24 August 2011

Horizontal mortiser

My favorite woodworking machine is the horizontal mortiser.

It is quite,  with 3000 maybe 3600 rpm it is a lot slower than a router.   Powerful, 3 hp for the model displayed.  Due to its low speed it produces limited amounts of fine dust.  Precise, the depth is set to the front of the workpiece where in a drill press the bottom is the reference.  Also precise when making frames as the frame front is locked down to the table giving predictable alignment.  Goes straight, where a hollow chisel keeps it (mis)direction,  the drill is free to realign itself after being pushed sideway by an irregularity.  ROUNDED mortises?  True, these look very machine made, but ... in engineering holes must have rounded corners to avoid excessive stress.

Drilling a mortise with a horizontal mortiser can be done in a succession of: drilling the two extremities, adding free standing holes in between,  drilling extra joining holes,  and finishing with shallow sideway passes.  Personally I prefer a two handle system, where one hand is used for positioning and the other for  movement, keeping at the same time both hands away from the drill.

It is possible to make tenons with handtools (a saw) and straighten up  mistakes when in excess (mainly a router plane).  Where for mortises the process is mostly more brutal and it is more difficult to see and correct mistakes. So, it allows to say: give me perfect mortises,  I will try to deliver appropriate tenons even using only handtools.

Do I need one?  No, only if I was a regular tenon and mortise guy,  or if I was looking for a possibly cheaper or beefier loose tenons alternative to a Festool Domino thing.  The model on the top picture shows a doweling indexing system,  the black tube under the x-y table. But it is unclear to me how to drill in panel fronts.  Speed wise,  based on William Thomas evaluation, I think that longer positioning time gives it half the speed of hand held free tenon alternatives, be it a biscuit joiner, the Mafell Duo-Dowel or the Festool Domino.

Its origins?  I always imagine it is a logical add on to a jointer-planer.  The drill head is an extension of the cutter head.  And the x-y table can be directly attached to the internal planer table,  or like in this example has its own raising mechanism.  Of course it is a fight between space and comfort, where more comfortable is when the table stands on the back of the jointer.

I have an example of simple bed probably made by a finish carpenter around 1930. Pictured leaning against a wall during transport - hence the leaves, to catch the chiseled pairing markings. The joints show that the workshop used a horizontal mortiser.

Matthias Wandel at Woodgears,  made its own horizontal mortiser using a (noisy) router, drawer slides, and some wood. Why buy one, when it is so 'easy' to make one.