Monday, August 29, 2016

A Ming-Inspired Cabinet (71)

I got a couple of good sessions in over the weekend and moved the bonnet for the second cabinet ahead to the same point as shown in the previous post.

Today's task was to fabricate the stub posts, tsuka, for the two cabinets, and...well, let's just forget the 'and' part because it never happened. I often have a list with several 'ands' in it, but things don't always go as quickly as one might hope. There were a lot of steps to making these little posts.

These little posts are only 1.0" square in size, and I have rough milled the parts last week. It's a bit of a pain to try and joint such little tiny sticks on the jointer, so I squared them up in the mill. It was slower, but safer and super precise.

Then I milled dadoes on two sides of the post to fit around the shedua stand off boards:

After the dadoes were cut, I used the mill again to process a coved cut on the outer arris, then trimmed the parts to length:

There are four pieces here, in case it wasn't clear:

A few steps later, I had the tenons cut on both ends and the chamfering complete on all 8 pieces:

Another view:

Fitting could then commence:

The end panels slide down between the posts:

Posts fitted to one half of one assembly:

I then repeated the process of fitting the posts to the other half of that frame 'sandwich'. That task complete, I could put the two halves together:


On to frame #2:


The bonnets temporarily situated in position for a look-see:

Another view:

Another view:

Next round I plan to deal with the mechanism to attach the bonnet to the top of the carcase. Hope to see you again then. Thanks for visiting the Carpentry Way. Post 72 is next.

Friday, August 26, 2016

A Ming-Inspired Cabinet (70)

Holy cow! 70 posts. How many months have passed? Ocean-going ships have been built and launched in the same time frame I'm sure, probably entire subdivisions of houses stapled together. Yes, this is a journal of a failed cabinetmaker, someone who took too long.

It's hardly some sort of contest, but this is a long project, and I'd like to say I'm enjoying every minute of the process even if I sometimes think it is friggin' endless. Sure, sometimes things go awry and I curse those capricious gods, but overall, it's all about bringing something together which has been carefully thought out and planned, a matter of taking steps forward in determined fashion. And even with the planning, a certain portion is left to unfold organically. You can stare at a CAD drawing all day, but nothing informs like the object sitting in front of you. Still not totally certain how it will all come out and I'm fine with that. I hope you're okay with that too.

The overall trajectory is satisfactory as far as I am concerned, and the client has been very supportive and patient too, which cannot be understated as being critical to what has unfolded. Nicest client I've ever had, hands down.

Working now on the bonnet, the top portion of the cabinet which gives some sense of visual termination to what would otherwise be a rectangular box on a splayed stand. Can't have that, now can we?

The bonnet is formed from two bubinga framed assemblies, separated from one another by a shedua stand-off, also mortise and tenoned together, plus some bubinga stub posts, tsuka as they would be termed in Japanese. The lower bubinga frame was done in quartersawn bubinga, while the uppermost frame is done in curly bubinga, aka nightmare wood.

In this way of layering the parts, the pattern already set down at the stand is echoed in reverse, where a curly bubinga framework is surmounted by a quartersawn bubinga cornice. As with the stand, the structural logic of the 'I' beam is brought forth in the bonnet. With the stand the i-beam serves to provide a stiff support to the cabinet's lower board so as to preclude any sagging in that board below all the drawers, while with the bonnet the function of the i-beam is to provide a stiffening element above the top of the carcase, which is a after all a board spanning atop the sliding doors. Making the bonnet framing stiff and anchoring it well to the upper carcase board should mitigate again the upper carcase board sagging downward over time due to gravity, which would cause the sliding action of the doors to bind slightly. Well, it is but a possibility of course, but wherever possible I want to design so that the structure's aesthetics meshes as well as possible with loads as may be envisioned to manifest over the long term.

Template shaping comprises the first step in the process which I wish to share today- though in truth much cut out has already taken place on these parts:

Helical and carbide, plus an Aigner chip collection hood- what's not to like?:

Four upper beams are shaped, and then they are ganged together for a bit of clean up:

The large diameter of the shaper cutter, of course, did not allow for the profile to be fully realized by that template shaping step, so additional work was necessary (on the pattern mill) to define the 'jog-ups':

That was yesterday's news, and the days' previous, it might be noted.

