Wraparound Dovetails – How I Fit Them

Most of us are familiar with the techniques for fitting dovetails during construction.  You cut the pieces to size, mark your dovetails, and cut away.  Even if you machine-cut, the process is basically the same.  Everything is measured from the end of the board.  However, there are times when this approach doesn’t work.

This blanket chest is a perfect example of this.  Christopher Schwarz’s Anarchist’s Tool Chest is another.  In both cases, a base or dust seal wraps around the basic structure of the chest, and is dovetailed into place.  The problems start to arise when you realize that the pieces cannot be precut to length, but must be fitted to the existing structure to ensure a good fit.  No, measuring with rule is not a substitute for a good direct measurement.  Of course, your measurement doesn’t tell you how far past the end of the casework the board should extend for the overlap that will give a good, snug dovetail.  This is how I do it:

Start by dovetailing one corner to act as a reference, leaving the board overlong.  Then, with the assembled dovetail snugged into place, mark the corner of the casework on the other end.  A marking knife will work, but I find that a pencil will angle into the corner more easily without wandering.

Next, stand the opposing board (or an offcut of the same) on edge on this board, with the inside edge flush with your pencil line, and mark the location of the outside face.  This measurement isn’t really critical – you just don’t want to be too short.  Next, crosscut the board to just outside this last line to establish the rough length.

Now comes the trick.  Take your marking gauge, which you already set while cutting the first dovetail, and place it against the sawn end of the board.  There will probably be, as shown above, a gap between the knife/pin and the pencil line.  Simply plane away the excess with your shooting board (you do have a shooting board, don’t you?) until the marker touches the far edge of the pencil line.  If your marking gauge was set correctly in the first place, you should now have the correct amount of overlap to yield a dovetail that wraps snugly around the casework.

With a little thought and modification, this technique will also work with dovetailing jigs.  Simply set your marking gauge to the base of the first dovetails, and proceed as above.  Since all you’re doing is effectively cutting a board to length, the dovetailing method is really irrelevant.  Give it a try!

Blanket Chest – Drawing a Bead With a Scratch Stock

In the midst of finishing up the four chest frames, I decided to take a detour to the bottom.  I started with 3″ wide boards 3/4″ thick, and did a simple shiplap using the dado blade on the tablesaw.  However, I didn’t like the overly plain look, even if it was the bottom, and would rarely be seen.  What I really wanted was a beaded edge detail to dress things up just a bit.  However, I didn’t own a beading bit for the router.  What to do?

I had recently seen a Fine Woodworking video of Garrett Hack making and using a scratch stock, and decided to give it a try.  My first stop was at the box store for a long thumbscrew and a thread tap and drill bit set to match.  Then, I got to work.

I cut a small piece of white oak to a size that was comfortable in the hand.  I laid the thumbscrew on top, and marked a line around the block just up from the end of the screw.

I used the tap’s pilot bit to drill a hole into the end of the block stopping after I passed the line.  This would allow the tap to cut threads all the way to the slot-to-be.  I then took the tap, and carefully cut threads all the way to the end of the hole.  This long column of threads gives the screw more support, with less chance of the metal screw stripping out the wooden threads.  Marc Spagnuolo has a great video of this process available on The Wood Whisperer’s website.

After tapping the screw hole, a saw kerf provides a slot for the scratch stock blade.

I rounded the edges and corners slightly for comfort, waxed the screw, and ran it into the hole.  With that, the blade holder was finished.

To make the blade, I took a small square of old saw blade and dressed the edges smooth and square.  Then, using the appropriate size of file, I cut a semicircular profile into the blade, and then smoothed the concave surface with sharpening slip.

Actual sharpening is done by honing the surfaces of the blade to a mirror finish, much like flattening the back of a chisel or plane iron.  I’m a diamond hone fan, but any sharpening system will work.  Repeating this process will usually restore the blade to cutting shape without having to touch the profile itself.

I mounted the blade in the holder so that the inside curve ends just at the surface of the wood.  If you were to move it outwards a bit, you would have a flat step on the outside edge – certainly an option if that is what you want.  A twist of the thumbscrew locks it in place.  I apologize for the blurry pictures, but it took five tries to get one this good.  You get the idea.

To use the stock, simply move it back and forth along the edge of the board being shaped.  Often, it will cut better in one direction than another.  In the picture above, the cut is being made towards me (away from you).  Notice that I’ve got the scratch stock angled slightly – it’s important that the cutting edge trails somewhat until the last gentle pass or two.  Think about the way you use a card scraper, and you’ll get the general idea.  The rest is a matter of feel and patience – don’t try to cut too fast.

