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Comments Off on Making a Magnetic Bottle Cap Opener

Let’s start with the easy stuff, sourcing the wood and cap opener.  If you’re reading this you’re likely a woodworker and if you’re a woodworker you likely have some scrap wood lying around so your wood may be free for this project.  Something around 3″-4″ wide by 8″-10″ tall should work fine, 3/4″ thickness or more is recommended.  For the opener itself thousands exist.  A quick search on the internet for “wall mounted bottle opener” will give you more options than you can shake a stick at.

Lots of choices…

Now for the magnets.  I’ve made a few of these openers now and I’m pretty comfortable saying you’ll want to use 1/2″ diameter rare earth disc magnets.  They should be 1/8″ – 1/4″ thick depending how many you use, but I’ve found 4-6 total does the trick.  With all that out of the way, here’s the process I’ve used.

Begin by sizing and shaping your board as you see fit.  This can take 5 minutes or 55 minutes depending what kind of detail you want to go into, but in short make your board flat on two faces, dress up the edges, and move on.

This opener was for a client. He ordered the opener, I selected the cherry with a live edge.

I cleaned up the live edge with a spokeshave. This leaves some of the surface variation intact. I could have used a hand plane, but that would have made the edge perfectly uniform, something I wanted to avoid on this particular edge.

After cleaning up the board, I decided to mimic the live edge detail on the other side.

I removed the bulk of the material with heavy cuts from my jack plane, then finished with a block plane.

The top and bottom edges received a simple 1/4″ chamfer…

…and were cleaned up with a block plane.

Once the board is brought to size and shape the various holes to be drilled can be laid out.  I start by positioning the opener where I want it and mark the screw holes.  I also mark what portion of the board will be covered by the opener when it’s mounted.  Pre-drill the screw holes for the opener, then look at the available space in the “will be covered” portion of the board.  Drill and countersink/counterbore a hole in the area large enough for a screw that can be used to mount the board.  Since it will never be seen I used a basic drywall screw.

With the opener in position, mark the location of the mounting holes.

On the back of the board, layout your magnet array.  I’d go with two rows of three magnets or a triangle layout with three magnets at the bottom, then two above that, then one above that.  You can test various configurations on scrap wood until you’re satisfied, then break the scrap wood apart to retrieve the magnets.  The drilling process is crucial for these boards since the strength of the magnets decreases exponentially as the distance from the magnets to the bottle cap increases.  To get the magnet as close to the surface as possible, two bits will be used as described below.  You can also read more about magnet selection and installation from this Rare Earth Magnet Article.

First use a standard brad point bit to drill a hole the same diameter as the magnets you are using.  Set the depth stop on your drill press so the tip of the bit stops about 1/16″ from the front face of the board.  I use shim stock to locate the bit.  Drill all your holes, then replace the brad point bit with a sacrificial bit that has had its tip ground flat.  This can be a twist bit or forstner bit, but it must be ground flat.  Set the depth of this flat bit to the same 1/16″ depth and re-drill the holes.  This will clean out the bottom of the original hole and leave a flat base.  Now drop the magnets into the holes and plug the back of the hole with a dowel.  Be careful not to pound the dowel in.  You left 1/16″ or less of material in front of the magnet and driving the dowel home will split the wood and force the magnet through the surface of the board.

Drill all the holes with the brad point bit, then reset the depth and re-drill the holes with the flat bit.

The board is just about ready for mounting at this point, all that remains is adding a nail to the back of the board to prevent it from rotating around the mounting screw (which is hidden behind the metal opener).  I just pick anywhere towards the bottom of the board between the magnets, and pre-drill a small hole.  Before tapping in the nail, apply your finish of choice.  I typically use some whipe-on poly to build a thin finish and provide a little scratch protection from the bottle caps.  Once the finish is dry, tap in a nail then cut the head off and file it to a point.

Anti-rotation nail installed, head cut off, shank filed to a point.

The board is now complete, but there is a bit of an installation process to follow.  The opener must be removed and the mounting screw taken out.  Figure out where the nail should go, drill a small hole and press the nail in.  Align the board and mark where the mounting screw will go.  Take the board off, pre-drill the hole for the screw, then put the board back again.  Install the mounting screw, then the opener.  I use a screwdriver here, not a drill, to avoid slipping off the screw head and damaging the board.

Pre-drill a hole for the nail. Install the board. Mark where the mounting screw goes. Remove the board. Pre-drill for the mounting screw. Install the board. Add the mounting screw. Add the opener with a screwdriver, not a drill. Done.

There are lots of ways the board could be mounted, I use this method so the end result looks as clean and simple as possible.  Anyway, have fun with it and when you’re done you can enjoy a frosty beverage as a reward for you efforts (which will taste better when drank out of this).

