassembling the DC hookup. So I tied some fine fishing string to the arbor nut, and looped the end of it over the saw fence. I wanted something as light as possible so that it would hopefully not impede the arbor nut as it fell.

(And yes, I know, I could have just disconnected the DC pipe for this test... I just didn't think of that at the time I was making the video. Oh well.)

I then started attempting to realistically fumble and drop the arbor nut. And the very first time, it went straight down the DC pipe. But after that, it hit the magnet. Each time I had to come around the back of the saw and pull the magnet free of the magnets. I couldn't just pull on the string as the magnets were too strong. The fishing line only helped when it went down the DC piple. I repeated this Seven times, and hit the DC port 3 times, and was grabbed by a magnet 4 times. Better than nothing, but not perfect. I wanted perfect!

I decided to add a fourth magnet. This time I wanted it directly IN the Dust Collector port. I experimented with attaching a magnet to a board and then reshaped it like this, so that it could install down a bit into the port. I positioned a bit to one side. I positioned it on edge as I do not want to restrict the air flow at all.

Here is a top-down photo directly down through the throat of the tablesaw. It shows the fourth magnet in the airstream. I also took off the tape and semi-permanently installed the three other magnets using screws. This also allowed me to position them a bit closer to the edge of the DC port.

I then continued my experiments with dropping the arbor nut. I positioned a gopro camera inside the tablesaw to give a different perspective. You can just see my other camera positioned outside the saw in the upper part of this photo, just left of the sawblade. It was very challenging to film this whole experiment.

The final result was that a magnet captured the arbor nut 18 times (including once or twice on the magnet in the air stream) and it fell down the Dust Port 5 times. This works out to a 78% success rate. This also includes the first seven set of drops listed above, and I think that the magnets now are positioned better.

Still, I was hoping for perfect, and only got 78%. That is better than nothing, but I'm still a touch disappointed. I am now going to just live with this for a while and see. I will try to remember to update this web page in about six months. It might take that long before I again accidentally drop the arbor nut.

And I've already had one person suggest some sort of a mesh. I'd like to test that, but it needs to be small enough to catch the nut, but large enough to not clog with sawdust. Not sure where I could find a 6x6 inch piece of fence like that. I might in future try soldering some copper wire into a grid to make my own mesh -- probably not until the first time I drop the arbor nut and it goes into the port.

Some of the Tools/Supplies Used In This Project: (Affiliate Links)

Rare Earth Magnets
(Also available at Lee Valley Tools, or other Woodworking stores.)
Long Ranger Dust Collector remote control switches

As an Amazon Associate I earn from qualifying purchases you make using my affiliate links.


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See Also:

Worst job in my shop

Table Saw Splitter