Friday, January 27, 2017

A Ming-Inspired Cabinet (84)

Work on the bifold doors for the two cabinets continues. I realized in the past while that these doors will be the last sets of mortise and tenons to tackle on this project, a point which has certainly been long in the making. Something to savor.

After a spell of fitting work connecting rails to stiles, I had a set of 4 door frame 'ladders' for one cabinet together. Before moving on to fitting the panels and upper/lower rails to those frames, I wanted to be certain that I had the door widths correct. While there is a designed specific door width, errors do accrue as assemblies are brought together, and there isn't a lot of wiggle room between doors with overly large gaps between (i.e., the doors are too narrow) or which are too wide and will not close. Of the two, the latter is to be preferred as an initial outcome of course, however I did not want to be in a position of having to shave significant amounts of material off of the door sides after they were put together for good. It was preferable at this juncture to make any adjustments in that direction by decreasing the shoulder-to-should distance with the door rails, and then to construct the top and bottom rails to suit any adjustments which had to be made.

In what seemed like half a lifetime ago, I had put together the cabinet carcases. While I often rely upon a caliper for measuring where possible, in the case of each carcase the width was too great for any caliper I have, so I had to make do with a measuring tape to layout and produce the desired 51.25" carcase width. I know from working with calipers and the DRO on my mill that rules and, more particularly, measuring tapes, are not the most accurate devices. Many times I have laid something out with pencil and Incra rule, where there are machined 0.5mm dots for each pencil position built right in, and found later via the milling machine's DRO, and later checking the same dimension with a caliper, that the Incra ruler layout was not as accurate as I had hoped. With a regular rule or tape the problem is even worse though in that errors of parallax can also creep in. Regardless, after the cabinet carcases were glued up, I checked by measuring tape and found them to be 51.25" wide, but of course realizing that the number had inherent imprecision. There was a +/- of 0.01~0.02" there, and while that might seem slight, it's also about the amount of space required for door clearance, and if I strayed too far, with cumulative errors say to 0.03~0.04", then the gap would be too large for my liking. If I was to be out on my dimensions, I could hope that I wouldn't be out in the direction of the doors being too narrow and therefore gappy. Looking for slightly fat doors....

With the door frames assembled, given that the rail tenons protruded at this stage, I couldn't simply lay the doors down on the carcase and see if everything fit. The rail tenon portions sticking out kept the stiles from coming together against one another. So, in order to check, I decided that I needed to get an accurate measure of each half of the cabinet, to match with a given bifold door assembly, and then I could measure the doors separately, add up the numbers, and see if they were going to be a close fit or not.

To obtain a measure of half the cabinet width, I used the sliding table saw and an end stop with screw adjuster to cut a pair of matched sticks until they fit end to end across the cabinet:


I made two sets of these gages, so as to account for any possible variation in the cabinet width at top or bottom.

The cabinet was nominally 51.25" wide, or 1301.75mm. Divide that in half, and you obtain 25.625", or 650.875mm.

I was very pleased to find that the carcase half-width at the bottom was pretty much right on the money at 650.9mm:


At top, the width was only very slightly larger, at 651.00mm:


Now to check the doors themselves to se how they compare to their openings. I happen to have a 1meter long Mitutoyo Digimatic, something I picked up used, and at a reasonable price, from Germany at the time I acquired the Zimmermann milling machine:


It comes in handy at times for sure.

So, the half-opening width was 650.9 or 651.0mm, depending. I measured the left side door of the left half bifold at 325.43mm, and the right side at 325.56mm, which adds up to 650.99mm. I was stoked! That made my day. I kinda started geeking out at getting such a close-to-target result and even called my wife up at work to tell her about it. Yeah, yeah, she has learned to put up with my eccentricities for sure, not simply humoring me in such matters but really getting the significance and meaning of such things for me. That's nice.

Anyway, I figure after finish planing of the rails that I will be fine with current rail shoulder-to-shoulder distances, and could therefore move on with further cut out.

One of those tasks was processing the housings for the tenon haunches on the top and bottoms of the stiles. Here, I am starting that cut on one of the hinge stiles:


One of the aspects to the milling machine I have come to really appreciate is the slotted table, upon which one can clamp stuff down so the stock just doesn't move anywhere. It makes the cuts chatter free and clean, and there are no problems with the work wiggling loose while cutting and the associated sorts of disasters that can eventuate with that scenario. I have made many wood and MDF fixtures over the years, and a typical weakness with those fixtures is that the act of clamping the stock to the fixture often deforms the fixture itself, leading to cut out errors. With the mill, the thick cast iron table is not really deforming to any significant degree when I lock stuff down, which improves the final product in some concrete ways.