Board up…

…and ready…

for action.

-WMT

 

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Comments Off on Dovetail Joinery: Part 6- Fitting and Finishing the Joint

Coming down the home stretch now (finally).  The pins should be cut, the waste removed, and the baseline chiseled square as discussed in Part 5.  You probably have something that looks like this…

Test fitting the joint

But will it assemble?  Maybe, it depends how good you are with a dovetail saw and if your pin board is a softwood or hardwood.  Softwoods are much more forgiving of a slight interference fit.  Try to assemble the joint dry, just enough to get a feel for if the joint is too loose (gaps), too tight (get out your chisel), or just right (time to glue it up).  The biggest risk here is if there is too much pressure on the outside pins.  There is no wood supporting them and they can easily split at their base if the outer tails are too large, wedging the pins apart.  This is why we size the outside pins a bit thicker than the rest, to add some strength and lower the risk of a split.  So, if the joint slides together with almost no hand pressure you likely removed too much material with the saw and will be faced with gaps.  Minor gaps can be addressed in a variety of ways.  Some people use generic wood filler, some mix glue with saw dust from the wood being used in the joint for a better color match, you can also try to glue in some wedges of the same wood if the gap is large enough… though if it’s really bad you should probably just start over.  It’s all part of the learning process, but after even a few test joints you should be getting respectable results.

My first dovetail from 2008, not pretty. The one above it was just a few joints later.

Lets assume you don’t have gaps, but you don’t have a perfect saw-cut-to-saw-cut fit either.  This is when a little chisel work may be required, but that’s not a big deal.  Chiseling the sides of the pins (an operation known as “pairing”) is a lot easier than working on the tails because we have plenty of open room to work with.  Never try to go back and tweak the tails at this point.  Trying to identify where the excess wood is located can be a little tricky.  Look for your knife line from transferring the tails over.  If you didn’t split it there’s a good chance the knife line is still visible and the pin is fat in that area.  Also look for pins that weren’t cut vertically.  If the saw drifted away form vertical the pin will get fatter as it approaches the baseline.  This means the tail may slide on nicely at first and then bind up when it’s part way home, never fully seating itself.  If everything looks good but the joint is still a little difficult to assemble look for burnished areas at the top of the pins or any other signs that there is high pressure on certain areas that resulted from test fitting the top 1/8″ or so of the joint.  What you want is a joint that can go together with hand pressure or light hammer taps.  This is again something you will get a feel for after fitting a few of these joints together.

The side of this pin needs a little work.  You can see the knife line wasn’t quite split by the saw and the saw drifts away from the vertical line.  Proper sawing can save a lot of extra chisel work at this stage. Mark off any areas that need adjustment…

…then go to work. Be careful not to push a deep cut through the back of the pin or you will blow out the wood fibers on the back edge.

Once you’ve got the desired fit the joint is ready for gluing.  I like to add a partial chamfer on the back of the tails as pictured (something I picked up from the Rob Cosman dovetail DVDs).  This does a few things.  If I have several joints in the works, the chamfer tells me “this one is done” and helps avoid confusion.  It also eases the tails over the pins which helps avoid damage to the tops of the pins.  Finally, it gives a little extra area for the glue to go and minimizes the squeeze out.  Just be sure the chamfer is on the inside of the joint (where it will never be visible) and it doesn’t extend to the top of the tail.

Partial tail chamfers on the inside of the joint.

Now add glue and clamp up the joint.  I like to use small spatulas for working glue between the tails.

Glue the sides of the pins and tails, I don’t worry much about the baseline because it’s all end grain.

When the glue dries, the joint may look a little messy from the glue, pencil marks, and not-perfectly-flush surfaces.  Plane the surfaces flush, removing any glue spots or other surface defects in the process.  Be sure to plane away from the joint so you don’t blow out the end grain of the mating board.  That’s a mistake you’re only going to make once.  If this were a drawer you were making, this would be the time to plane the sides down to achieve a perfect fit to the case.

The joint after gluing. Throw it in a vise and flush up the faces.

Below is the joint after its been cleaned up.  I did no filling or “cheating” of any kind.  The tail board is straight off the saw, no chiseling at all (other than chopping the baseline of course).  The tail board is mostly off the saw, but a few of the sides needed some minor adjustments as discussed previously.

Cleaned up joint, ready for finish.

The end result with a basic oil finish.

After gluing, cleaning up, and finishing the joint, it’s finally done.  One thing worth discussing at this point is the baseline which is obviously still visible below the tails and pins.  Is that normal?  It looks ugly. Does it serve a purpose?

Visible baseline on the finished joint. To keep it or remove it?

