Thursday, January 28, 2016

A Ming-Inspired Cabinet (28)

Post 28 in a continuing series, and 900th post since this blog was started back in 2009.

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I got tired of using a screwdriver across the terminals of the otherwise dead start switch on my Zimmermann, and got around to replacing both push buttons and their mounting plate:


The original push buttons were a larger size and in replacing one of them with a 22mm push button operator, I needed to make a new mounting plate, so I ended up getting a new 22mm 'stop' switch as well . The new 'stop' switch is larger and a little easier to hit if you need to shut things down in a hurry. Safety first!

While doing that work, I accidentally grounded a light circuit conductor and blew a 6 amp fuse. The fuses on the Zimmermann are ceramic, a bit like the ones you find in an electric stove, and fortunately I had one spare 6 amp fuse on hand. There are a dozen fuses in the machine and when a fuse blows there is no obvious visual indicator that I can see on the fuses themselves.  You have to test across each one for continuity, which is a little tedious.

Looking in my factory operation manual to dig into the wiring schematics and electrical component specifications, I discovered that the fuses are supposed to be Siemens 'Diazed' 25amp units, however almost all of the ones in the machine are 6amp. That leaves me slightly puzzled. Either the ones in the machine are wrong, or the operations manual (from 1980) is wrong, or for some reason the specification was changed between 1971 and 1980. I also have a wiring diagram from another year, and it is identical to the first one but there isn't an electrical parts list included in the other year's paperwork to confirm which model of fuse was used.

I am wondering then about the correct fuse amperage:  25 or 6A?  They have all been working fine so far, but then again, other than the recent accidental connection, there has been no event which has caused them to be tested. They could be fine and they could also be inadequate. I'm not sure what to do. I'm seeing no reason to change anything, but also wondering if the fuses in place are undersized.

I bought a package of 6amp fuses from Germany, and they were pretty cheap actually, and shipping was less than $10.00. Hopefully they will be here soon as I feel nervous having no back up fuses.

This is where I wish I was a bit savvier about motor electrics, and could possibly work out what the correct fuse size should be. I need to study this more.... I confess I am a little fuzzy in my understanding of momentary switch electrics. I do understand that the starter switch is a normally-OFF circuit, meaning the button push connects the circuit, while the 'stop' switch is normally-ON, and thus pushing the 'stop' button disconnects the circuit.

Motor controls are not direct in the same way a when you turn on a household light switch. There are magnetic controls between the switch and the motor. When the "start" button is pressed, the motor is not powered directly, rather the electromagnet in the contactor is energized. The magnetic switch in the contactor then engages, simultaneously switching current to the motor and providing self-sustaining current to maintain its own state. Thus when the start button is released, the magnetic switch remains engaged and the motor remains running. I find this fact slightly counter-intuitive, but it is rather similar to the use of relays in an automobile. Instead of routing 460volts through the start/stop switching, the power comes from an internal transformer putting out 30 volts. A low voltage circuit controls a high voltage motor.

I spent the past couple of days doing some CAD work, as my car has been in the shop. The client got back to me and is fine with the design revision to change the steps in the middle portion of the cabinet for shelves. He also wants me to devise a system to attach the cabinet mechanically to the wall in case of earthquake. He lives in LA, so this is a reasonable concern of course. I've got some ideas about that and we'll see where things end up.

Last time in the shop, I was trimming leg tops to a double-bevel or compound angle:


The legs only slope 0.5 in 10, so the slope is hard to see in the above picture.

The legs after the compound bevels have been cut on top - a little more obvious to see the bevel now:


The post tops were the tenoned in one axis:


Another view:


 Another view:


Further reductions lay ahead....

Thanks for visiting the Carpentry Way. My car should be fixed this morning so I will be back in the shop as well. On to post 29

Wednesday, January 20, 2016

A Ming-Inspired Cabinet (27)

Before getting to project progress stuff, I guess a few more chisel set pics wouldn't hurt, as the earlier ones shared in the previous post were a bit dark. Hope this gives a clearer view:



The gumi has some nice irregularities, which I like:


The rings are pre-fitted about halfway on, and it did not take long at all to prepare the handle end and drive the ring on:


I fitted 10 rings in a row and it took about 30~40 seconds each. These tools almost set themselves up.

The flat neck allows the chisel to behave like a long paring chisel:


Meanwhile, more legs were being milled on the Zimmermann. The splay on the legs is 0.5 in 10 each way, which is the slightest slope I've worked with when dealing with these type of compound-angled projects. It's challenging.