This is a one-pass cut:


Result:


As I completed the ladders, I laid them out on their respective boxes:


Set #2:


Next up were the top/bottom rails, which are formed in an 'L'-section like the stiles. Task #1 was to mill the dadoes for the panels. Given the 'L'-sections, and position of the groove, the mill seemed the best suited and safest for the task:


Climb cutting made for zero tear out in grooving.

Once the dadoes were done, I moved onto tenoning - these are the very last tenons cuts on the project I do believe:


At this juncture, the tenons are complete on one face and shoulder, and rough cut on the other face and shoulder:


Another view:


One more for good luck:


Next time I'm in the shop, I'll complete the tenons, which are halved and haunched as well, and move onto fitting these rails to the stiles.

Thanks for visiting the Carpentry Way. Post 85 follows.

Tuesday, January 24, 2017

A Ming-Inspired Cabinet (83)

At last I am dug into the work on the bifold doors, the last construction step in this extended build. With two cabinets, that means 8 frame and panel doors to construct. Some of the parts for this, like the panels, were milled and taken to near-finish many months ago. The hinge stiles were milled 3 or 4 months back. Some parts are more recent productions, but in all cases, I have taken my time to work the parts down to dimension in stages, wanting the pieces as straight and square as possible.

At this juncture, I have all of the parts for these doors in some stage of cut out. As usual, working without a net in terms of having no spare parts.

The stiles, for example, are processed to shape, length, and dimensions, and have been mortised:


These mortises are off the hollow chisel mortiser, deliberately cut undersize (using a 5mm hollow chisel) so I can clean them out afterwards on the pattern mill with a 1/4" (6.35mm) bit:


The two step approach avoids the unpleasant outcome, more common with the smallest hollow chisels, of the auger wandering slightly in the cut and causing a mortise with little round marks on the side walls. As these are through tenoned, many of them will show, doors open or closed, and I want the mortises to be free of any glitches, so I mortise in two steps rather than one.

The hinge stiles and hanging stiles are all in 'L' sections:


The 'L' form allows for good support at the mortises for the rails, and keeps the exposed frames quite slender on the front viewing aspect, which then allows for a maximum visual impact as far as the panels are concerned.

After opening the mortises to size on the mill, some chisel work is then required to clean out any remaining bits and produce the completed mortises. Then it is time to fit the rails, which were tenoned several weeks back.

Here's the first door ladder frame assembly:


Another view:


At this point the tenons are proud and un-wedged. Later the mortises will be flared, wedges driven in, and the ends trimmed flush.

Another look:


At this juncture, 3 ladder frames are done, and another day or so should see me to the completion of that work. Then the panels need their many dovetail trenches and the top and bottom rails will need to be tackled. One thing at a time....

While working on the doors, I am moving the shelf parts through finishing:


I have to be careful not to dribble any finish onto the end grain portions of the miters.


Frame and panel work is certainly more difficult to finish than other forms of construction. You can't just spray the assembly with finish, as is so common these days, and once the parts are assembled additional finishing will be required, great care taken not to dribble finish into the expansion gaps for the panels.

The shop remains quite cold, but humidity is low, so the finish dries pretty quick. Still, I am doing just one coat a day, letting the finish get just that little bit harder before sanding between coats.

Onward and upward. Thanks for visiting the Carpentry way - hope you enjoyed your time here. Post 84 follows.

Thursday, January 19, 2017

A Ming-Inspired Cabinet (82)

Nothing but chisel work huddled next to a heater for the past couple of days, getting the trenches cut for the shachi-sen. At last, today, they are all done, along with the pins themselves:


The pins are not driven in yet of course.

Another view:


Afterwards, while routing the dado for the shelf panel in a rail, I unexpectedly had a chunk of bubinga blow out:


It's not a visible area unless one takes the shelf out and flips it upside down for inspection, however I patched the area anyway (forgot to take pictures too). All the rest of the dadoes were done by climb-cutting, so there were no further problems.

Just for a look see, I slipped a frame assembly into a cabinet:


With the shachi-sen untrimmed and protruding, of course the frame cannot slip all the way back into position, and a notch is required on one side to clear the backing strip at the carcase side besides. Soon enough....