These are the completed bottom boards, and you can see how the beads really dress up the otherwise plain shiplapped edges.  When I attach them to the bottom of the blanket chest, I’ll use a couple of finish nails or brads to space them so that the actual gap is the same as the groove beside the beads.  Not only will this give a good look, but will allow for expansion and contraction.

The scratch stock is an amazingly simple tool, and cost me all of $1.40 for the thumbscrew.  The thread tap and drill bit were about $4.00, and will surely come in handy adding screw threads to other projects.  The saw blade was just laying around in the way.  While it’s certainly not as fast as a router, it allows you to duplicate existing profiles easily, especially for smaller projects or restorations.
And, it won’t break the bank like a collection of router bits.  For the price, it can’t be beat.  Give it a try.

Frame Tuning Tip

Any time you make a frame-and-panel assembly, and especially with hand tools joinery, some of your joints will be a bit out of line.  It’s nothing to be embarrassed about – it happens to all of us.  The trick is to be able to make corrections for the irregularities with a minimum of effort.  The best time to do this is before your final glue-up, and this is the technique I use:

Dry assemble the frame, and look for any places where the joint is out of line.  When you find one, use a pencil to mark along the edge of the adjoining piece.

This will give you a guide line to show you the material that needs to be removed.   Take a hand plane and plane down to the bottom of the pencil line, feathering the cut in from what is the left-hand edge in the above photo for a smooth transition.  As you get close, stop and make at least one test fit to double check – it’s easy to overshoot.  Once you’ve planed to the bottom of the line, the joint should be a near-perfect fit.

Give it a try!

Quick Tip – Keeping Good Records.

There’s an old saying that, “If you didn’t write it down, it never happened.”  While that’s not exactly true for woodworking (that project you built came from somewhere, after all), the principle of writing things down is still a good one.  Most of my projects are built from scratch, often with nothing more than a photograph or two to work from, and all of the details worked out as I go.  Even when working from plans, I’m notorious for changing details or resizing components to fit my own ideas.

Historically, I’ve worked these things out on whatever was handy:  the back of a picture, a piece of scrap paper, and occasionally a paper towel (seriously!).  The problem with these is that they tend to wander off after the project’s completed – and sometimes before.  Granted, you may never build that piece again, but haven’t you wished from time to time that you could refer back to something you did years before?

My solution to this is a bound journal.  They don’t have to be big or fancy – something as simple as a $2.00 composition book will do the trick.  The key word here is bound.  Loose-leaf binders and spiral-bound notebook pages tend to tear out or get damaged, whereas a bound journal has a much higher survivability index in the shop environment.

I try to document all the details of the project as I go.  Basic dimensions and lumber requirements are a good place to start.  I also include the details of important joints, and the reasoning behind some of my choices.  A step-by-step record of the construction process is often helpful, and I try to make note of any mistakes, and why I made them.

I’ve also found that it’s crucial to detail the finishing process, with particular reference to any stains or dyes I used or, more importantly, mixed.  More than once, I’ve needed to re-create a dye mixture to match an existing piece of furniture, and had no idea of what I had done the first time.

Lastly, at the end of the entry, leave some space to come back and make comments later.  From time to time, something that seemed like a good idea during construction came back to haunt me, and was added to the record.  Reviewing such after-action observations can be very helpful in making better design choices on future projects.

Give it a try!  Months or years from now, you’ll be glad you did.

Mortise Chisel Depth Control

I’m a big fan of hand-chopped mortises.  There’s something about the seemingly-contradictory requirements of power and finesse that appeals to me.  The problem with them is that, unlike drill presses, there is no depth stop to keep you from happily chopping your way right out the other side of the board.

The  most common way suggested to prevent this  is to wrap a piece of tape at the appropriate point on the chisel blade, and stop when you reach it.  The problem with this method is that you rock the chisel to lever chunks out of the mortise as you work your way deeper.  Invariably, my tape ends up looking like the example above.

I have found a better solution in the Sharpie permanent marker, which isn’t as permanent as you might think.  A simple line on the chisel blade, and you’re set to go with a mark that won’t wiggle and bunch out of place.  When you’re through, a wipe with denatured alcohol leaves you with a pristine chisel blade again.

So much for permanent.

Close At Hand Holdfast Pads

Holdfasts are wonderful devices.  Their ability to secure wood to the benchtop with a single mallet tap can seem almost magical some times.  However, they have a tendency to dent the surface of your workpiece, especially in softer woods.  I’ve tried gluing on leather pads, but found that they tended to come loose after a short period of time.  A block of wood works well, but a piece of the right size can sometimes be difficult to locate when you need it.  Plus, a scrap off the shop floor can have a chunk of “something” imbedded in it, the impression of which can be transferred to your work.