Today I spent most of the shop time fabricating the cross members, and then with the joinery cut it was time to fit the parts together:

"Beat it to fit, paint it match", as they say. Always looking for a bigger hammer and, optimally, a rusty pair of vice grips. How else do you get stuff done?

A closer look at the undersurfaces in union:

The first bonnet assembly is through the phase which could be called rough assembly:

I've left the cross members fat on top as they meet curved surfaces on the rails and cannot be readily processed to shape by themselves:

Those excesses are then relieved through more fixturing and milling work:

My dear friend, Fritz Zimmermann has proven to be stalwart. How's that for a word you don't hear every day?

Curly bubinga gettin' a haircut:

Gradually, pass after pass after p...., the upper surface of the cross piece is brought into a match with the stepped and curved form of the rail:

The first cross piece is completed, at least as far as milling is concerned:

A while later, the second of the pair is milled:

While only two of the four cross pieces are shaped, impatient as I am,  I couldn't resist a look-see of the assembled parts atop the shedua standoff, to see how everything was fitting:

Amazingly, the parts seemed to be going together well. Another lucky day for me. There will be little stub posts to go in those corners soon enough, but, hey, one thing at a time.

All for this round. I'll be back in the shop tomorrow and hope to move these bonnet parts along a bit further yet. Hope the tail end of your summer is coming in smoothly and with a clear-eyed view to the months ahead. Next up: post 71

Thursday, August 18, 2016

A Ming-Inspired Cabinet (69)

The drawers needed some further minor work - trimming the rear floor edges, a process which began on the sliding saw:

A piece of MDF locates the drawer position for the cut and protects the lower arris from blow out when sawing.

The saw cut is then cleaned up by plane:

The drawers have been completed, to the dry-assembly stage, and fitted to both cabinets:

Another view:

Another view:

Next up in the task list are the adjustable height shelves for the cabinets. Originally, I had planned on a pair of shelves each side, however upon further consideration I decided that one shelf each side made more sense, given the depth of the shelves. I decided to set up provision for 7 heights for each of the shelves.

Drilling holes for shelf pins seems like it might be one of those those mundane, low-hanging fruit sort of tasks. In some respects that is true, as, well, how hard is it to drill a bunch of holes? However, each shelf sits on fours pins and if one of those holes is mispositioned, the shelf won't sit flat upon the pins. If a hole is drilled at a cock-eyed angle, the pin will not sit flat to the surface or support the shelf properly. Those outcomes are not the end of the world, as compensations can be made afterwards, however it seems better, to my way of thinking, to put the holes in the right x-y-z  position and correct alignment, from the get-go. The shelf sitting goes a lot smoother afterwards. Drilling holes in precise positions however is not always a simple task in the world of woodworking. At least I have not found it so until very recently.

Now, there are various commercially produced jigs for drilling precision holes for shelf pins. I don't have any of those, but some look quite decent to be sure. It seems though that, unless one makes a fairly standard sort of furniture piece in terms of its adjustable shelve positioning, then the highly varied nature of the beast makes it a bit difficult for a general-purpose jig to suffice for all conditions. So, as I have done many times in the past, I make my own drilling jig to suit.

The mill once again proves its worth for a task like this. After preparing a sandwich of three MDF panels, two thin and one thick, then jointing and squaring them up in ganged fashion, I then screw the layers together, align the contraption to the table's rear fence and fix it down. Once positioning has been set up, I can drill the first hole:

Note the DRO indication shows the second drill position, as I started out at 0.0000 in the y-axis.

Then I zero the y-travel indicator, and drill a series of holes along that axis:

Once those 7 holes are done, I shift the z-axis over by the required distance, 13.5" in this case:

Again, I drill 7 evenly spaced holes along the y-axis, stepping back until 0.0000" has been reached:

That was easy to do and quite accurate I thought.

