Drilling down – mortising the staked work table

Although my workshop is very much hand work focused, there are a couple of machines I use, and enjoy using. The drill press is one of them. I started out, nearly a decade ago, with a bench top drill press that was fine for grunt work but exhibited too much run-out for precision drilling. So towards the tail end of last year I finally upgraded to a new Jet floor standing model, which has sufficient capacity and accuracy to last me decades. The impetus for making the upgrade was the need to drill 2″ mortises through the battens of the staked work table to accept the leg tenons.

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The banjo jig is my platonic ideal of a workshop appliance – dirt simple and effective

Because the mortises are drilled at an angle simply securing the battens to the drill press table will not work. And so I built the “banjo” jig Chris writes about in the Anarchist’s Design Book. Nothing fancy – just two large squares of 3/4″ ply with a pair of cheap hinges at one end to provide a pivot point. But simple is how I like my jigs, and “banjo” will provide solid service for many tables, chairs and angled holes for years to come.

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Cutting guide wedges with the Bad Axe Bayonet

To establish the correct angle for the jig, and to ensure repeatability of setting, I cut two 16 degree wedges out of some scrap pine. In doing so, I was reminded just how blindingly accurate the Bad Axe Bayonet saw is – both wedges were bang on on the right angle straight off the saw, no fettling needed. I’ve said it before, but there is some serious alchemy in this saw. Inserting the wedges between the leaves of the jig held the top leaf at exactly the right angle for the leg mortise. If I come to drill mortises using different resultant angles, then it will be easy enough to cut wedges to match.

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The wedges help to set the correct angle for the banjo jig

To locate the batten on the jig, I chucked a fine brad point drill in the drill, and positioned the batten by eye so that the sight line lined up with the centre of the drill press. After loosely clamping the batten in place, I then tested the location by lowering the drill bit to the work piece. What I wanted to see was the tip of the drill bit following the sight line until it hit the centre point of the mortise. Gently tapping the batten with a mallet made very controlled adjustments until everything was lined up.

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Game time!

With the wedges cut, the jig clamped to the drill press table, and the batten clamped to the jig, it was game time. Drilling the mortises is straight forward, providing you take care to get the batten in exactly the right position, and are sensible about how fast you try to drill out the 2″ mortises. My own observations are as follows:

  • 3/4″ plywood loves to vibrate. Bracing the workpiece with a suitable piece of scrap between the leaves of the jig and directly under where the mortise will be drilled, is essential. This will increase the stability of the jig and stop the top leaf from wobbling about when the drill bit engages. The wedges set the angle, a larger brace keeps things stable.
  • Go slow. Even with a powerful drill press, drilling a 2″ mortise in hard maple is a tough job. Set the drill speed to as slow as you can, and take very small nibbles with the bit, backing off regularly.
  • Clamp everything. If the batten, or the jig slips, you’re going to have a lot of clean up work to the batten, and centring the batten in exactly the right position may not be that easy
  • Keep your quill and chuck spotlessly clean. Because the mortise is drilled at an angle to the work piece, for the first part of the chuck’s travel the bit will only be engaging on ine sid. Drilling a large (2″) angled mortise with a forstner bit if there is even the tiniest spot of dirt or grease on the quill will result in the chuck, and bit, wobbling when you start to make the cut, and taking to the air shortly thereafter. Ask me how I know this. Cleaning the quill and interior of the chuck will keep everything working as it should, and avoid airborne machinery. In fairness, I had wiped down the quill and chuck when I first assembled the drill press, and it has worked flawlessly on other tasks. After quickly wiping down the quill and interior of the chuck, the drill press cut the mortises without any complaint. But a good lesson is always worth learning.

All of the preparation and fussing over the set up paid off, and drilling the mortises was very straight forward. My favourite method to bore holes is still with my 1923 North Bros. brace, but on a hole of this diameter the drill press jis definitely more practical. I still need to sharpen the 2″ t-augur that arrived in November, and once I have done to I will have some experiments to see how easy it is to drill the same mortise by hand.

