Friday, September 14, 2018

Curio Cabinet, Part 1: The Door Joinery

I've been planning a curio cabinet for my wife and have a lot of design choices to make.
The concept - approx 19 x 15 x 5 1/4
This post is specifically about the door joinery.  Here are the limitations.  If the rails and stiles are too wide, then they hinder seeing what's inside the cabinet.  This resulted in the decision for an overlay door, rather than inset.  I settled on 1 1/4" width, which is a bit narrow for door parts.  The frame needs to be strong enough to hold the weight of a glass panel.  The joinery options in this post both have the glass housed in 1/4" deep grooves in the rails and stiles, and the grooves diminish the size of a mortise and tenon.  A complicating factor is the decorative bead I want to put on the inside of the door frame.

The remainder of this post will show the two options I'm considering and I'll go through the layout of the joints for a lower left corner.  I'll also discuss some relative merits of the joints.
First option: a mitered joint with tenon and bridle mortise
Start with squared stock 3/4" thick, 1 1/4" wide
Rail marked out, including 1/4" x 1/4" groove, miter and tenon
After cutting the groove and bead, and showing the waste areas
After cutting and paring away the waste, checking the shoulders and paring them to 90°.
I really cut away the waste later, after using the rail to help mark out the stile (see below).
I've never had confidence in angled layouts.  Knifing a 45° miter on one face, then squaring that line to an adjacent edge is iffy.  Then making  the other 45° line on the opposite face, I never know for sure that my two 45° layout lines are at the same level and that my shoulders will be co-planer.
Marking the stile: first part is not too tough - just a 45° miter
But the outside edge needs the mortise layout and don't know where to lay out the upper extreme
Stile with waste marked
Then cut and checked for 45°
And checking the miter cut is square across the thickness
Mark the mitered surface and the outside edge for the mortise - but how high up that edge?
Turn the stile around so outside edge buts up against the rail.  Then mark the bottom
of the groove recess onto the stile (would be better to mark with a chisel or knife, if one will fit)
Remove the waste and there's your joint
The joint assembled
The second type of joint only miters the inside 1/4" (roughly) of the rail and stile and has a straight tenon going into a bridle-type mortise.
This joint probably has a name, but I don't know it
Showing the part that gets mitered
The layout has its challenges, and so does the cutting.
Can start by setting a gauge to the width of the component ...
... and using that to mark the inside edge of each part
(could also simply mark one piece from the other, since they're the same width)
Also need to get the measurement of the extreme of the bead to transfer to the back side.
Mine was a few hairs north of 1/4"
That distance will mark the waste
The inside edge of the rail is marked similarly, but the question is how to get the extent of the tenon
I did this by cutting away the waste, then setting a gauge to the remaining width
Then using that to mark the outside edge of the components
Then I lay out the mortise and tenon walls and mark the waste
Showing the outside edges marked (ignore the miter lines)
Then cut and pare carefully for a good fit, but ...
... I had only cut close to the miter line earlier.  Now it's time to fine tune.
Made this miter paring jig very precisely
The jig in use, paring tiny bits of the mitered section of the joint ...
... sneaking up on a decent fit
A view from lower left
The layout of these two joints is a little tricky and cutting them can be challenging.  The first joint has only half the glue surface of the second joint.  But even just dry fitted, the first joint felt pretty strong.  And the first joint is a bit easier to cut than the second.
The tenons of each type of joint
The two joints
I like the look of the first joint better.  But I had wanted for quite a while to try the second type.  One difficult thing about the second joint is trying to level and square the part of the inside edge left after cutting away about 1/4".  This is especially important on the stile and can only be done by paring carefully.

Having done these practice joints, I'm more confident going into this build.  But I'm also thinking of scrapping them altogether in favor of a rabbeted frame.  With the two joint styles above, I'd have to install the glass when gluing up the frame.  It would be much easier to place the glass in a rabbet in the back of the frame.  I'm going to look into that next.

To be continued ...