Well, the baseline knife mark is there because we made the joint by hand and a lot of people like to leave it visible for that reason alone.  Another sign (along with skinny pins) that this joint was not machine made.  That’s fine.  Other reasons to leave it there is because it takes more work to exclude it than include it.  If the joint isn’t going to be seen often (the back corners of a drawer or a case joint that will have molding covering it) than leaving it is just more efficient.  If you’re making a box or something where it will be visible then it becomes a question of appearance and largely boils down to personal preference.  If you don’t want to see the baseline in the end, there are two common approaches I take.  First, I won’t cut the baseline so deep with my marking gauge, then when I’m done I just plane off enough material to remove the scratch.  The other option requires a little more planning.  You need to lay out the joint first and then only mark the baseline on the areas that will eventually be removed.  So you basically end up with a dotted line instead of a solid baseline.  Anyway, there’s no right or wrong here.  It’s your joint, make it how you want to.

And that takes care of that.

-WMT

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Comments Off on Dovetail Joinery: Part 5- Tail Transfer and Pin Creation

If you have been following along in parts one through four, you should have your tail board finished and your pin board dimensioned.  The next step is to transfer the tail locations to the pin board by using the tail board as a template.  This is why you don’t need to precisely follow the angle you laid out when sawing your tails, any slight deviation from the pencil line will be transferred to the pin board and copied exactly.  Missing your slope is purely cosmetic and the joint can still go together seamlessly.  To transfer the tails, align the pin board so it’s even with the side of a bench plane or block of wood as pictured below, then clamp it in the vise.  Slide the plane/wood back and use the tail board to bridge the gap.  Now the shallow rabbet that was created in part 1 becomes extremely useful.  Slide the tail board up to the pin board until the small shoulder from the rabbet hits the pin board.  You should immediately feel the rabbet’s shoulder align the board.  This accurately solves two of the three alignment problems you can encounter in this step: 1) skewing or rotating the tail board relative to the pin board and 2) sliding the tail board too far forward or not far enough.  All you need to do now is slide the tail board side to side until the edges are aligned.  A block of wood can help.

Clamp the pin board so its top edge is flush with a plane or block of wood. Slide the plane/wood back and use the tail board to bridge the gap.  The rabbet from Part 1 aligns the tail board.  Scrap wood or another flat object helps align the edges.

Now use your off hand to press in the middle of the tail board, locking it in place.  Use your dominant hand to hold a marking knife and scribe the tail locations into the pin board.  I’m using the thin kerf knife from Blue Spruce Toolworks as it can fit between any tails I cut.  For larger work I typically use a larger knife.  Press the knife firmly against the tail with the flat face touching the tail.  If the beveled face of the knife is against the tail the knife line will be offset and your pins will be far too thick.  Draw the knife along the tail with light pressure, but repeat this a few times until a clear line is visible.  Again, be sure to keep firm pressure on the side of the tail so the knife doesn’t stray.

Transferring the tails to the pin board.

Once the tails are transferred, mark the waste (the tails obviously, we want to keep the wood that will go between the tails which are called the pins) and using a marking gauge, scribe the baseline as was done in Part 1, but this time only mark the faces.  The edges will not be cut off so there is no need to carry the baseline all the way around the board.  Be sure to reset the gauge to the thickness of the tail board as it is typically not the same as the thickness of the pin board.  Having a dedicated gauge for each measurement is helpful when several joints need to be cut.

Measure the thickness of the tail board and scribe the baseline of the pin board.

Now clamp the board in the vise for sawing, being sure to align it vertically first.  If it’s clamped at a slight angle you will have a hard time hitting your vertical lines right off the saw.

Align the pin board vertically

Now use a square or dovetail guide to mark vertical lines, these will help guide your saw.  I like to draw them in the “good wood” portion of the board so they aren’t sawn off.  Then when the joint is cut I can see how parallel my cut was to the vertical line.  This will give me an indication of any clean up work I’ll need to do with a chisel.

Ready for sawing

Now to saw the pins.  The same sawing techniques apply that were discussed in part 3, but you aren’t sawing square across the board this time, you are trying to split the knife line.  This means with saw cutting on the waste side of the line, the edge of the kerf should land right on the center of the knife line.  The cut must then go straight down, parallel to the vertical lines that were just drawn.

Splitting the knife line. It’s a little hard to see, but the back of the board shows the saw kerf beginning to form, the front of the board is what remains from the knife line. Notice how the edge of the kerf runs through the center of the knife line.

A perfect cut. Splitting the knife line, vertical, and stopped just at the baseline.

With the sides cut, saw out the waste with a fret or coping saw, then chisel the baseline exactly as was discussed in part 4.  Be sure to check that the baseline is square and without humps that could prevent the tail board from seating fully when assembled.