These shelves will have a more interesting front edge to view, once the pins are trimmed flush, than the previous slab shelves:



Panels have also be trimmed to size, rebated for a tongue all around, and are entering the phase of the second coat of finish:


All for this round. I should be done the shelves in the next day or two and can at last turn to finishing up the final construction phase, namely the bifold doors.  Post 83 is next.

Tuesday, January 17, 2017

A Ming-Inspired Cabinet (81)

Continuing on with the work on the shelf frames. After cutting out the tenoned joint halves on the mill, all that remained were the open mortised joint halves, also cut on the mill. I didn't take any step-by-step photos of that process, being a bit excited to see the outcome. There were a few tricks to the process, but I wanted to know if the method I had come up with on the mill would produce parts which required little or no final fitting work, so I just kept cuttin'.

Here then are the freshly milled joints on the long rails:



Those slots could have been cut completely cleanly had I possessed a flat-toothed rip blade for my tablesaw, or an appropriate dado/slotting head for my shaper. Those items are on the shopping list.

Instead, I mortised the end wall with my hollow chisel mortiser, using a slightly undersize bit, and then took my ATB rip blade up close to the end wall. It did the job.

Just a little chisel clean-out was required at the root of the open mortise:


Followed  by a pass or two with a Magicut file:


Bubinga is sufficiently hard that metalworking files are suitable at times.

Cutting of this joint primarily by milling machine seemed like a good idea, and I took pains with my set ups and fixturing - not that improvements couldn't be made for next time (duly noted) - but there was no way to know the outcome fit-wise until the cut out was entirely complete.

To my delight, he first frame fitted together with no additional work, and the joints were just the right amount of tight:


A look at the four corners, from one side at least:





I thought the outcome proved once again the utility of a pattern mill for joinery work.

A look at a couple of the exposed tenon ends:



I was very pleased with the results, as the other frames came together with a similar lack of fussing around:


On the second one down you can see one the end grain of the tenon the patch which was put in to repair a defect in the stick.

Now then, while much had been gained, much also remained, cut-out wise. The trenches for the shachi sen needed to be laid out and cut. The layout is simple enough (though easy to confuse as well):


For more info on shachi sen mitered joints, you may wish to take a look at my TAJCD Monograph #1, found in the sidebar to the right of the page, which is devoted to that topic.

The lines from the edges were then transferred down faces of the tenons and cut out could commence. Here I am paring against the grain of the cheek face to start, a normally ill-advised move for which I have my reasons:


I got dug in at that point and didn't take another photo until I was complete through the first corner. While cutting the trenches on the tenons isn't too bad, given that one can push a chisel from either side, the trenches inside the open mortise walls were another matter. These have only 0.3125" of height, for starters, and they are blind as well, and they against the grain down the face. I find them among the most difficult sort of things to cut.

The first one came out like this:


With curly bubinga a bit of chip out, as you can see at the left side of the lower trench, is hard to avoid. It was nice, in a way, to be reminded of that with the first joint corners. I will be be able to correct that fortunately.

After a couple more hours, I was through the first three corners of the first frame. That leaves 13 corners to complete, albeit only the open mortise halves of the joints need tackling as the trenches on the tenons are all done. It's likely to take another day in the shop to get through that lot, and then I will make the shachi sen (wedging pins) and fit them. Then the shelves get fitted, and notched for the shelf pins, before finish planing and finishing can commence.

All for this round - thanks for visiting. Comments/questions always welcome. Post 82 is up next.

Friday, January 13, 2017

A Ming-Inspired Cabinet (80)

Click here for a the previous post.

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During the interim in which I constructed and installed the Japanese ceiling, I moved the cabinets along in a couple of minor ways. I have been applying patination to the bifold door hinges, still in progress, and contracted with a local machine shop for the fabrication of hardware for the bifold door main hinging.

One thing did crop up while the woodwork for this cabinet sat, and that is a problem with the four plank shelves, three of which cupped. I guess that's one advantage of proceeding slowly with a build, you get to see certain outcomes that otherwise would have occurred after the piece had been delivered to the client. Given the choice, I'd much rather the problem occur while the piece was still in my possession of course.

I took precautions, as usual, when dimensioning stock down to make those shelves, jointing and planing over several days, balancing stock removal on both sides of the blank, etc., and after applying 4 or 5 coats of finish to both sides, they were flat. Several weeks go by, and they had moved out of flat to an unacceptable degree. The cause, given that bubinga is generally a decently stable material, particularly when in quartered-to-rift grain orientation, as these shelves were, lays either in how the material was originally dried, or possibly in growth stresses in the tree that were slow to manifest. I tend to think it was mostly attributable to the drying, and therefore I won't be buying bubinga from that supplier any longer.

