Technique - Matching Existing Compound Angles

When stacking up compound cuts to make an octagonal cylinder or other multi-faceted object, the minor error in each cut also compounds making the last piece fit less than well.

A better method I used for the tapered octagonal column ("tapered octagon" for short!) was to glue up the first seven facets then measure the exact part I needed for the eighth.  Matching the miter angles of the part is easy, but usually there's confusion on how to measure the associated bevel angles.  This short video (no, really! under 7 minutes!) shows how I did the measurement.

I'll also discuss an animation at the end that shows a bit of how the bevel angle relates to the included angle and stock thickness.

No math is used or harmed in this video; safe for all ages :)

(Here's a link to the YouTube page for my email subscribers; sorry I've been forgetting that lately: Technique - Matching Existing Compound Angles)

Over the weekend, I renumbered all the videos (and renamed my local copies to match).  Generally, a new video gets the next number, but videos that are in a series get point numbers.  For example, #82 is the No Comment #2 series so each video is #82.1, #82.2, #82.3 etc to better know the order of the videos.  A viewer on YouTube suggested numbering them all since he found one mid-series by chance and didn't have an easy way to see where he was at. Hopefully this helps, although I understand it can look confusing on, say, the Sculpted Mahogany Vanity build where the last video was #38.12 released after one of the Domino crib-sheet videos #56.  I'm thinking the order in a series is more important than strict chronological order over all of them.  Might be wrong; do that often :)

Bridge City KM-1 Kerfmaker User's Guide

In many of my podcasts, I've used the Bridge City Toolworks KM-1 Kerfmaker to create exactly sized grooves and dados.  It can be shrouded in mystery if you are just looking at the catalog.  Come to think of it, it can be shrouded in mystery when you are reading the "user's manual".

In this video, I'll give you a tour of the KM-1, show how to effectively set the kerf using the actual cutters, and show how to use it in many situations on the tablesaw, router, mitersaw, bandsaw, and even the Bridge City JMP Jointmaker Pro.  There'll be a number of demonstrations with close-ups to unveil the shroud!

The KM-1 is part of Bridge City's "Essentials".  While many commemorative tools are made only once never to be made again, the KM-1 is generally always available.

If there's one thing I could say to convince you of its utility, it would be this:

I've only used my dado stack in two sizes: 1/4" and 1/2"; the shims are still shrink-wrapped

(I've always wanted to use the word 'shrouded' in a blog posting; hurrah!)

EDIT: at the time I posted this, Bridge City was regrettably out of the KM-1s.  I just got confirmation from Bridge City that they will be back in stock in 6-8 weeks.  That puts them as available around the last week of July 2011/early August.  Put yourself on the list to get one when they are available.  Worth the wait.  I waited much longer as I got in on the first run!

Sculpted Mahogany Vanity - Stock Preparation and Top Segment

And we're off!  In this episode, we'll sort through the rough stock (ahem, in my neighborhood, 'rough' stock is regrettably S2S) then use a Festool TS-75 to straight-line the boards before using the table saw for the parallel cut.  The upper segment of the vanity's structural insides will be Dominoed (I love how in English you can verb anything).  We'll talk about a couple different Domino techniques that come up in this segment.

The underside of this top segment is in three sections.  The two outer sections will have drawers so we'll make part of the structure into drawer runners and resaw some Mahogany for two panels on the underside. You'll see a quickie tour of the KM-1 being used to exactly size the panel groove.  I'll be doing a video user's guide to the KM-1 soon.

While not on the video, the next step is to sand or scrape the panels and put finish on them before gluing up the upper segment.

In the next episode, we'll make the lower segment, the drawer webbing, and glue up the panels that will wrap this wireframe structure.  Then we'll get in touch with our inner-Rodin and sculpt! ...but hopefully it won't look like the Gates of Hell.   :)

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.

French Knot Walnut Inlay in Cork Floor

I took several pictures while doing this project because the Festool "system" surrounding the OF-1400 router was key to its success (yes, yes, you could make your own rail or do it by hand, but this was fast, easy, and, uhm, smart :)  I also posted this entry in a shorter form on FestoolOwnersGroup.com as part of a contest I won't win.

Here, I have my new entryway :)  I took 2 sheets of 1/8" luan plywood and cross-laminated them together to form a substrate that was water resistant and able to be directly attached to my slab foundation.  I covered it in a nice cork in a herringbone pattern; in dry-fitting the layout, I found the herringbone pattern didn't telegraph the seams as much as others.  I then laid out a French knot pattern with masking tape that by chance was very nearly the same width as my extremely bowed scrap of Walnut :)  Center stage is the OF-1400 router and a guide rail.  Those two made this process ridiculously easy.