My solution is a pair of dedicated holdfast pads.  You’re probably wondering what makes these different from the nearest piece of scrap.  I’m glad you asked!

Functionally, there is no real difference.  The biggest difference is in what you do with them when not in use.  These pads were cut from a piece of offcut from a pine tenon cheek, so they are basically non-mar.  The piece was thicknessed carefully to ensure that two of the pads, when placed together, would fit in a slot in the French rack on the back of my bench.  They were sized to this end, with a modified “T” shape to keep them from slipping all the way through the slot.

So, when not in use, the pads reside in a slot in the back of the bench, taking up little room and not sticking up far enough to get in the way.  When needed, they are close at hand to be grabbed, used, and then replaced in their slot.

If you don’t knock them off on the floor and lose them in the shavings that you haven’t swept up, that is.

Panel-Raising Jig Completed

As I promised, the panel-raising jig is now finished.  The basic structure is unchanged, but the addition of a vertical fence and a lever clamp converted the proto-jig into a tool for panel-raising.  The clamp is the Quick-Set Heavy-Duty Lever Clamp from Rockler (item # 29485), which happens to be on sale right now for $9.99 instead of the usual $15.99.  This might be a good item to stock up on for future jigs.

Don’t worry, the bottom screw hole in the fence doesn’t have a screw in it.  It was a temporary holding point while the other screws were driven, and the clamp was attached.  By the way, pocket hole screws are a great way of attaching something like this clamp to the project.  Their washer-head design snugs down over the baseplate holes quite nicely and allow you to adjust things slightly if need be.

Now, I have to determine the specifics of how to set up to raise the panels.  There are a lot of variables to take into account, so I’ll have to glue up a few test panels to work the details out.

Stay tuned!

Proto-Jig: Imagine the Possibilities

Whaddya think?  Neat, eh?

I can hear you now: “Eh, sure!  What is it?”  Wrong question.  The right one is, “What could it be?”  The correct answer is, lots of different things.

In this case, this is the basic framework for a panel-raising jig for the tablesaw.  I’ll be adding a backer strip and toggle clamp once it arrives from Rockler, and I’ll give you another look when that’s done.

For now, look at this from a different point of view.  This is a tall board held at right angles to the tabletop with an assembly that straddles the rip fence and can slide to and fro.  The spacers were cut a hair wider than the width of the rip fence and then planed down for a slightly snug fit.  Add a little wax and everything slides smoothly, and any residual binding will rapidly disappear.  Some people make these with only one spacer, but I like two for the added rigidity.

What you really have here is a structure that has the capability to be used for a number of different purposes.  Panel-raising jigs and tenoning jigs are just a couple of the possibilities that come to mind.  Anything that requires a board to be held vertically on the tablesaw is fair game for this approach.

What about you?  What are your ideas for using this type of proto-jig?  Leave a comment and let us know.

I’ll be revealing the dimensions for the blanket chest and how I arrived at them later this week.  Stay tuned!

Quick Tip – Oiling Spoons

I enjoy carving spoons and other small kitchen ware and commonly use walnut oil as a finish, but I don’t make these items frequently or in large batches.   I know that many who do use some sort of soak tank to immerse their woodenware for a prolonged immersion in the oil of their choice.  In my case, however, such a setup is impractical and requires a large amount of oil.  Since I may do a piece every month or two, I needed a system that allowed me to immerse the piece in oil without requiring a tank or a gallon of oil.

My solution?  A gallon Ziploc bag.  I place the item in the bag, and addd a small quantity of oil.  I then squeeze all of the air out of the bag and let things soak.  Since there is no air, the small amount of oil ( about an ounce or so) easily covers the surface of the spoon completely, and allows the wood to take up as much oil as possible.  You can see in the photo above the small amount of oil pooling in the lower left corner of the bag.  A quick daily agitation ensures that everything is still coated, and I can add more oil if needed.  Works like a charm!

Shop Tip: Marking Dark Wood

The shaving rack project brought home to me the difficulty of working with dark woods such as the ebony featured in this project.  Regular pencil lines are practically invisible, and even scribed lines fade into the background without proper lighting.  One thing that can often help is colored pencils.  They are available at any office or art supply store, and come in a range of colors.  White is the most useful choice on nearly back woods such as ebony, but other colors such as bright orange or blue can be helpful on other species.  While they often mark poorly on very smooth woods due to their high wax content, the leave a very visible line on surfaces that are still a bit rough.  In addition, they are wonderful for highlighting the kerf left by a marking knife or gauge.  Grab a couple and give them a try!