With the mortises drilled, it was then a matter of gluing up the leg assemblies. But for that, you will have to wait for the next post.

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One leg assembly glued up and wedged

On monster dovetails, and embracing the fear

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Setting the depth of cut with blue tape and a small combination square

The staked work table build is pretty straight forward, and on the whole very enjoyable. I mean, if you can’t enjoy octagonalisation that means you’re already dead inside, right? But the one stage of the build which has given me the fear is cutting the sockets for the dovetailed battens. Although the task itself is not that complicated, it really is a one shot deal, with very little opportunity to remedy any errors. The sockets need to match the profile of the battens, and a tight fit is necessary to restrain any seasonal movement of the top. Because the sockets run the full width of the top, any gaps at the front of the table will be extremely noticeable. It is probably no surprise that the opportunity to ruin the top was something that loomed large in my mind when I stepped up to the bench to start cutting.

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My off-hand keeps the saw cutting against the side of the batten

When cutting the sockets you use the battens to guide the saw, and providing you make the cuts with care, this method should ensure that the socket matches the profile of the battens. I had originally made the battens over length by a couple of inches, and I decided to leave them at this length when cutting the first wall of each socket as this would provide a greater surface area for the saw to register against. As the front end of each batten was square, I was able to clamb the battens in place flush with the front edge of the table top, making sure that they were parallel to the ends of the top. I decided to cut the innermost edge of the sockets first, although there is no real difference in which side you cut first – the main thing is to be consistent as this helps to avoid mistakes.

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When the blue tape hits the surface of the table, stop cutting

As I’ve written about before, I have a (ahem) healthy nest of saws. I spent some time considering which saw would be most appropriate for these cuts, and decided to go with the Roubo Beast Master by Bad Axe Tool Works. Although my Beast Master is filled rip (and this is a crosscut operation), it had a number of significan attributes which I wanted for cutting the sockets (and not just because Mark promises it cures baldness). The robust saw plate meant that the saw would be able to withstand being pushed across 24″ of hard maple without suffering undue strain, and would hug the batten so as to cut the right slope angle. Finally, the 5″ depth of plate under the saw back means that the handle would not foul on the batten, as would happen with a shallower saw.

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The Beast Master leaves a crisp kerf

 

So, with my saw selected and the battens clamped in place, it was time to be brave and start slicing up the table top I’d spent previous weeks preparing. When making the cut, my off-hand pressed the saw plate into the batten just above the toothline, while I pushed the saw forward with the open palm of my on-hand in order to avoid tilting the saw or twisting it away from the batten, only wrapping my fingers around the handle to pull the saw back for the next stroke. Once the kerf was established, the saw cut down to depth smoothly and rapidly, and there was minimal chipping out on the exist side of the cut despite using a rip saw (all of the cuts were made from the front edge of the table towards the rear edge so that any chipping out would be on the back edge). I marked the depth of cut on the saw plate with blue painter’s tape, and once the tape hit the surface of the table I stopped cutting. The Beast Master left a crisp and clean kerf across the table.

 

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Trimming the battens to length

Because the battens are angled, determining the location of the second side of the socket takes a bit of lateral thinking, and Chris covers this very clearly in the book. I cut the battens to length using a 16″ hybrid filed Bad Axe tenon saw, and used the offcuts to mark off the second side of each socket, allowing for the set of the Beast Master. The process for the second cut was the very much the same as the first, following which I put the battens aside while I cleaned out the waste. I hogged out the majority of the waste with a 3/4″ chisel and mallet, working from both ends into the middle of the table to avoid spelching. Once I was close to the bottom of the saw kerfs, I switched to a large router plane to clean up the bottom of the socket.

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A chisel and mallet makes short work of cleasring out the socket

With the sockets cleaned up, it was time for the moment of truth, and I fitted the battens using a 1lb lump hammer to drive them in. The fit was good and tight without being too much of a squeeze, and with no real gaps at the front edges, which is exactly what I was looking for. As a final step, I took two fine shavings from the middle of each side of both battens, just to ease the fit a little bit (but without reducing the efficacy of the batten).

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Test fitting the batten.