A muselaar is basically a box. The Ruckers workshop made an open frame, and then glued and pegged the base on afterwards, but this method required more space than many of us have, so this one started with the base, and the rest of the structure is built up on it.
There are no complex joints: the corners are plain mitres. but these and most of the other joints are pegged with trenails.
These are square-sectioned, about 4 mm. When driven into a 4 mm round hole with a dab of glue, they add considerable strength and stability. Literally square pegs in round holes.
They do also offer the possibility of using the pre-drilled holes with screws and protective washers as an alternative to clamping. The screws remain in place until the glue has set, when they are replaced by the trenails, then finished flush.
The case will be painted, of course - the technique is not suitable for unpainted cases, unless they are to be veneered.
In the picture above, the basic structure is complete, with the liners to take the soundboard, the wrestplank at the right, and the diagonal register support. Note the post to prevent the projecting angle of the wrestplank from dipping, and the top-edge mouldings which overhang the front boards and nameboard. There is a 1½" wide complex moulding along the lower edge, and the full-length hinged drop-front will fit into the recess in front of this. The pattern of the mouldings was characteristic of the Ruckers workshop. Originally they almost certainly used special moulding-planes, but I have made scratchstock cutters to match. This method takes time, but it is satisfying and peaceful work, and gives a good result.
The rectangular block at the left-hand end of the register support will strengthen the soundboard for the jack-rail mounting-block.
In the picture above, the keyframe is in postion, and we see the blocks fitted to the spine to hold it in place. The picture also shows the lower guide for the jacks. This is copied from the slots in the soundboard (see next section) but is inverted, with the leather at the bottom and the slots chamfered so that they are wider on the top surface: the jacks must be a close fit in the guide, and this makes inserting them considerably easier!