To route the recesses in the cork, I'm using a 1/4" down-spiral bit.  My process is to route away the outside edges of the recesses then go back and eliminate the part left behind with another bit.  I just don't want to buy another bit to avoid the 10-minute pass with another bit to finish it off.

To make sizing the recess dead-nuts accurate, I'm going to use the KM-1 by Bridge City Toolworks.  The KM-1 works by using the size of your cutter (a router bit in this case) and the size of the dado (recess here) to create 2 offset fences that you'll see as I go along.

Set the 'orange' jaw of the KM-1 to the width of the bit your using.

Next, set the grey jaws of the KM-1 to the width of the walnut we're inlaying.  Keep it close by :)

Okay, this picture has several important points.  I swapped the stock base with the table widener.  In this case, I don't need the added stability the widener gives the OF-1400, but rather the added thickness that lets me use the guide stops off the back of the rail so the router is sitting on the stock instead of on the rail (I generally don't like it sitting on the rail since I never get the compensating support foot to lock solidly).  Note how I do not have the micro-adjusting screw of the guide stops attached between the stops.

Position the bit so it will cut the inside edge of the recess (inside meaning closest to the guide rail).

 I do use the dust guard, but find that I had much better visibility if I left the front part of the guard open.  It didn't change the dust collection much.  Remember that this is a down-spiral bit so most of the waste was left in the wake of the recess.

Measure from the guide rail to the inside edge of the recess as you'll use this to properly align the guide rail to the recess for all future cuts after the initial setup is completed.  Note that using a triangular bench rule like this one is nice since it butts up to the guide rail eliminating some error.

At this point, the router is ready to route the inside part of the recess, but we want this to be as "faster, easier, smarter" as can be so we need stop blocks calibrated with the KM-1.

In this picture, the leftmost guide block is first locked in place.  The KM-1 is placed between the guide blocks in the "long" position and the rightmost guide block is moved to touch it and locked into position.  The rightmost guide block will never be moved again in this project.  You'll notice something to the left of the leftmost guide block (apologize that it wasn't in the previous pictures).  That is the microadjuster for the MFK-700 as it fits perfectly on the rods and locks.  I use it as a well-sized stop block.  Butt it up against the left guide block and lock it in place.  You won't move it again.  Note that the "microadjust" ability is not used; it just sits there like a dumb brick marking a stop location; I plan on ordering another by digging through the Festool EKAT parts system.

Next, flip the KM-1 to use the "short" fence.  Loosen the leftmost guide block and move the router over until the KM-1's short fence is between the guide blocks.  I have a stop collar from a drill-bit set to the right of the leftmost guide block (right behind the KM-1... it's small).  It doesn't fit as well as I'd like, but worked.  Tighten this stop collar to mark the short fence location.  You can return your KM-1 to its hand-made walnut keeper chest now; the collars will mark our offsets.

This is where your router bit should be located right now after the adjustments using the KM-1 (if not, verify you didn't budge the guide rail).  Also remember that in my case, the tape is nearly identical width to my walnut; YMMV.

So now you are ready to crank through the routing operations.  Note in the original picture that several recesses line up within a French knot and to an adjoining French knot.  This is by design.  Even if your tape isn't perfectly laid out, using the guide rail aligned across all co-linear segments will make the whole that much better looking.

Here's the steps:

1. Place the guide rail the distance noted above from the inside edge of a recess to route.  Clamp the rail because patching this cork is not an option.
2. Loosen the leftmost guide block (one between stop collars) and slide the router until the guide block abuts against either stop collar.
3. Plunge and route; I usually scribbled with a red Sharpie at the ends of a segment so I could be forewarned when looking through the router window.  Stop early as it is easy to square the corner with a sharp chisel.
4. Loosen the leftmost guide block again and slide the router until the guide block abuts against the other stop collar.
5. Plunge and route.
6. Go to step 1 until you have no more recesses.  This is a very fast cycle.

Once the recesses are done, chuck up a straight bit (1/2" in my case) and freehand between the "moats" you just made to clear the waste between the edges.  This won't be neat.

Occasionally the rail didn't make it the whole way across the board.  It missed by inches.  For that, I inserted the rail connector into the rail and put a small piece of home-sawed veneer under the connector before clamping it down (veneer simply takes up the space under the connector so it doesn't pop the rail up).