Waste removed

For the next (and likely final) part of this series we’ll be fitting the pins to the tails, gluing the joint, and cleaning it up.  Until then, happy joinerying.

-WMT

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Comments Off on Dovetail Joinery: Part 4- Chisel Work

Part 3 of this series wrapped up the saw work for the tail board.  Now there’s just a little chisel work to take care of before moving onto the pin board.  For smaller work, I like to lay the parts on my shooting board.  This gives me something to back the work against and also provides a sacrificial surface that can be gouged with a chisel on occasion.  Make sure the board is clear of debris before you start working or you may press something into the face of your board, denting it.  This is quite aggravating if you’re working on a drawer face or the outside of a box.  I can say “quite aggravating” now because I’m typing, but if this happens in the shop and potentially ruins an otherwise flawless piece of work… well, my grammar may be quite different.  The real issue here is at first the work surface may be clean, but as you start chiseling out the waste those bits of wood fall on the bench or shooting board.  Then without thinking, you flip the board over and start chiseling from the other side and one of those stray wood fragments gets embedded in your board.  So every time you move or flip the board, make a habit of clearing the debris.

A simple chisel set up

When chiseling to the baseline, there’s a few things to keep in mind.  First of all, unless you’re really good with your fret or coping saw, you probably have a decent amount of waste to clear… maybe 1/16″ – 1/8″ of material for most people.  Typical advice is to remove half the waste at a time until there is such a small amount left that you can’t split it, then drop the chisel in the baseline and finish it off.  That’s actually a good method to use.  Chopping through too much waste at once drives this chisel back into the board, crushing wood fibers behind the chisel in the process.  If you drop right into the baseline and the chisel is driven back, you’ve just crushed good wood and you’ll be looking at an unsightly gap when the joint is assembled.  So don’t get greedy, take the 2-4 chops you may need to take and work your way back to the baseline.  Another important tip if you’ve never considered this is which way to pry the chisel.  If the chisel gets stuck in the board you need to pry it loose.  Not a big deal, but you need to push it away from the baseline.  Prying back against the baseline will again crush the wood fibers and carry the chisel across the baseline.

The chisel on the left is prying itself loose by pulling against the baseline… this is bad. The chisel in the middle picture is pushing away from the baseline… this is good. You can see on the right how the chisel crossed the baseline.

As to the chopping process itself, I stand on the side of the board hold the chisel vertically (basically what is pictured above).  If you’re positioned in front of the board you can’t tell if the chisel is vertical or not.  If you have to, undercutting the joint is perfectly acceptable 90% of the time or better, at least in my opinion.  Chop about half way through the board, then flip it over and chop the remainder in from the other side.  This avoids blowing out fibers which is almost a given if you chop entirely through the joint.

The last bit of chopping, dropping the chisel right into the baseline.

Once the waste is chiseled out between the tails, clamp the board back in the vise and clean up the outside shoulders, then check everything for squareness.

Clean up the shoulder

When checking for square, the smaller the tool the better.  My square is a vintage Millers Falls model, but Starrett and Vesper Tools also offer nice squares similar to what’s shown.  Check your shoulders, baseline, and the cheeks of the tails.  Any humps in the baseline should be removed, with an undercut if need be.  The tails should never need squaring if you’re sawing correctly… but if they are out of square you have to fix it now or you’ll never have a tight joint.  If you can’t get a chisel between the tails to fix a skewed cheek you may be out of luck and need to start again.  The joint can still go together obviously, but you’ll be filling gaps for sure.  Again, with a little practice at sawing you should never need to adjust the tail cheeks, just the baseline.

A square shoulder is your friend.

If the square can’t touch the baseline at both sides there’s a hump.  Remove some more material.

Check the cheeks. With a little practice these should always be square, right off the saw.

Next up we’ll be tackling the pin board.

-WMT

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Comments Off on Dovetail Joinery: Part 3- Sawing the Tails

Accurate sawing starts with accurate layout which was covered in part 2, but there are several other factors that should be considered from body position to how the saw is held and more.  For solid information on basic sawing techniques (and a whole lot more) I’d recommend The Foundations of Better Woodworking by Jeff Miller.  What I will say here is that a moxon vise and properly tuned saw will make a world of difference.

Moxon sawing set up

A moxon vise raises the work to a more comfortable sawing height (your back will thank you).  My moxon was made with the kit from Benchcrafted, but you can also get a more affordable kit from Texas Heritage.  Your saw should be sharp, filed with a rip tooth pattern and a fairly high tooth-per-inch count, 15 is common.  The set on the teeth also needs to be minimal, a couple thousandths on either side of the plate to ensure straight sawing.  And when you clamp the board in the vise, align it vertically.  If the board is tilted slightly hitting angles or sawing vertically becomes unnecessarily complicated.

