Archive for ◊ April, 2020 ◊

Author:
• Thursday, April 30th, 2020
making a dovetail marker

The process I used to construct these markers ensured their accuracy.

I used bubinga but many dense, fine-grained hardwoods such as hard maple would do fine. Start with a 1 3/8″-thick, flat board without internal stresses, at least 12″ long and 5″ wide for safety, with a straight, squared long grain edge.

Using appropriate safety precautions, make a 1″ x 1″ rabbet on the long grain edge. I used many shallow passes with a 1″ diameter straight bit on the router table, finishing with a light pass over the entirety of the inside surface.

On the table saw, rip away a 1 1/2″ strip containing the rabbet. 

For safety and accuracy, short pieces – the markers themselves – will be cut on the table saw from this long work piece.

Two principles guide the process. We want to work with the rabbet always facing the blade to eliminate even the minor tear out that can occur at the trailing edge of a cross cut. This keeps the inside edges of the marker crisp. This also keeps the work piece stable against the fence.  

We also do not want to reset the miter gauge in case there is even the slightest inconsistency from the right side to the left side settings.

So, prepare by making a wedge. Use the miter gauge to cross cut a squared edge on a piece of scrap or MDF. Then set the miter gauge at the desired dovetail angle and cut off a narrow wedge. Glue sandpaper to the angled edge, and to the straight edge if you don’t have sandpaper on your miter gauge fence. 

Use the wedge against the miter gauge fence, set at 90°, to cross cut the end of the work piece held against the wedge. This creates one side of the marker (as in the photo at top). Then, flip the wedge end for end, and cross cut to produce the finished marker about 1 1/4″ wide (as below).

making a dovetail marker

Check the marker with a square and bevel gauge. Both sides should be the same. Chamfer the non-working edges on the outside. Label it with the dovetail slope – I carved the numbers. The oil (non-film) finish has worked well over the years.

For reference: 5:1 = 11.3° 6:1 = 9.5° 7:1 = 8.1° 8:1 = 7.1°

Author:
• Thursday, April 30th, 2020
dovetail marker

Make dovetail layout easier and speedier with these shop-made markers. I have been using them in my shop for many years. 

Unlike most commercially produced markers, they allow you to pencil the entire length of the line on the end grain and face grain with one positioning. This produces an accurate alignment of those two lines, which in turn helps you saw accurately. They work for tails-first woodworkers as well as pins-first iconoclasts.

The outside dimensions are 1 1/2″ tall, 1 3/8″ deep, and about 1 1/4″ wide. There is 1″ of length on the inside of each arm of the marker, which will accommodate almost all dovetailing for most woodworkers. 

They are easy to make in a variety of dedicated dovetail slopes. No more setting a sliding bevel.

dovetail markers

You can also use them to square the pin layout on the end grain (that you transferred from the tails) down the side of the pin board with a pencil to help guide your saw. 

Note that there is no “relief” at the inside corner of this marker. All the working edges are crisp. A relief at the inside corner, though present in many, if not most, commercial markers, is unnecessary and misguided. Come on, who has “saw whiskers” on the pieces they are about to dovetail? The relief causes a break in the pencil line at the corner of the work piece, thereby disturbing an important visual link for guiding the saw.

The construction method makes these markers as accurate as anything you can buy. And, of course, the cost to make them is negligible. 

I detailed their construction in an article in Popular Woodworking magazine, November 2009, issue #179, but now I will present show the simple process here on the Heartwood blog in the next post.

Author:
• Friday, April 24th, 2020
dovetail markout

In writings from the 1970s and 80s, Charles Hayward, Ernest Scott and others discuss using shallow saw kerfs to mark the tail layout onto the endgrain of the pin board. The idea is to drag the saw through the tail kerfs, which act as guides. There is no instruction to laterally displace the tail board to compensate for the width of the kerf, and so the intention is to saw to one side of the mark.

I find it difficult to start the cut by following such a mark. Moreover, if the start of the cut is imperfect, it is too easy to become disoriented by the hacked up endgrain surface. I do not like or use this method. 

A better method is to use shallow kerfs to guide the placement and engage the saw as you start to saw the pins. Of course, you must laterally displace the pin board to compensate for the kerf thickness. Otherwise, the sockets will be too wide by the amount of two kerf widths. 

I do not know who first came up with this method. I first saw it on Kevin Drake’s website. More recently, dovetail master Rob Cosman, who mentions that he learned it from The Encyclopedia of Furniture Making by Ernest Joyce, has taught it. I suspect that like most woodworking methods, it has been around longer than we realize. 

In the demonstration photo above, the tail board is shifted one kerf width to the left to prepare for making marks through the kerfs on the right side of the tails. This puts the kerf marks in the waste wood of the sockets on the pin board.