In this step, the legs and attached bronze leveler foot are being made very slightly out of square in cross section - intentionally so - with but a whisper cut:


There's likely no point in trying to mill such a thin angle, but I thought I would give it a go.

Then the set up was changed and the top of each leg rebated in two directions so as to form a clamping tab:


A minor puzzle to set up:


The clamping nub on the end of the leg:


The c-clamp was tried and then latter found to be unnecessary:


The last couple of days however I've been working a fair bit on the project drawings again, so I haven't been at the shop at all.

As I revisit the drawing time and again I have been allowing the design to percolate. This has proven to be advantageous actually. Some aspects cannot be reversed now as I've already cut the parts, however other aspects - namely much of what will be placed atop the stand I'm currently making - exists in a window of opportunity for change. So I keep thinking about ways the piece could be improved or tweaked.

One area in particular I have been scratching my head on concerns the hardware for the bifold doors. In a past project, the walnut vanity shown back in 2009 on pages here, I overlooked the hardware a bit and it came back to bite me in the ass when I found that the little doors with curved edges were problematic to hinge. I avoided a disaster on that one by slight fiddling with hinge centerlines, but it was a close call and drove home the lesson that sometimes seemingly minor things can have significant effects on a given design. It is all too easy to overlook a minor thing which can in some cases sink a design altogether.

With the bi-fold doors, I have multiple hardware requirements. There are the pivoting hinges, there are the hinges between the door pairs, and there needs to be some means by which the doors can be latched and held, at least in the closed position and possibly in the open position as well. There need to be handles fitted on the front of the bifold door pairs, and these handles should stylistically tie to other hardware if possible.

Intersecting the hardware choices for the bifold doors are the hardware choices for the drawers, along with the set backs for the drawers, drawer dividers and the upper sliding doors as well relative to the back of the bifold doors and their hardware. A certain type of drawer handle, if located in an area where a piece of hardware (like the hinge) for the bifold doors was located, could create a point of interference. That's just one of the potential hazards to be considered.

I was going to go with a piano hinge for the bifold doors, however, strictly speaking the doors are not so heavy or heavily stressed that the piano hinge's strength is especially needed. So I began to consider smaller hinges. Piano hinge quality wasn't all that great for the most part besides.

Then I came across some interesting sprung hinges, made by Bommer. Here's an example:


Between the hinge parts on the upper end you can see a little capstan turret sort of affair. You insert a metal tension rod into the capstan and turn it to add tension to the hinge spring, then move into place a second small pin, into a keeper hole, to keep that tension setting. They are pretty cool, stoutly made and the company has been in business since 1876. They make a small enough model, 3" long, which could work very well I think on this cabinet. They would be largely concealed from view. The springs would work to help the doors close flat and would assist in the process of opening the doors from their folded position.

The thing I want to avoid is a uncontrolled bifold door swinging open all the way or dangling out in space. I want the door to fold away tidily, and store well in both open and closed positions. The bifold doors on the closets in my house use a metal guide track on the lintel, however it makes an unpleasant noise when the doors are opened, and look horrible. That was not an option. For a while I thought of making some sort of wooden track on the cabinet's bonnet support rail, and a sprung pin on top of the doors to follow that track. I think the spring hinges might door the job better, and more quietly, however I don't really know for sure. as a result, I'll do a mock-up and test out a few different combinations of hardware to see what is what. I want the door to feel smooth and well-guided as it is opened and closed, so some experimentation is in order.

A means of latching the doors in the closed position has also been an avenue of investigation recently. I'm leaning at the moment to using a metal ball stud and socket type of catch mechanism:

Receiver left, male threaded ball stud to the right. Ball-Stud Speed Clips were originally developed as spring catch fasteners on aircraft access doors, inspection panels, sealing strips and other similar assemblies requiring repeated disengagement. The conical shape of the receiver means it can accommodate minor misalignments.

Pull-out tensions, depending on the material thickness of the Speed Clip and the stud used, can be provided from 3.5 pounds to 50-65 pounds. Various panel thicknesses are accommodated by varying the stud lengths. I can mount the receiver on the edge of the interior work surface of the cabinet, as that board will be thick enough to accommodate a receiver, fitted behind a piece of bronze plate or something like that.

Then there's the hardware for the drawer pulls. That remains undecided though there are some leading contenders.

Here's a view of the cabinet with doors closed, the normal arrangement the cabinet will have:


There need to be a couple of pulls mounted on the bifold doors, probably on the inner door of each pair, somewhat close to the hinge line.