Align the board vertically with a square.

Sawing on the bench vise (left) vs the moxon vise (right).

Now lets get into it.  When you start sawing across the end grain, sawing square to the front face is absolutely critical.  A skewed cut will never yield a tight joint so you will either have gaps or have to do extra chisel work to square up the cut after sawing.  This is okay, but chiseling takes extra time and adds another opportunity to make mistakes.  What we’re shooting for here is saw-cut-to-saw-cut joinery.  So how do you saw squarely to the face?  Place the saw on the waste side of the layout line and lift the saw slightly.  This means the saw teeth are only touching the far edge of the board and the saw can pivot around that point.  Next, place the thumb from your off hand next to the saw plate and bias the saw plate against it.  Using your thumb to steer the saw, align the teeth so they’re parallel to the layout line and start sawing with very light pressure.  As the saw starts to cut into the board, lower the handle so you’re sawing straight across the board.

To begin the cut, raise the saw (exaggerated for clarity), then use your thumb to steer the saw.

At this point the saw shouldn’t be very deep, just a light kerf cut squarely across the end grain.  With this kerf established, focus on angling the saw to match the layout line and begin taking full, even strokes with the saw, not short, choppy cuts.  I have found this to be an important part of saw-cut-to-saw-cut joinery.  Full, smooth strokes means the cut can be finished in a few strokes, 4-8 is typical for most of my dovetails.  This helps ensure a straight cut which is crucial.  Short saw strokes means you may need 15-20 strokes to finish the cut… each time the saw may stray slightly.  The kerf can also become enlarged which makes tracking the saw more difficult, so practice your sawing until you can fly through a cut smoothly and with confidence.  A good way to practice sawing or just warm up for dovetailing is to run through several cuts on scrap wood.

Practice sawing. If you can’t do it on scrap wood how will you pull it off on the real deal?

Once you’re comfortable sawing to your line and squarely across the board, cut the sides of all the tails.  I recommend cutting one angle first across the entire board, then go back and hit the other angle.  This helps keep your muscle memory on track where as switching between angles can make it hard to get in a rhythm.

Saw one angle, then go back and saw the other.

Before moving on, lets examine the cuts and understand what’s critical.  We’ve already talked about cutting squarely across the board, but what about hitting the angle precisely?  Well, having a straight cut matters, having that cut run to the exact angle laid out with the dovetail guide doesn’t really matter, it’s just for looks.  In fact, you could cut the joint with no layout lines at all on the face, just cut squarely across the board and the angle can be whatever it wants.  The reason to lay out an angled guide line is just to help keep the tails as consistent as possible, but it’s purely for appearance sake.  For the joint to fit tightly you only need to saw squarely and in a straight line.  Skewed cuts or wavy cuts will always result in gaps.  The only other sin to avoid when sawing is cutting beyond your baseline.  There’s really no fix for that besides wood filler.

In the top photo, the left cut was made squarely, the cut to the right is skewed and will result in a gap.  In the bottom photo, the left cut is parallel to the layout line and stops at the baseline.  The cut on the right is not parallel, though this is only an appearance issue, the joint can still close nicely.  The bigger issue with the cut on the right is that it extends beyond the baseline.

Saw out the waste with a fret or coping saw (I opt for a fret saw) being careful not to cut below the baseline or into the tail itself.

I bent my saw frame so it clears the board no matter what the length. Learning to saw close to the baseline will save time with the chisel, but be careful not to go below the baseline.

The last step before moving onto the chisel work is to cut the waste off the edges.  Flip the board 90 degrees (making sure to align it vertically again) and grab a crosscut saw if you have one.  You’re sawing right against the baseline, so make sure to stay on the waste side of the line.  One thing that can help is chiseling a small shoulder up to the baseline.  This little valley gives the saw an accurate “kerf” to start the cut and leaves a super clean shoulder on the joint which will be visible when all is said and done.

Chiseling a small shoulder to help guide the saw

Flip the board and cut the other shoulder, then it’s time to get out a chisel to clean up the baseline.

-WMT

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Comments Off on Dovetail Joinery: Part 2- Laying Out the Joint

With the boards prepped as discussed in part 1, it’s time to lay out the tails for sawing.  To do this, you will need two sets of dividers (also referred to as a compass, but I don’t want to get into that right now).  I own four Starrett sets which covers just about anything I’ve ever done.  The tips should be ground to a point and I prefer to have them all in different sizes so I don’t confuse which pair has which setting.

