Friday, April 14, 2017

A Ming-Inspired Cabinet (92)

Final post in this thread - - just kidding!

Moving along, moving along. Before I could bore out for the hinge bushings on the support stand’s sill, I had to assemble the sill frame together. The corners on the frame are Japanese mitered box joints with shachi sen, and this corner you see next was the first to be done, and incidentally was the one shown in the previous post, with my assurances that the miter gap would be gone once the pin was in place:

I originally had fabricated ebony sen for these corners, however I found upon driving that first one in that it had an internal flaw which lead to it splitting. Not a particularly enjoyable outcome, and it took a good while to extract the split pin sections from the confines of its mortise.

That left the task of making new ones, which I chose to make out of bubinga. One of the problems with ebony is it can often have internal fissures and splits that may not be obvious after cut out is done.

Again, I turned to the milling machine for the task of tapering the pin thickness slightly over its length (about 1/32" over 6" in this case). The sen were affixed onto a piece of aluminum plate with double-sided tape, and the plate itself canted in the vise jaws by way of a feeler gage. The milling went very quickly:

The pins were then made into parallelogram sections and tapered for width using a shoulder plane, and fitted, one by one, to their respective corners and driven home. They will be left long for the time being – maybe for good.

With the bubinga sen installed the hinge bushings could be counterbored and bored. First, a pointer from a Starrett trammel set is chucked up and used to locate the machine spindle directly over the pricked mark:

Then onto the 7/8" Bormax:

A check to see that the bronze flange of the bushing fit the counterbore:

And then the 5/8" hole was bored to about 0.01" over the required depth for the bushing:

It fits!:

I’ve been talking a little bit in the past couple of posts about tool holders and collets, and thought a picture might be informative for some readers. On the left is an ISO40-taper tool holder with ER27 collet (10mm) and Forstner bit, in the middle is an 8mm ER27 collet, and on the right is a 444E collet, which fits, obviously, a larger tool holder:

Quite a size difference between those collets, eh? Of the two, I prefer the 444E, as when you loosen the collet nut the tool tends to stay put in the collet (though it is easy to slide out), while with the ER27, when you loosen the collet nut the tool can, and will, just fall out. That often means traveling down onto the work, making a mark in the surface (ugh!) or a clear perfect fall onto the cast iron table top, thus dinging the tool point or and edge (ugh!). I’ve learned to put a piece of scrap wood under the ER27 collets before loosening the collet nut, thus giving the tool a landing pad of sorts.

The next day I’m back at it on the mill, this time, after the usual preliminary milling steps, forming some ebony blanks into wedges:

This sort of job, for just 8 wedges, can be tackled in various ways, using hand saw and plane, with a jig to hold the wedge in place for planing, or by way of a tapering jig on the table saw or router table. I think the mill is the best way to do it however, as the piece is held absolutely rigidly, and can be milled at the precise angle required, and it is dead safe as your fingers never get near the cutter. Quick too: ll I had to do was cut a slice of MDF at the required slope and fit an aluminum stop into one of the vise jaws and cutting could proceed.

The roughed out wedge, number 1 of 8:

The wedges were taken down in size over a couple of stages.

Later, the wedges could be applied to the ends of the hammerhead draw bar pins, so as to fix the support stand sill to the bottom of the carcase:

At this point the wedges are left just a hair fat, so they don’t enter as far as they ultimately will. They are also over-length:

One side in a closer view:

A while later both cabinets were through to the same stage:

Then the cabinets could be stood up so the bonnet cornice pieces could be fitted on top onto their dovetail keys and slid into position, then bolted:

A cabinet back down again and - what’s this? - some hardware being applied to the upper end of a hinge stile:

At last, the first cabinet has its outer doors (trial) fitted!:

Just a check to show how the door can swing a full 270˚ with the offset hinge rods:

Now, I knew it would make the swing as I had designed it that way in CAD, but sometimes one feels a need to check that it really all works as it should once built., where the virtual meets the real.

The two middle panels could be just squeezed in to the middle, however a little bit of fine tuning will be required as there need to be slight gaps between door leaves:

And here’s the client’s cabinet, through to the same stage:

Another view of the first cabinet with a different camera setting:

I feel a certain milestone was passed today, and feel good about where the project stands. While the doors are not complete by any stretch, the end is in sight and I think I should be able to make the required fitting adjustments and install the hinges for the inner door leaves in the next couple of shop sessions. That will leave only a modest amount of construction work to do, and mostly a bunch of finishing and hardware installation. Nearly there….

Thanks for visiting the Carpentry Way - comments most welcome.

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