Friday, September 17, 2010

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.


  • Andrew said...


    I plan to make this for my sawstop PCS. Question - how did you attach the box to the back of the saw? Thanks!

  • HalfInchShy said...

    I attached it with 3 bolts through the back rail; I had to drill those. I took 4 more photos for you and edited them back into the post so go give that a look. Should be clearer especially the star-knob part.

    You'll like it; have fun!

  • Andrew said...

    Wow, thanks :)

    I plan to buy the stuff for mine this week. I don't love the idea of drilling holes into it, i was planning to figure out some way to make it hang from that angle iron.

    But...I'll probably end up drilling it. Thanks again.

  • Andrew said...

    Hmm, I am still having trouble visualizing what that box looks like. Is it basically hung from the underside of the rail?

    I guess it's tough to see with everything being black.

    The bolts from the star knobs just squeeze the EMT so it can't swing, right?

    Thanks again, especially for the fast response.

  • HalfInchShy said...

    More photos in the post with an ugly fill light that makes it pretty easy to see. I think you'll say 'ah-ha' aloud. :)

  • Andrew said...

    Ah-ha! (ok, not aloud, I'll admit).

    So the box is what's squeezing the EMT, not the bolt itself. Very clever (not that I am surprised). Did you use a T-Nut or something in the front of the box to accept it?

  • HalfInchShy said...

    Just used a T-bolt coming up from below. Just need to keep it from spinning... you could drill out a shallow mortice, use chisels, or cheat since it's shop furniture and just put a strip of wood next to the T-bolt head so it can't spin. They aren't held in place so if you unscrew the star knob, they fall out... so don't do that :) All it takes is 3/4 turn one way or the other to tighten or loosen the contraption. I used 5/16" bolts but it doesn't actually matter; that's just what jig hardware I tend to have around.

  • Andrew said...

    Ah,now that makes sense. I was ready to use an insert nut or something to do it.

    Well I bought my EMT today. I'll build the simple box this week and hopefully be done with the "contraption" by the weekend.

    I'll post some pictures when it's

    And (of course) it will be painted gloss black to match the saw. I mean c'mon!

    Thanks, Paul? Paul-Marcel? What do I call you?

  • HalfInchShy said...

    No problem; would love to see photos of it... maybe take them before painting them as that was the killer for decent photos!

    I have some friends who give me a hard time about painting stuff, but one of them washes his epoxy garage floor on his knees with window cleaner... twice a week. Soooo, it's all good fun.

    I just noticed a photo I should add and will later today. In the article, I described making some clamps of wood for the light arm. Since then while getting conduit for the shop, I found EMT conduit hangers and bought two. Much better than the shop-made ones (that eventually dried and failed). I'll have a photo later.

  • Andrew said...

    Very nice. I think I will leave the light portion off since I have a 4-tube fluorescent directly over my tablesaw. I have two other lights on my ceiling that are normally obscured by my garage doors, so I know what that's like!

    I may also have to steal your idea for the magnetic dust port at some point. When trimming the edge of the boards, you're not kidding. It shoots right out that back-left corner. One cut and I am COVERED in sawdust!

    Thanks again, I'll hopefully have some pictures this weekend.

  • Andrew said...

    Ok, a few days behind schedule...but here are some pics of what I have so far. I made the box out of some doug fir scraps, just glued together. I haven't tried bearing down with the star knobs yet since I just glued it together.

    I found these clamps in the electrical section of home depot...I'd rather not have to drill through the rail of the saw, so I'm going to give these a shot and see how they go just clamping to the rail. A screw goes through the bottom of it and will just press into the rail.

    Thanks again for the design!

  • Andrew said...

    Oh yeah. I also put T-Nuts in the bottom of each hole (not pictured). The 1/4" bolt that I am using through my star knobs will thread right into the t-nut, so no nut on the bottom to keep from spinning. Nor will it fall out if I loosten the bolt too much.

  • Andrew said...

    This comment has been removed by the author.

  • Andrew said...

    Well, the assembly is complete, other than the paint drying in the backyard. I also need to put some wires to hang the dust collection fittings in the back like you did. Also, it's currently connected to my shop vac, need to run a DC pipe back to the dust collector.

    But, the saw portion is basically done. Thanks so much for your assistance!

    Here are some more pics:
    Sawstop DC Gallery

  • HalfInchShy said...

    Thanks for the photo follow-up, Andrew. Looks good! You'll definitely like it; just got to get the blast gate set right to get good flow. Also looks like you found the Barracuda hose; some people who ask me about it don't find it very easily. I got lucky :)

  • Andrew said...

    Hey paul, I posted the project on Lumberjocks, if you want to see it all painted.

    One issue - the way I mounted it with those clamps, the star knobs are sitting slightly proud of the TS surface, which is no good. Thoughts?

    I should have mounted the beam clamps a little higher on the box which would have taken care of the issue. too late to fix that now (short of making a new box). Whoops.

  • Unknown said...

    I am considering adding such a dust collector to my PCS. I had some questions about yours. When I went to The Home Depot, all the pipe I could find was PVS plastic pipe. What is EMT pipe? In your photos, this looks like metal pipe. I would imagine that is a lot more expensive than PVC. Is all that pipe, connectors, etc. lower in cost than just buying SawStop's unit?. Lastly, those bent sections--did you have to do that bending or were those a standard component one could buy? If you bent them, did that not require a special tool at some cost?
    It is an ingenious solution! Nice work!

  • Andrew said...

    George, I bolt one. EMT is in te electrical section. It's metal electrical conduit. The bend elbows and connectors are in the same area. It is over $100 chraper than the sawstop version.

  • HalfInchShy said...

    Sorry for the delay; on a long-weekend vacation in L.A. at the moment, but Andrew hooked you up!

    EMT is found in the electrical aisle. I wouldn't want to make it out of PVC as the EMT is so much stronger and you want that rigidity. Get the compression connectors; they are more expensive, but you only need 3; they are "water tight" (so better for the DC) plus they don't have 4 bolt-heads sticking out.

    Definitely make the box for swinging it away; you need a mount anyway and that mount works pretty well.

    I love it and wouldn't change much, if anything if I did it again.

  • Chris said...

    I really like this design. As I'm building it, I'm having trouble figuring out how to connect the 1.25 EMT to the 2.5 hose. I'm having no luck with fittings and reducers so far. Any thoughts or suggestions?