No repeat sizes helps avoid confusion

Use one set of dividers to mark the side pins.  These tend to be a little thicker so they don’t split, I’m using 1/4″ here.  Mark that distance in from each edge of the board, then set that pair of dividers aside to use on the following joints in the other corners.

Mark in from each edge

The second set of dividers will walk off the number and width of the tails and consequently the pin space between each tail, all without the fuss of measuring.  To do this, guesstimate the size of the tail, set the tip of the divider into the pin hole (on the left in this example) made by the first set of dividers and step it across the board until it passes the far pin hole (on the right side).  Each step will be a tail, so if you want three tails, you need to take three steps, four tails, four steps, and so on.  Be careful to walk the dividers lightly across the board.  You don’t want to create any pin holes until you’ve finalized the setting on the dividers.

Starting in the pin hole on the left, walk the dividers until they pass the pin hole on the right.

The distance the dividers overshoot the pin hole on the right will be the gap between each tail.  Don’t actually create a pin hole here, just gauge the gap by eye and decide if it needs to be thinner or thicker.

The distance the dividers overshoot the pin hole will be the gap between each tail.

Adjust the dividers and repeat the process until you have the correct number of tails and are satisfied with the gap size.  Now you can step the dividers off one last time, this time pressing hard enough to mark the board.  When the dividers cross the pin hole on the right, stop.  Do not mark a pin hole here.  Instead, shift the dividers over so the leg falls into the right side pin hole, then step the dividers back to the left.  Now you’ve got a board with pin holes in the end… so what?  So now we pull out our trusty friend, the dovetail marking guide.  There are a variety to choose from, I wrote about some here.

All kinds of angle options

Place a pencil in the pin hole on the far left, slide the guide over until it hits the pencil, then mark both the face and end of the board.  I stop the pencil line on the face of the board at the baseline of the joint.  This helps avoid sawing too far which we’ll discuss in the next blog entry.  Sliding the guide to the right, mark every other hole, then repeat the process from the other direction using the opposite slope.

Drop the pencil in the pin hole, then slide the guide to it.

Mark both the face and end of the board before moving the guide.  Note that the face line ends at the baseline.

When the layout is complete, mark the waste areas so you don’t get confused…

Finished layout

…and get ready to start sawing.

-WMT

 

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Comments Off on Dovetail Joinery: Part 1- Tools and Prep

Fitting supremely gloat-worthy dovetails starts with having the right tools and proper board preparation.

Tools for hand cut dovetails

Each of these tools will be discussed as they are used in the process, but the first step is board prep.

I’m making a sample joint so I have two relatively small boards.  If you’re making a drawer, box, or casework of some sort you’re typically going to have four sides and four corner joints to deal with.  Begin by planing each board to the desired thickness with parallel edges.  If you’re using a powered planer, make sure to at least plane off the machine marks before starting the joint.  The ends are critical and must be square to the face and edge of the board.  This probably means you can’t just cut your board to length on a chop saw and call it “good enough”.  I always square up the ends on a shooting board before dovetailing.

Smooth the faces

Shoot the ends

End square to the face

End square to the edge

For clarification, I’m using cherry as the tail board (which I cut first) and the poplar will be the pin board.

Tail and Pin boards

I don’t care if you prefer the tails-first or pins-first method, whatever gets you the best results.  I go tails first for three reasons listed in order of their significance:

1) It’s how I learned to do it. 2) I think it’s easier to cut the pin angle by skewing the saw to the face of the board and cutting straight down, but I’ll go into more detail on this when I get to cutting the joint itself. 3) I can gang-cut two tail boards at once which saves time.

Before actually laying out the tails there is one more step, cutting a small shoulder on the tail board.  First, use your marking gauge to scribe the baseline of the joint.  Measure the thickness of the pin board, then run the line around the entire tail board.

Set the thickness of the pin board…

…and transfer that setting to the tail board.

Carry the line around the entire board.

Now add the shoulder on the inside face of the tail board.  This is often known as the “140 trick” because you can use a #140 block plane to cut the shoulder.  For larger work I use a rabbet plane, but for narrow boards like this I’ve become fond of using a router plane.  Check out my blog post covering this technique here.

Using a router plane for the 140 trick. I may need to rename that trick.

The completed shoulder. Somewhere around 1/64″ should do the job.

The point of adding this shoulder will become clear when we transfer the tail locations to the pin board.  For now just add it to the inside face of the tail board and you’re ready for laying out the dovetails which will be the focus of the next blog entry… stay tuned.

-WMT

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In:In the Shop

Comments Off on A Modified Marking Gauge

I had this idea pop into my head the other week and decided it wasn’t going to stop nagging me until I tried it.  So here’s what went down and where it’s headed next.

