Sunday, September 26, 2010

Using the KM-1 on a Table Saw

The Bridge City Toolworks KM-1 is a clever instrument for perfectly sizing a dado, groove, half-laps, or anything, really, if you treat it as an instrument for perfectly calculating an offset.  Visit the linked page for Bridge City's description of it, or, if you're not the type to "read it for the articles", watch the video of how it's used.

I'm currently making a simple cabinet for inside a closet.  This will be a wonder of plywood case construction with plywood shelves dadoed into plywood sides.  That said, I will be using the KM-1 liberally to ensure that I get exact dados for the "nominal 3/4" and "nominal 1/2" ply.

In the demonstration video, the KM-1 is registered against a stop block on a fence used while cross cutting to create the half-laps.  Naturally you can do the same on a table saw crosscut fence, but what if you're using the rip fence as I will since these sides are 4-5' long by 22" deep?  All you need is a stop block of sorts for the KM-1 to register against.

This is my stop block for the table saw along with a MagSwitch from my magnetic feather board and the KM-1 (I feel as though I should have anodized my MDF jig, but I digress...)

The MagSwitch has two flat sides so I get a very snug fit and it locks the jig to the cast iron like a rock.  Use the shoulder of the jig to register the KM-1 for the first cut...

...the flip the KM-1, move the fence, and make your second cut that will finish the perfectly fitted dado.

I have a router table in the extension wing so the MagSwitch won't work out there.  However, my fence rail is steel so I can move the jig there when I need to be out 22" or further.  Here it's shown with the KM-1 ready for the first cut...

...and flip it and move the fence for the second cut.

When I documented how I did a walnut inlay into cork flooring, I described how I used the KM-1 with the Festool OF-1400 router to make the inlay groove exactly match the inlay pieces.  Basically all you ever need is a stop block of some kind.  This MDF jig for the table saw will definitely make the KM-1 easier to use when dealing with the rip fence.

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.

Thursday, September 2, 2010

Veneer Tape as Labels

I bought some veneer tape from Lee-Valley awhile back.  Thing is, it comes in ginormous of 650 feet.  Other thing is, it is basically a long postage stamp you can write on!  Here you can see how I've labeled some boards on the rack with veneer tape and a Sharpie.  The tape can be easily removed if you get it damp or with a pass of a scraper.  Certainly more visible and durable than the chalk I used before (like still on the bottom lacewood board).

Now, here I am using it on boards on the storage rack, but it could be useful for labeling parts as it really is just paper stuck to the board so it is clearly readable and doesn't disappear like chalk or stay forever like graphite (in porous woods).

Added thought: if you're a podcaster making woodworking videos, a strip of veneer tape can make joinery marks show up clearly on dark woods :) (Hi, Marc!)

Wednesday, September 1, 2010

Refacing Stairs

Sorry, it's hardly woodworking, but it's what has been happening in my garage lately.  Sometimes trading a fatter pencil for your marking knife while switching into "FHB-mode" is a good thing.  Well, I tell myself that.  As Chris Schwarz said, blog what you know so the next guy can learn from you.  So blame Chris for this entry :)

My neighbor is having me put down high-pressure laminate flooring on his second floor and in his stairs.  The stair 'kit' comes with wider boards that have a built-in bullnose.  They want it put down with no molding on the edges so that 86s the use of a nailer.  Further, the existing stairs have 1" thick particle board with a built-in bullnose.  As you can see, we'll be working with fine exotics.

First step, remove the existing bullnose.  For this, I used the jigsaw and created a guiderail for it.  To do that, I ripped a 5" wide strip of MDF about 34" long (stairs are 36" wide).  I glued a 1" wide strip of MDF to one edge and tacked it in place with a brad (remember, FHB-mode).  Next, run the jigsaw's side-body against the 1" wide strip while cutting the 5" strip.  This leaves you with a guide where the edge is exactly where the blade will cut.  You'll see what it looks like below.

Using a double square, I get the distance from the front of the bullnose to the riser; I want to flush-ish the tread to that riser.

Flip the square and use it to place the guide the same distance from the bullnose.

Screw down the guide; nobody will notice the screw holes.

Now, when I run the jigsaw on the guide, I'll have flushed the tread to the riser.

Now, as a woodworker, you'd think of using a router for this.  a) nobody wants a cloud of particle board dust in their house, b) no matter how careful you are, I guarantee there's a couple nails you'll hit; the jigsaw is more forgiving, c) jigsaw makes chips and minimal heavy dust that settles nearby, d) I happen to use it instead of a miter saw for all the other flooring (because of reason c) so I have just one Systainer to carry :)

At this point, I glued up some of the flooring to make wide enough boards to rip and glue onto the riser.  I tacked them in place with nails near the very top and very bottom since those areas will be hidden.

