The DowelMax jig (with musings on the Miller dowel system)

At the moment I have very little time for the actual woodworking I would like to do – partially due to the cabinetry I’m building for the basement, and renovations that have taken too many years to finish. Years ago when I drywalled the basement I left cavities in some of the walls in which to insert bookshelves. These are utilitarian bookshelves made of maple (5.5″ deep) – sturdy enough to hold paperbacks, DVD’s and probably all the planes in my workshop – they are somewhat overbuilt. Due to the fact that they are in the walls, making aesthetically pleasing joinery is not a problem – it won’t be seen. Like the walnut shelves I’m making in the bathroom – in inconspicuous places where joints are hidden, I don’t need dovetails, and I loath 45º mitres. So  five years ago when I was building the myriad of doors in my 6′ high basement I bought a DowelMax.


Fig 1: Shelves made using DowelMax

Miller Dowel System

Prior to the DowelMax, I bought the Miller Dowel System – which is a clever system which works well in certain applications. This system relies on stepped dowels and a hole drilled from the outside, i.e. the end of the dowel is exposed – and herein lies the caveat: as the dowels are shaped lengthwise with the grain (to increase their strength), when the dowel is inserted into the hole and trimmed flush (after allowing the glue to dry of course), the resulting “plug” is end-grain. This doesn’t present a problem in situations where the wood will be painted, or stained (or less noticeable in walnut), but in maple the dowel ends become quite prominent. I still use them, but in situations where showing the dowel end can be used aesthetically, or is hidden (e.g. by books). At C$8-14 for 40 small dowels (2 5/8″), they aren’t exactly cheap either.


Fig 2: The Miller dowel system

DowelMax – what’s in the box

The DowelMax kit I bought is pretty comprehensive (they don’t sell this particular kit anymore). The standard jig set-up shown in the left of Fig.3, works for 3/4″ boards – the spacers allow for boards of different thickness, e.g. add the 3/4″ spacer for a 1-1/2″ thick board (nominal 2″). The index pin allows for multiple holes along a boards length by moving the jig and setting the pin in the end collar. Similarly, the distance gauge can be used to maker larger spaces between holes. By modifying the position of the components on the jig, holes can be placed on the surface, or end of a board. The L-bracket allows for making dowel holes along the surface of a board in a T-type configuration, e.g. for shelves. All the parts are precision engineered, and after five years of use show little in the way of wear.


Fig 3: DowelMax bits and pieces

DowelMax – how well does it work?

I use my DowelMax to do butt-joints. In utilitarian cabinet making, not much else is needed. Yeah I love dovetails too – but they take time, and in instances where the joint is not visible, does it really matter? So number one use – joints where I won’t see the joint, or where the joint is nice enough that it doesn’t matter – corners, shelves, and attaching frame trim to cabinets. If you have 45º mitre joints on boards that are wide enough, they work well there too. I also use it to make wider boards by joining them on the long side.


Fig 4: The DowelMax in use.

The jig can be reconfigured to multiple arrangements to deal with boards ends/edges or faces (Fig.5).


Fig 5: Setups for end/edge and face dowelling

It is also possible to use the L-bracket to create T-type joints (Fig.6), for example for bookshelves.


Fig 6: L-bracket and index pin

So how well does it work? Incredibly well – as long as, likely any other type of joinery, the joints are well aligned. My one quibble? – It would be nice to have some sort of removable “stop” or tab on the end of the main jig block to make registration of the face of the jig block with the wood face easier (similar to the one on the Viel jig or Joint Genie maybe?). Amazingly, earlier prototypes actually had end stops, but they were removed because they were deemed unnecessary.

Fig 7: The Viel jig

When using the L-bracket to make holes for T-type joint such as a shelf, it can be somewhat challenging to align the jig accurately – and it requires a line 1/8″ below the actual position of the shelf to position the jig (see Fig.8). Also nice would be an improved L-bracket that would register the jig at 90º perpendicular to the edge, *and* clamp it would make this a much easier task.


Fig 8: Using the L-bracket

I have used the jig to build shelves, doors for my basement, window sill/box for the windows in the basement (they are 12″ deep), and book doors (i.e. bookshelves that function as doors to closets). I’ve never had issues with it apart from the odd misalignment, which isn’t the end of the world.

The dowels and drill bits

I tend to use the expansible dowel pins sold by Lee Valley and manufactured by JustJoinery, known as “The Pin With a Memory”. The drill bit that comes with the 3/8″ system works extremely well, allowing the pins to be test-fitted (the drill is actually 9.7mm). Recently I decided to augment the system by having one drill bit for the 1½” dowels and another for the 1″ dowels – this is way easier than changing the stop-collar. In cases where a butt joint is made of a ¾” stock, then I tend to use 1½” dowels, with ½” set in the side of the board, and 1″ set in the end of the board.


Fig 9: Dowels and drills

I bought a 3/8″ HSS brad point drill from Lee valley and a set of stop-collars. This drill is marginally smaller than the one supplied with the DowelMax, and so makes it more challenging to remove dowels after test-fitting. This drill is actually the equivalent of 9.525mm, hence the tighter fit. Dowel holes should also be slightly longer than is needed. However on the up-side, the brad-point makes it easier to drill in end-grain. Fig.10 shows four dowel-pins in a 6″ board, and a cross-section through a dowel-pin used to edge-join two boards.


Fig 10: The dowel pins

Don’t use too much glue – it will squeeze out of the spirals.

How strong are the dowels?

A number of studies have looked at the strength of the DowelMax joints in comparison to other joints – and the strength of the joints made using DowelMax are better than many systems. Here is a link to the testing on the DowelMax website. Issue 219 of the British magazine Furniture and Cabinet Maker also has an analysis of six joint types. Here are the results with respect to the PSI value where the joint failed.

Biscuit 180
Domino 400
Mortise and tenon 420
Pocket hole 280
Zeta P2 system 180
Dowelmax dowel system 680

Final thoughts

Overall it’s a great jig, however there are now competitors in the market place that offer more in the way of functionality – they require the use of external clamps, but offer more in the way of alignment. The DowelMax is expensive – but consider the time involved in doing it any other way. You could pay more for a Festool Domino, but unless you have a cabinet shop, it may not be worth the investment. Sadly, the DowelMax is no longer made in Canada (and there is a long thread discussing this on the Canadian Woodworking forums if you are interested). The standard kit is now US$249 – I paid C$325, which included the L-bracket (now US$15), and a ¼” spacer (now replaced by 1/8″ spacers at US$8.50 a piece).

What about the JessEm? Well, I have been thinking about a ¼” / ½” dowelling assembly, so I might just get one of these to try out as well sometime in the future. They also have a cool looking Mortise Mill.


Split-depth collars for drills (imperial) – Lee Valley
Expansible dowels – Lee Valley (3/8″ x 1-1/2″ – C$6.90 for 100). These are the ones for the 9.7mm drills. You can also buy them direct from JustJoinery. They sell the same set for C$5.80, but also sell them in sets of 1000 for C$53.90 (they sell the standard 3/8″ dowels as well). There is somewhat more selection at the JustJoinery site, as they also sell 3/8″ dowels 1-1/4″ and 3″ in length. Also if you are looking for beefier dowels, they have them in 1/2″ and 5/8″ diameters. (The JessEm handles 1/2″ dowels).


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