The jig is then clamped to the cabinet carcase like this:

A secondary block, also drilled on the mill, serves to control the depth of the hole. One doesn't want any errant drill-throughs of the cabinet carcase at this sage, or any stage for that matter.

The holes are drilled and this is the result on that side panel:

The jig is then switched over to the opposite side of the cabinet:

Once both side panels of both cabinets are done, one layer of the drilling jig is removed so it can align properly to the central divider:

The central divider holes are drilled through from one side only, so back up blocks are required to preclude blow-out:

The completed through-holes in the middle divider of one cabinet:

It is worth noting, perhaps, that the design thickness of the central vertical divider, worked out many months ago, was in fact based upon accommodating the length of these pin inserts. It would have been all to easy to simply consider the divider thickness as an aesthetic matter only, and made it, say, 0.625" thick instead of 0.75" thick, however the shelf pin insert controlled this aspect of design. The important thing, I guess, is to see such issue aheads of time, rather than dealing with the repercussions of the oversight of such a seemingly minor item later on.

Once all the holes are done, the 7mm shelf pins can be fitted. I like to use the Lee Valley product, sourced from Italy, which has threaded inserts for each pin. The inserts are fitted using a special tool (no longer available in the 4mm size from LV for some unknown reason):

The instructions specify that the holes be 6.75mm if in softwood, and 7mm if in hardwood. Since the inserts themselves are 7mm in diameter, I thought drilling a 7mm hole would be a bad idea. An interference fit of some sort is desirable, after all. I looked through my drill index set and chose a letter drill, size 'I', which measures 0.272" (6.9mm) nominally. I measured it with my calipers and found it to be a hair under spec, at 6.85mm, which seemed like the perfect size.  I confirmed such by drilling a hole in a block of bubinga and seeing how an insert fitted. All good. Letter size 'I' it would be.

At that hole size, I found the insert could be pressed with the tool most of the way in by hand, the last 10~20% of travel requiring a tap of two with a hammer. Here's the first insert in place:

The tool places the insert just below the wood surface. After all the inserts were in place, I found myself short by 8 inserts, a result of the design change in terms of the number of shelves and shelf hole positions. Another thing I now need to order from Lee Valley.

The back of the shelves required notching at the back on the outsides where the backing strips were located:

I elected to notch the undersurface of the shelf panels so as to house the pins in the shelf, rather than having the shelf sit atop the shelf pins. The reasoning here is that the housings around the pins trap the panel in place forward and back, precluding the chance that the panel could accidentally slide forward and drop down.

I put together a simple jig to rout the notches:

One side is set up so as to rout a narrow notch, for the rearmost pins, and the other side is routed with an elongated notch to accommodate any differences in seasonal movement between the panel and the cabinet carcase:

The rear notch with a pin in place to show the fit:

I used an 8mm spiral carbide bit, which I thought was close to the right size for a 7mm pin.

And here's the elongated notch:

The reason to use two sizes of notch is that the shelf panel can be held to the rear, where it will meet the rear infill panel, and  not open up any gap if the panel were to shrink - all movement happens at the front.

Here's a look at the installed shelf atop the two pins:

A final task was to chamfer the front edges of the shelves:

The upper arris is chamfered 45˚, while the lower arris is given a 3-4-5 triangle bevel (36.869˚) using a specialized plane for such a task:

The 'Isuka' plane. The one seen above is a higher class type with ebony rubbing strips, a detachable sliding blade-holding body, full length brass insert in the sole, and a slightly skewed blade.

Once the pins were fitted to one cabinet, I could fit the shelves:

Another view - both cabinets this time:

The shelves are a full 17.5 inches (444.5mm) in depth, and are generously thick at 0.8125" (20.6mm). The shelves may see a lot of loaded weight, and I don't want them to sag. I will be notching the shelves to sit over the pins, and have a bit of chamfering to do on the lead edges. Otherwise, they are ready to finish.

You may notice also from the above pair of photos that work on the bonnet portion of the cabinets is now underway. That will likely form the focus of the next post in this series.

Thanks for visiting. Post 70 is next, if you think you can stand another one.