After the risers are refaced, you can now scribe each new tread to each step; they wanted a minimal gap to the walls (all scribed).  Their wall makes the Great Wall of China look like a straight edge.  Fortunately (?!) it is full-on monsoon season here so those steps are as large as they will ever be.  That said, I'm scribing to within 1/32" of the wall.  You need to wait until the risers are refaced to get accurate tread widths, but less obvious, to get the bevels correct on the sides.

I neglected to take pics of scribing each tread, so some MDF scrapes, flooring offcut, tread offcut and some clamps and voilĂ ! a stair mockup.  The new tread is very small in these pictures as it is an offcut of a real one I already installed (they bought exactly what they needed uhg).  So here goes:

Put the new tread in front of you, bullnose in front, but upside down; we'll be writing on the back.

Using a bevel gauge, measure the bevel of the left side of the existing tread; that is, place the bevel gauge reference against the riser and push the bevel arm against the wall; lock it.
Mark the bevel on the right side of the new tread bottom (remember it will be flipped so left is right; right is left). Here I placed a piece of ply against the bevel gauge then used the ply as a straight edge to draw the line.

Measure the inside measure of the existing tread right above the new riser.  You don't care about the number so push the tape measure against one side and push the body up tight against the other side and lock it.

Transfer that measure by placing the back of the tape on the line you drew on the right and marking the other end; again, you don't care what the number is.  (Yes, I changed the measure for this mock up ;)

Measure the bevel on the right side of the existing step (if you look carefully at the pictures, you'll see that the "walls" flair away from the treads; every step I installed had different bevels!)

Put the bevel gauge on the mark you last made on the new tread and mark the line. You now have the width scribed to the existing step opening.

Last step, measure from the front of the existing step to the back riser on both the left and right side.  Transfer that to the new tread (flipping right/left).  Remember that the front of the step will be behind the bullnose so measure from there.

Alrighty, you can carry all that to your shop 5 doors down and cut them all up.  Here's how I processed them:

I used the MFT because it was convenient, but you could easily lay your guiderail on each line and make the cut.  Since I had the bullnose to contend with, I put a piece of scrap MDF on the tread to be able to lay the guiderail on there.

I did the widths first then moved to the long bench to do the rip off the side.  With the treads on the long bench, I reset the plunge depth to just score 2mm into the tread and ran 3 shallow kerfs.  I want these for the Liquid Nail to grab and hold.

Lastly, a quick pass with the RO-150 in disc sanding mode with P80 to kill the shine on the back.  This was really fast to do and I feel it will give the glue more adhesion.

Now carry it all back :)

Installing the treads.  Well, the dealer said, "use a ton of Liquid Nail for each step".  Sounds like a punt.  I know LN is flexible to a degree.  I want to lock the treads into position, but can't use a nail since the top of the tread is completely visible; no hidden place for a secret nail.  Even a pin nail would show since the laminate face is very chippy on impact.  For the solution, I turned to dowel centers.

I used a 5/16" set of dowel centers.  On the back of each new tread, I made two 1/4" deep holes 5/16" in diameter.  Put them anywhere; I put them in the back third near the outer corners.  Insert the centers in each hole.  Dry fit the tread then press down hard around where the centers are.

The result is a small divot dead center of those dowel centers (i.e., center of your 5/16" hole).  I used this divot to drill a 1/4" diameter hole deep into the tread.

Insert a bit of 1/4" dowel and cut it about 1/4" proud (note that I drill this hole deep so if the dowel sticks up too much, it will just be pushed down).  Also note that the hole in the new tread is 5/16" while I'm using a 1/4" dowel.  This gives just 1/32" play on either side of the dowel and makes insertion so much easier.  Once inserted, the tread never moved laterally.

Once the dry fit verifies you have everything golden, time for Liquid Nail.  I loaded a big bead in the three shallow kerfs, a big bead on the step just behind the riser, a big bead near the back of the step, and whatever goo is on the nozzle into the dowel holes under the new tread (no need to glue the dowels into the steps.

Press down and dance a little on it to squish everything down and release the trapped air (this is why you only want to make beads side to side; if you circle or cross, you trap air).

For this install, I did odd steps one day, even steps the next and had the owners avoid the recently glued steps for a day "just in case".  I found that the dowel pins, though, completely locked the tread in place so I'm happy.

Oh, yes, for the curious, here's a bigger picture of the mockup step :)  Man, the things I do for both of you...