It goes to show as well that solid plank construction is going to allow for a greater amount of movement than frame and panel construction. There's a reason you don't see much of it in the classic Chinese work. This aspect - the advantage of frame and panel over other methods -has always been quite clear to me, however I had thought that maybe for shelves it would be okay. In fact, making 3/4" (19mm) thick shelves at 17.5" width out of single boards might in most circles be considered quite luxurious as a use of material.

No such luck though, so I am fabricating new shelves and these ones will be, you guessed it, frame and panel.

I sliced up the original shelves, jointed and planed them down, so as to form panels:


That took next to no time at all, as they are 'merely' quartersawn bubinga.

For the frames, I had but little extra material from which to choose. In fact, all I had was a remnant flatsawn chunk from the middle of the original 16'x 52" x 3" slab that had jump-started this project many moons ago. While I have little use for flatsawn stock generally, by resawing this piece lengthwise I was able to obtain 4 sticks of perfectly quartersawn curly bubinga.

Curly bubinga was a harmonious match for the material used for the two principal horizontal frame and panel assemblies in this cabinet, which lie above and below the shelves themselves, so from that perspective curly bubinga was an excellent choice. What made it a less than scintillating choice however, was the fact that as curly material, normal jointing and planing was only going to get me so close to dimension, lest I risk too much tear out, and that meant that my milling machine was going to be the route for getting to finish dimension.

That meant that basic dimensioning was going to take a couple of days, not 15~20 minutes.

There's something about having made well-fitted shelves, and then applied many coats of finish to a pleasing result, only to have to start all over again, and to boot be employing a different material and form of construction which was going to add many days of work. I had thought I would be moving into final stages with the door framing  - instead I take a step back and work on shelves again. I thought it over long and hard before committing to this course. I was initially a little grumpy about the extra work, however I am more than happy too knowing that the result will be better than previous. And that is what it is all about for me and my woodworking: a continuous striving for improvement.

So, on with the stock prep, day one comprising the resawing, jointing, planing and that left me with decently clean stock, albeit a little tear out here and there:


The stock is sufficiently oversize that the tear out is of no concern.

Then first pass with the milling machine on all the long sides of each of the 16 sticks:


I'm using a CMT top bearing bit with negative rake teeth, which all but ensures zero tear out.


Now working the edges:


 In my humble opinion, so long as you are producing chips and not dust, all is good with the world:


After round 1, I had the sticks good and square - you can always get a sense of that by how well they stack next to one another:


Notice on the far right of the pile that there is a defect there. I had to patch that area, as I simply have gone through absolutely all of my curly stock. As with many other stages of this job, i have no spare sticks to work with, so layout and cut-out mistakes must be avoided at all costs.

During the first day of action with the milling machine, cutting left to right to left to right..., I noticed towards the afternoon a certain odd noise start to develop with the machine. This noise grew worse over time and it associated to the power feed. Every time I shifted direction, the noise intensified. I started to get this feeling of dread come over me, akin to the feeling you get when you start to apprehend something is decidedly wrong with the internals of your car's engine. As anyone with experience knows, you don't pull an engine out of a car and strip it all apart just to replace a single valve, or pushrod seal, or piston ring. When you take an engine apart, it is generally wise to rebuild the whole thing. It's cheaper in the long run.

I was worried that the gearbox on my Zimmermann mill was developing problems. That's sure what it sounded like, and I could see that to get at the gear box was not a simple job, and may even mean stripping the mill down just to get at it. Besides the timing being lousy for this, I am not in a position to have the mill down for long periods, let alone pour money into it.

I didn't sleep well last night, and was feeling a bit on the mopey side when I went to the shop this morning. I was fearing the worst, but I hoped, with another round of dimensioning to do on the mill that the gearbox would at least do me a favor and hang in there until the task was done.

The next day I started milling, and sure enough the noise was there right away. I couldn't seemingly wish it away after all.

But this time I got in a little closer with my head to the gearbox to see if I could more precisely localize the sound, and discovered, to my considerable delight, that the noise wasn't coming from the gearbox after all, but from the motor and pulley drive set up on the outside of the gearbox. I removed some allen cap screws and got the motor cover off, and sure enough I found the culprit: the motor's drive pulley was coming loose. Whew! That was good news indeed.