When sawing to a line, there’s a few typical steps and hand tool individual would take.  First, use a marking gauge to scribe a line parallel to an edge.  This creates a crisp target to work to, but trying to drop a saw against that line is difficult to do without crossing the line.  If you’re sawing off a tenon cheek, for example, you want that shoulder cut cleanly and free from defects caused by the saw jumping the line when trying to get the cut started.  So, step two is to chisel a little V that butts up against the knifeline you created prior.  You obviously want to remove the material on the waste side of the line.  Now drop the saw in the V and go to town.

Using a typical marking gauge, scribe the line you want to cut to in your board.

Angle a chisel into the knifeline (obviously on the waste side) to create a shoulder.

I got thinking about this two-step process, looked at my Veritas dual marking gauge, and went to work.  The two posts each have a dedicated cutter at one end and nothing at the back end of the post.  I added a 45 deg bevel to the back of one post, tapped a 4-40 hole (which matches the holes at the front of each post) and installed a prototype cutter.  When the post was re-worked, I installed it so the tips of each cutter lined up.

Dual marking gauge in its original state.

One post removed for modifying.

Back end of the post with its bevel ground in.

… and now the tapped hole for the cutter.

Modified angled cutter installed next to the standard vertical cutter.

When viewed from the side, the blades just line up at the tips of the cutters.

The idea at this point was to drag the gauge across the board in the usual fashion, but after the vertical cutter has scored its line, the angled cutter would follow along scoring the little V typically removed by a chisel.

Test cut: after a couple passes with the gauge the waste material lifted right out.

So how did it work?  Not too shabby.

Gauge/chisel line in the back, dual marking gauge line in the front.  Virtually identical.

When viewed from the side, you can see each method gave a nice V with one side vertical, one side angled.

I had no trouble tracking the line with the saw. No jumping or wandering.

To be really effective I’d like to have a pair of custom cutters made up, that’s where I’m headed next.  For now it worked well enough to prove the concept.  I like the fact that the modification is really just an addition to the existing gauge without taking anything away from tool as it was originally intended to function.  Just flip the post around and you’re back to two vertical cutters.  So until new cutters are made, that’s all folks.

-WMT

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In:In the Shop

Comments Off on Setting up a Scraper Plane

If you’re new to scraper planes or scrapers in general, you may want to read this first.

My Lie-Nielsen #112 scraper plane has become indispensable to me since I purchased it about a year ago.  Whether I’m dealing with exotic woods, interlocking grain, or just smoothing a knot with the usual grain reversal surrounding it the scraper plane does it all and I would not be without one at this point.  But maintaining a scraper plane can be tricky and unlike hand planes, there isn’t a lot of information out there on how to set them up.  Hopefully this will help (so please tell your woodworking nerd friends).

The 112 in need of some maintenance.

I start by taking the blade out (TIP: push it out through the bottom of the sole so you don’t ding the cutting edge) and cleaning out any debris.  My handles were a bit loose, so I snugged them up while I was at it.  I also removed the cap screw, cleaned off the threads, and added some oil to it before re-installing it.

Disassembled for cleaning.

Next I took some freehand test cuts with the blade to see if it was still sharp.  It produced mostly dust so it was time to sharpen.

Dust means the blade is dull. You want to see shavings.

The blade is sharpened just like a plane iron, except I use a straight edge (not cambered) with my scraper plane.  The bevel is also honed at 45 degrees, much higher than the 25-30 degrees found on a typical bench plane.

The bevel is honed at 45 degrees.

With the blade polished, I turn a hook.  This is similar to forming a hook on a card scraper, but because the edge is at 45 degrees (card scrapers are honed at 90 degrees), I just apply some pressure to the tip of the bevel with a burnisher to create the burr or hook.  This can take a little practice, but you will quickly learn what a “good burr” feels like.

Clamp the blade in a vise and turn a small hook with a burnisher.  Test the cut, increase the hook if needed.

With the hook formed, I start taking test cuts by hand and look for two things.  First, is the hook where I want it?  If it’s too large I’d have to grind it off and re-sharpen (though that’s never happened), if it’s too small I can put it back in the vise and increase the hook with more pressure and more passes from the burnisher.  The second thing I look for is the optimal cutting angle, which is a little different every time as the hook is turned by hand and isn’t 100% identical from one sharpening to another.  I hold the blade at the desired angle and adjust the frog assembly to match.  This way I know when the blade is installed I’ll be getting the best shavings possible.  The adjustable frog is not a feature found on smaller scraper jigs like the Stanley #80 and it’s one of the major benefits of using a dedicated scraper plane.

I’m getting shavings, not dust. The blade is held at the desired angle and the fog assembly is adjusted to match.