As I've worked over the past month or three to obtain shop drawing take offs from the main sketch I've also reconsidered the middle section of the cabinet, and have decided to revise it. Previously, I had fitted a 'step-tansu' arrangement of storage, however I came to see that it wasn't a very good use of the available space inside the cabinet, and that since display is one of the functions of a step-tansu, and storage is the primary function of the cabinet, these things were therefore at cross-purposes.

I decided to take the steps out from the middle and reverted the area to an earlier arrangement of having adjustable shelves inside with a central divider. The central divider makes for a configuration where with one door open there is a dedicated shelf space:


You can also see in the above sketch that the drawer detailing has bene fleshed out and modified a little bit. I'm also going to look at placing a tiny low railing along the front of the middle section, an architectural motif, and see how that looks. A lot of Chinese cabinets have them and they look pretty good to me and serve a useful purpose of keeping things contained within.

I made the top and bottom edges of each drawer front a little bit thicker, which makes the top and bottom through-tenoned connections between drawer front, runner, and drawer side even stronger, and adds a horizontal visual emphasis, makes the dividers more clearly demarcated, to put it one way:



The color of the Shedua drawers, etc., is a little off in these sketches. In reality that material will be a bit browner than it is greenish.

I feel that the changes in the middle move it away from being a storage space of a somewhat particular nature (in terms of what sorts of things could be placed on the steps and inside the irregular compartments), to a much more generally useful arrangement with the shelves. The sideboard could serve equally well as a wardrobe I think - it's versatile.

I have shared these ideas with the client and am waiting to hear back from him to see how he likes the change, or not. If he wants to keep the step tansu inside, I will make that for him of course, but for our cabinet in this pair, we're going with the shelving.

All for now, thanks for visiting.

Saturday, January 16, 2016

An Embarrassment of Riches

The past couple of years in business have been sufficiently solid that I have been able to make investments in my shop infrastructure. Most of that has been by way of large woodworking machines, many of which were purchased used, some from reasonably near to where I live, and some from quite afar, including Germany, England and Japan. My business is important to me so I chose to take any extra capital that came my way and put it into my business, as opposed, say, to a new car, new clothes, heat for the shop....

Those have been big investments for me and I've made note of the new acquisitions as they have come about here on the blog. In terms of the big equipment, my shop is getting pretty close to where I want it, and a very much greater amount closer to what I want than the time I was working out of my kitchen on a sawhorse, which was when this blog first came about.

I feel blessed to have been able to make these investments in equipment, after having made do at times with a lot less, and having to rely upon the good graces of others at times to move projects along by way of equipment I did not have.

Along with the big lumps of iron that I've dragged into my shop, I've also been investing in all sorts of hand tools, most of which have come out of Japan. I don't generally remark too much on those items here, though that does not mean they haven't been incredibly important to me or that I do not treasure them, or that pictures of them haven't appeared in past postings here and there.

It's more I didn't want to make this blog about 'tool acquisition gloats'. I'm generally more interested in talking about the what/how/and why of the things I make and design, and a bit less about tools. I am however very interested in tools, and enjoy having discussions with other woodworkers about tools, so long as were talking about tools from the perspective of using them and not merely collecting them. Tools are the instruments of the craft and how could you be into your craft without similarly being interested in the tools which you wield to accomplish that craft? The funny thing is, I do meet and know quite a few woodworkers who churn out product without seemingly having much interest in their tools or anyone else's tools. That's a bit weird to me, but whatever.

Today a special package arrived from Japan, and I'll break my normal practice and make some mention of them, as I feel very lucky indeed to have them.

It's a set of chisels, 16 in total:


They range in size from 1mm on up to 60mm. All are White paper steel #1 - the blacksmith uses a special lot of white paper steel ingots, purer than usual, from the 1980's if I am not mistaken. Japanese blacksmiths tend to hoard special chunks of material in the same way that woodworkers do.

These chisels are made by Watanabe Kiyoei, who makes chisels, and planes, under the brand name of Kiyohisa. He's based in the heartland of Japanese blacksmithing, Yoita Village, near Tsubame City, Niigata. I've visited that village many years ago, though I met other smiths at that time not Watanabe-san.

I already have several tools make by Kiyohisa, including two planes and a few various chisels. I've found them to be exceptionally beautifully made, easy to set up, easy to sharpen and they hold an edge tenaciously. In my experience, Kiyohisa tools are among the best made, and I mean at any point in history. I'd put only a few makers in the same league.