Below, the tail board is shifted to the right for making the marks through the kerfs on the left side of the tails.

dovetail mark out

To gauge the shift, I used a shim that is a tight fit in a kerf made by my dovetail saw. You can regulate the tightness of the joint and/or allow for a margin for error by adjusting the thickness of the shim. Making a slightly thicker shim (say .002″ or a piece of Scotch tape) will make the sockets slightly undersized. This may be good for softer, more compressible woods. 

Make the kerf marks before sawing or chopping out the waste between the tails. This gives you a tighter guide. Note that you have to saw the tails square or at least to a one-sided tolerance.  

You will need a specialized tool to make the kerf marks. With a Western saw, it is impossible to make them on the push stroke, and slow going on the pull stroke unless the wood is quite soft. Japanese saws do not work well for this because the teeth do not extend to the toe of the blade. 

Kevin Drake’s system uses a hawk bill scraper, which acts as a saw with a single big tooth, while Rob Cosman sells a nifty marking tool that is essentially a tiny pull-stroke saw with the same kerf width as his dovetail saw. Note that Drake’s system uses a special dovetail saw with no teeth at all at the toe to aid in registering the saw in the kerf mark. 

Unlike when using a scriber or knife, it is easy to inadvertently shift the tail board when making these pronounced marks in the pin board endgrain. A dovetail alignment board of the sort used by David Barron is one way to minimize this. This tool is a great aid to dovetailing no matter the transfer method you use.  

Another method, is to make a very shallow rabbet (1/32″ is enough) on the inside face of the tail board. This gives a dead-on, steady alignment of the tail board against the pin board. I really like this trick for dovetailing in general and use it especially for wider boards. I recall first learning it from an article by Rob Cosman in Popular Woodworking (April 2006), where he notes that he learned it from Ian Kirby. 

Remember, any method of marking out the pin board goes better if you are working on cleanly sliced endgrain, at least from the table saw or, better, from the shooting board.

So, there you have it: three posts on the critical step of transferring the tail layout to the pin board. I suggest experiment and choose what works for you! My go-to method is still the scriber. I cut my first dovetails 40 years ago but I still like to explore and refine different methods. I’ve only experimented with the kerf mark method, but I may adopt it for some circumstances. I like having options as various woods and constructions favor different methods.

Author:
• Monday, April 06th, 2020
V point marking knife

Continuing the topic of transferring the layout of the sawn tails to the endgrain of the pin board, the purpose of these posts is not to argue for the superiority of any one method but rather to array the options to help you choose what works best for you and the specific project at hand. I vary my method depending on the species of wood, the type of dovetail (e.g. through or half-blind), and the thickness of the wood. 

V-point knives seem to be popular for this task, especially thin models that can slip in between narrowly spaced tails, such as the beauty made by Blue Spruce. Without a doubt, many highly skilled woodworkers produce excellent results with these tools, but I find it difficult to see the knife line. 

I do not mean that it is difficult to see the fine knife line at first, but when I start sawing across the endgrain, I cannot visually keep track of that skinny line to confidently split it with the saw. Chalking the endgrain is not much help. The scriber makes a V-groove that I can track and split better while sawing, and furthermore allows me to better see how I’ve done afterwards. I also find that a V-knife sometimes catches the side grain of the tail, slicing off a hair of it and slightly dislocating the layout line, albeit in the safe direction. 

Ian Kirby, one of my all-time favorite woodworking teachers, has favored a pocket knife for this task. This is not my preference but again, it is another option to consider. The sheepfoot in your three-blade stockman or a Wharncliffe blade like in this lovely Kershaw would be good choices for this because it is easy to reach the tip all the way out to the base of the tail.

Kershaw knife

One knife that I sometimes use is my modification of a Pfeil #13 chip carving knife. I removed the edge and a bit of the width from all but the first 1/4″ of the blade. I also ground the sides to a nearly flat single bevel. (The Pfeil #3 knife would probably also work.) I find this modified tool very easily reaches to the base of the tail and follows the wall of the tail with very little tendency to slice into it. So, I like it better than a V knife but I still usually have the dilemma of following a pretty fine knife line. 

modified Pfeil #13

What about the roll of blue tape in the photo in the previous post? Mike Pekovich, Creative Director of Fine Woodworking magazine, and a very skilled and thoughtful craftsman, covers the endgrain of the pin board with blue tape. (FW #240) He then knifes the tail outlines into the tape, removes the tape over the waste wood, and saws just adjacent to the remaining pieces of tape, which represent the pins. Clever!

I experimented with Mike’s method. It surely has merit, and some will love it, but I am not comfortable with it. The pieces of remaining tape can move, especially if you knick them while engaging the saw, and when they do move, I’m lost. I also do not feel comfortable with a piece of tape determining the registration of the saw. But give it a try, you might like it. 

Next: using saw kerfs as layout.

Category: Uncategorized  | Tags:  | 4 Comments