Next up, cutting the walnut to length and mitered corners.  This isn't difficult, just tedious.  One tip: when 7 segments go in first-try and the eighth is being, uhm, fussy, check for new posts on your favorite forum.  Really, you just need to walk for a second.

So the rest of this has less to do with the router, but finishes the story of the floor.

Here's the walnut dry-fitted into the recesses.  You want a very snug fit, but try not to fully seat anything while dry-fitting since pulling it out can shred edges of the cork (this is why an up-spiral bit isn't appropriate).

 Paint the recesses with contact cement and let it flash off (about 30 minutes).

Paint the back of each inlay piece as well.  Note that I labeled each piece on the back to know where it goes.  Put pieces in order into the recesses.  I found that gently pushing them in and aligning the neighbors was the best way before pressing down hard.  Once you press down hard, it's done.  You'll want a scrap of cork glued to a block so you can use it to mallet the inlay pieces afterward to ensure they are seated and glued.

I used a shoulder plane to flush the walnut to the cork.  I preferred the medium shoulder plane mostly because the blade was just marginally wider than the walnut.  This greatly reduced the chances of striking the cork.




Voilà, the finished inlay!

For context, it will be in the entryway at the bottom of a set of stairs I refaced almost 2 years ago.  Here are some photos.

Bottom step will have the riser attached after the entryway is installed over the tiles you see to the right in the photo.

The landing has a French knot, as well.  It was done in a much more difficult manner; I was more stupid back then.  Oh, the lopped off corner of the entryway inlay is where the door is for the entryway so the entryway and landing will look the same from the top of the steps.  I have since installed base molding.

The bullnose of the existing treads was cut off and replaced with triple-beaded walnut.  Risers are home resawn lacewood veneer.  The corner molding you see here was custom cut and has continuous grain from the topmost step to the bottom.  Now, that molding is trivial, back then, it was tricky.  Guess I learned something :)

Digital Angle (Tilt) Gauges

I always thought those digital angle tilt gauges were cute, but not something I needed. Was I wrong.

Recently, Wixey angle gauges were on sale and I snagged one thinking it would be great to use to calibrate my SawStop that was arriving the next week. Silly... who needs it calibrated when you can simply slap the tilt gauge on the table, zero it, then put it on the blade while you set the bevel.

While playing with it, I used it to set my bandsaw blade to 90* and set the set-screw of the table so I could return it conveniently. Well, the set-screw seems to move when the saw starts up so forget it; use the simple gauge each time for accuracy to +/-0.1*.

Here's the short list of the things I used it on in the first week, and the list will grow:

• Setting the drill press table to 90* to the drill (use a long 1/2" bit for this); remember to do it in side-to-side and front-to-back directions.
• As a digital level; I stuck it to a 4' spirit level set level then zeroed it. Now I can put the gauge on anything and treat it as a digital level (only as accurate as the spirit level, but in this case, the digital level is only 1.5" long!)
• As a digital winding stick; I put a level across the front of a board with the gauge on it and zeroed it. As I slid the level back, I watched the gauge to see how level the board was. I could certainly see myself using it for rails for a router in the same way. Note that I used the level because it has a flat base; you could stick it to anything.
• Clamping up a cabinet; I happen to be making a hanging cabinet for the shop (stupid projects over summer cuz it is just too hot to be serious!). The base of the cabinet sat on the assembly table that is flat. Zero the gauge there. Now, when I put parallel clamps on the sides of the case, I pushed them up until the bar touched the cabinet on top and bottom. Now, stick the gauge on the side of the bar to ensure it is 90* to the assembly table. Perhaps a silly use, but I thought it had promise.
• As already mentioned, setting the bandsaw table to 90* to the blade; also used it for two other odd-angle cuts for a ramp and for glue blocks.
• Oh, yeah, setting the bevel angle of the table saw blade. :)

Other uses I can see in the future:

• I need to put in a concrete pad on the side of the house. It needs to dip away 5* from the house to keep from accumulating water. Set the concrete form by the house and set it level with a level. Now set the form for the other side and set its height with a straight beam going from the first form to the new form; use the gauge on the beam to set a 5* drop consistently. For a guy like me who doesn't do concrete very often, this will be useful.

Now, I did see a gauge I believe in Woodcraft's catalog that allows you to hit the zero button twice in a row to make the gauge zero to true level. That would be worth the extra $2.