Curiously, the square key which ties the pulley and motor output shaft together was absent. I'm not sure if it was missing from previous repair or whether it had simply come out at some point and worked its way past the cover and to the floor (somehow). Whatever the case, a new square key and set screw were needed, so off to the local hardware store I went. Now, the correct size key was 5mm x 5mm, 25mm, however, this is the US after all and selection of metric parts remains less than optimal at most hardware stores. As expected, they had no metric square keys. I was able to find 3/16" (4.76mm) square, 1" (25.4mm) long key stock, so that would have to do in the meantime. Better than nothing.

I fitted the square key and new set screw to the pulley, and put things back in order. It worked, but not silently, and after a while started getting noisy again. I took it apart again and realized that after the old key had fallen out or been lost, and the pulley gradually worked its way loose by grinding the set screw away, that the inner bore of the pulley had been sufficiently worn to now be a poor fit. Correcting the problem, however was, at best, a job for a machine shop. I wasn't interested in yet another delay however, so I improvised, taking a plastic dado set shim, wrapping it around the motor output shaft, and then slipping the pulley back on over top:


Surprisingly, this worked like a charm! The pulley spins without wobble or any noise, stays put, and all is well.

Now, I'm not the sort who leaves a 'spit and bubblegum' type of repair, as this one surely is, until it next fails. I'll be taking that pulley to the machine shop soon enough and get it properly repaired, but for the interim, my mill will be usable and I can get the job done.

Round 2 of milling could then  proceed, and a whole lot more quietly I might add. Here, after having worked all the broad long faces, I am gang-cutting the edges of half of the short pieces:



They were done after not too long:


The stock is about as square as can be, and within a few thousands of dimension in every axis. I'm always pleased to obtain results like that - it's like putting the dart into the bullseye when you actually meant to do so....

The frame stock now prepared, it was time to turn to the joinery work. Options abound for corner joints. I'm going with a form of mitered, tongued, and tenoned corner joint with shachi sen. I last did this variation of that joint on a Walnut Vanity I made about 10 years ago (link), in that case with both a tabletop frame containing a tongued panel, as well as the support frame below it.

I've cut this type of joint in myriad ways, and this time I decided to have a go with my mill. I thought it might offer some advantages, although if I had certain (other) tooling on hand, a preferable choice might be to process the joints partly on the shaper's sliding table. You work with what you got, be it hand tools, or sliding saws, or sliding shapers, or milling machines. I lucky enough to have all of those pieces of gear and decided try the mill this time, and meanwhile dream about what sort of shaper tooling I'd like to acquire sometime down the line....

Here's the jig I came up with on the milling table:


A couple of screw adjusters allow for fine control of position, and the slotted table and beefy hold downs mean that the material is securely held:


So here's a rough step-by step accounting of how I processed the cuts on the tenoned sticks. First, I ripped the cheeks using a quick-built MDF jig of scraps on the table saw:



That left the following result on both ends of the short sticks:


Then the chop saw, with depth stop engaged, to trim the waste off the miters:


Though both table saw and miter saw could have been used to go to a finial surface with those same cuts, I don't rely upon those tools for that in this case, I merely rough out with them.

After the chop saw work is done, the mitered tenons are defined, but not yet to their lines:


Then into the mill with the same pieces.

After having taken some time to calibrate the cut on a test stick, and I deck the tenon cheek and trim the mitered shoulder in one set of passes:



The stick is then flipped around to the other side of the jig and the process repeated on the other side, with the slight difference of using a climb cut on the abutment.

Result is a tenon within a few thou of dimension for thickness and with cleanly cut mitered abutments in a common plane:


The process was repeated until both ends of all the short sticks was brought to the same stage.

The next step, using the same fixturing set up in the mill but with a different cutter, was to cut dadoes on the mitered abutments. That required a change of tool holder, to a slimmer unit which accepts ER32 collets:


I also trimmed down the positioning blocks to clear the collet nut. Again, a few cuts were necessary to calibrate the cut depth, and after that the processing could proceed fairly rapidly.

That said, at the end of today's session, I had just the one stick through the dado-ing stage, and the rest lined up and ready to go:


It shouldn't take more than 15 minutes to complete the rest of the dadoes on all those sticks.

A last look at the dados and mitered abutments, all cut fairly cleanly it seems to me:


So far this method of cutting with the mill seems to be working well. The proof of the pudding, of course, will come when the mating piece is done, whereupon I am looking to obtain fits without having to spend time fettling the joints. We'll see....

Thanks for visiting the Carpentry Way. The 81st post is next.