SawStop Overarm Dust Collection (with light!)

Since writing this entry, I rolled a video giving a tour of the final assembly including the router wing, dust box, and custom power connection used to power the whole thing with 1 cable.  This article is still what you want for assembly details, but the video gives you a better idea what it will do.

Over on the WoodTalkOnline forum, Brian Q and I were exchanging ideas for the SawStop.  In my case, the router wing with dust box (I blogged in more detail here) and in his case his version of the SawStop Overarm Dust Collection.  I believe he's making my dust box and I just finished his overarm guard.

SawStop sells an overarm guard, which is what started the discussion, but it's $200, which is a little steep for what it is.  Brian's post on WTO describes how he did his and here I'll describe my version.

First, a view from the front then details of the build and special features.

The arm is made of 1 1/4" EMT conduit mounted on the back fence rail; it swings up to the far right side of the table keeping this addition out of the way for any width cut.  I added a boom arm with a florescent light to give better lighting on the business side of the table.  Though I added a lot of lighting to the shop recently, the garage door is directly above the saw when it's open; with the exception of summer, my garage door is always open!  This will help.

It was important to be able to stow the collection arm when using the router table.  For some operations, it isn't a hinderance at all, but for running long molding, it's in the way.  This picture shows a view from behind where I'm loosening a star knob...

...rotating the unit down...

...into a stowed position where it is still attached but completely out of the way.

The main component is the J-loop of EMT shown here.  The loop is what reaches above the table.  The straight is what is in a holder I'll explain later and allows the rotation.

The pieces are connected using a water-proof compression-fit coupler.  There are other couplers with set screws, but they press against the conduit and could open leaks.  A water-proof couple looks better and likely holds the vacuum better.

The long part of the J fits into a box attached to the back fence rail.  While it is difficult to see here because I had already painted it black (yeah, I paint shop stuff), it is just a long box with an inside dimension to just fit the 1.5" OD EMT (1.25" is the ID).  The outside face of the box has a portion of the side removed, 2 holes drilled through that side, and star knobs attached.  When the star knobs are tightened, that side squeezes down on the pipe to keep it in place.

Here are some additional closeups:

Note that I drilled 3 holes into the back rail fence to attach the box.

And a closeup of how the star-knob screw passes through.

The following three have an exaggerated fill-light on them so you can see the ends of the box in case the description wasn't clear:

The box simply squeezes the EMT to keep it from spinning; very effective.

This one is from the other side of the pipe from where the last photo was taken; you can see this is just a square column made to fit the pipe perfectly then a side had a kerf cut put into it to allow you to squeeze the pipe.

The end of the J attaches to a 2.5" hose that joins the main 4" DC feed at a 4-2.5 Y junction.  Between that junction and the connection to the saw cabinet, I put a blast gate.  Naturally, I wouldn't shut off access to the cabinet, but this lets me close the gate slightly to increase the flow to the collection arm.  As it is, the flow is significantly better than my previous make-shift setup, but close the gate a bit and it's a regular vacuum up top.

The hose at the top of the J to the blade guard was a lucky find at a pool supply store.  The hose is 36" long with a 1.25" connector on one end that fit perfectly into the blade guard; the other end fits overtop the EMT conduit perfectly.  I believe it was a Barracuda hose.  Regardless, they have the right size hose and rubber connectors at a pool supply store.

The boom arm for the light came out well as it adds the perfect amount of light without a lot of glare on the cast surface. The arm itself is just a stick of pine I had laying around.  I made two pipe brackets that slip tightly over the J loop with a 5/16" bolt poking up through the boom arm.  Two knobs make locking it down and removing it pretty easy.

Addendum: the brackets I made of wood eventually dried, got loose and became a nuisance.  While in the conduit aisle of the borg (where the EMT is), I found two EMT hangers and replaced the brackets.  Much nicer, much easier, and quicker to remove if you want to.

The previous picture also shows how I snaked the lamp cord through the conduit to keep it from being in the way. Here you see it pop out the other end just before the connection to the 2.5" hose.  I simply drilled 5/16" holes for the wire (be sure to completely de-bur and smooth the hole from both sides so it doesn't abrade the cord!).

The lamp cord was in no way long enough to make it to the plug so I needed another 12' of extension.  What I did is use connectors used in power supplies; you can get them at Fry's Electronics.  I had some laying around.  Cut the plug off the light's cord, cut the socket tail from the extension, thread the extension through the conduit then wire the connector to the ends (if you do this, make sure you keep hot-to-hot).  The picture shows the light, connector (and it's fittings), and a pack of neoprene washers that I used everywhere to keep knobs from vibrating loose.  Overkill, I know.  Should I ever want to remove the boom arm, I just unscrew the knobs and disconnect the wire.  Very quick.

Overall, I really like this system.  I get better lighting, the dust hose doesn't get in the way of the cut (my previous hack...), far far better suction at the blade guard, no loose hoses behind the saw, and easily stowed to not impede certain routing operations.

Thanks to Brian for the initial ideas - especially the use of conduit and pool hose! - as it got me to fix a nuisance and gave me something simple to do in a too-hot shop.  Thanks, too, to Andrew for asking questions about things not that clear in the text so I beefed up the photos.