Now I simply install the blade (again, through the bottom of the plane so the hook isn’t damaged by sliding through the frog assembly) and set everything flat on the bench.  Make sure there are no shavings or debris preventing the tool from laying dead flat.  Press the blade down so it touches the bench firmly, then tighten the cap screw.  This should leave the blade more or less parallel to and flush or just below the sole of the plane.  Take a test cut.  If the blade is skewed or not protruding far enough, minor adjustments are made with light taps from a small hammer.  Brass is preferable so the blade isn’t damaged.  I own one from Lie-Nielsen and another from Sterling Tool Works.  Both work great.

Nice full-width shavings with a perfect surface left behind means the tool is working as it should. Depth and lateral adjustments to the blade are made with a small brass hammer.

After a little trial-and-error you should be getting wide, fluffy shavings with a tear-out free surface left behind.  Once I was satisfied on my scrap piece of walnut I had some actual work to accomplish on some Bocote and Chakte Viga.  No problem… except that Bocote smells like a wet dog.

Fancy pants woods giving you tear-out problems?                 Not anymore.

-WMT

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In:In the Shop, Vintage Tool Talk

Comments Off on A Custom Fishtail Chisel

We make winding sticks… lots of them.  Each set has four trapezoidal pieces of inlay, each with two sharp corners that need to be cleared out.  So for a batch of 50 sets of sticks I have 400 corners to clear.  Thus far I have used my Lie-Nielsen 3/8″ fishtail chisel, but it’s too narrow and the fishtail angle is too shallow to really reach the corners, so I have to reach down from above and scoop out the waste.  It works, but it’s not ideal.

My first thought was to buy their largest size chisel (5/8″), but I scoped it out at the Lie-Nielsen event in Brooklyn a few weeks back and found it was also too narrow and too shallow on the side angles to give me what I wanted.  I decided to try modifying a vintage chisel if I could find one suitable for the job, so here’s the rundown:

I found this Stanley chisel (with steel through the entire body) which had been ground down quite a ways for $9.  Normally I wouldn’t want to pay even $9 for a chisel that was so short, but for this task where I want to be closer to the work it was perfect.  The steel running through the handle also puts good weight in the hand and balances the tool nicely, so $9 was worth it.

The chisel as purchased, prepare to be decimated.

I painted on some machinist layout fluid, scratched in some general guide lines to grind to, and started hogging off material.  I’ve had a few people as about the risk of removing the temper from the steel during this process so I want to address that up front.  To avoid ruining the steel, you need to avoid over heating it.  This starts by using fresh abrasives.  I was grinding with a freshly dressed grinding wheel from Norton.  I held the tool with my bare hands so I could feel when it started to warm up, then I cooled it in water.  I also don’t grind up by the tip of the tool, this material is so thin that it will heat up too quickly and be ruined.  Any final grinding of the tip was done by hand on sandpaper and finished on waterstones.

Heavy material removal completed from the bench grinder. Time for the belt sander.

When I had the sides brought in I needed to refine the shape so I switched to my belt sander outfitted with metal grinding belts (Alumina Zirconia).  This worked extremely well and was basically trial-and-error process.  I’d grind some metal, check my progress, draw new target lines occasionally, and grind some more.  Eventually I got the shape I wanted and went from a 40 grit belt to an 80.  Refined things a bit further, then polished it up with a 220 grit belt.

My restored belt grinder… too pretty to just grind metal on, so I covered the walnut with some thick paper to avoid getting metal embedded in the wood.  Worked like a charm.

Shape being refined on the belt sander.

After the grinding was finished, I hand filed a few areas and then sharpened the blade.  I started with sandpaper as this was the initial sharpening/flattening of the tool.  After sanding up to 320 grit I switched to my waterstones and polished the tool up to 8,000 grit.  This was a freehand operation given the shape of the tool doesn’t really fit the standard sharpening jigs.  I use the sharpening jigs whenever possible and am not ashamed to admit it, but I can freehand when necessary.

The finished tool compared to my 3/8″ Lie-Nielsen. I had a slight ding on the bevel near the cutting edge, but it’s not at the cutting edge and will be ground off in future sharpenings. I didn’t remove it now because I’d be wasting several sharpenings over a small cosmetic flaw.

The chisel being used as designed. You can see that it can reach all the way to the corner of the inlay pocket and still has a little clearance between the chisel and the pocket’s side wall.

I tried the chisel out briefly and it works brilliantly.  Overall it took $9 and between three and four hours of work, and that’s from the time the tool was untouched to completely finished.  I did give the handle a quick sanding and refinishing, but nothing fancy and now it’s ready for years of service.  Time to get some work done.

-WMT