Now, my experiences with Kiyohisa tools seems to have been widely shared by those who have acquired his tools, and as a result a waiting list has grown and the wait gotten longer to obtain them. I ordered a couple of fishtail chisels for a friend a few years back, and the wait at that time was supposed to be 3 years "or so". Well, the "or so" measure now means that the wait for his tools is likely something like 6 years or longer. I don't know exactly how long it is, but in general it is longer than I would be inclined to wait myself.

The Kiyohisa tools I have acquired in the past few years happened to have already been on dealer shelves or were regular-order items with a dealer and periodically restocked. In one case, I ordered a reverse trowel-neck chisel, or gyaku kote nomi, and after a year had passed from the order date the dealer offered to sell me one he already had in stock but fitted with a new handle to meet my specs. Otherwise I had all but given up on getting more Kiyohisa. Not that there aren't plenty of other fine products from other excellent smiths available, but when you find something you really like, you kinda hope for more of it I guess.

So, I have sitting in front of me a 16-set of Kiyohisa 'Kamon' chisels, and these chisels are totally made for me, to my specifications, specification which included type, sizes, length of head/neck/handle, type of handle, type of ferrule, type of striking ring (kashira). I did not order these 5 years ago, but within the past 12 months. How did this come about?

It was pure happenstance really. A tool dealer mentioned about a year back that a Kiyohisa chisel set had been made for a customer but he had lost contact with the customer and if he were unable to locate the customer the chisels might be available for purchase. He thought I might therefore be interested. I did a bit of digging around and located an email address for the person who I thought was likely the customer, sent that along and lo and behold that turned out to be the connection to the rightful buyer.

While I was only trying to be helpful, the dealer felt obliged to me as a result and on his own impetus asked Kiyohisa if he could possibly fit a special request in to the production schedule. I didn't know that could be even done, so I was unexpectedly faced with a special opportunity. That rare chance has materialized as this set of 16 beauties.

How about a closer look?



These chisels are a special configuration. They are longer than regular bench chisels, oi-ire nomi, and about the same size as mid-size striking chisels, chū-tataki nomi. They have flattened shanks, what are termed hiramachi style, except the proportions of handle, neck, and head are a little different than standard hiramachi chisels. The flattened shanks allow for deeper mortising, beyond full head depth, without risking that the shank will bruise the mortise opening as can happen with rounded shank chisels.

The handles are gumi wood (more on that below) and are longer than standard, since I have larger hands than the average Japanese carpenter. All the chisels have a single hollow on the back, though I had the option for multiple hollows on the larger chisels. I prefer the single hollow actually, and the argument usually advanced for multiple-hollows, that they provide better support when paring or chopping with a portion of the blade on the work, doesn't amount to much if you have a good range of chisel sizes to choose from. The multiple-hollow chisels, as they have more cutting steel on the bottom contact surface, are somewhat harder to sharpen and keep flat than the single hollow kind.

As mentioned above, these are a special type of Kiyohisa chisel, the 'kamon' model, a term which means family crest. The Watanabe crest is three dots over a bar:


The three dots, or mitsu-boshi, refer to three stars, which is a reference to a constellation within Orion, one of the 28 Mansions in Chinese astronomy. In the west these three stars are known as the 'three Kings'. They are in a line, hence the line under the three dots.

Specifically, kamon Kiyohisa refers to special edition chisels and planes which have received a low-temperature tempering. The usual minimum achievable tempering temperature is supposed to be around 160˚C, however Watanabe-san, through some alchemy (likely relating to special steps he takes in preparing the steel and its carbides  -it would be one of his secrets of course) is able to temper at lower temperatures than other smiths. He has produced chisels and planes with tempering temps ranging from 150˚C on down. I have a 150˚C plane and a 135˚ plane from the same maker (the tempering temperature is inscribed on the back of the tool).

These chisels I just received are all 100˚C tempered.

Several shops in Japan that carry Kiyohisa won't sell the Kamon models out of the country, but, well, like I said before, I was lucky. Please don't hate me for being in the right place at the right time.

I feel that I have quite possibly reached the end of the road in terms of chisels I would like to have, or dream of having, and I'm pretty much there as well with hand planes.  I'm looking forward to setting these new chisels up and putting them through their paces.

A few more pics now of these tools:


With a 16-set, I've have been able to add a bunch of chisels in those half sizes that I have sometimes wished I had on hand in the past.

Largest and smallest together:



Some forge weld lines to look at:



These chisels have a delicate feel, and yet are comfortable to hold:


Gumi is my favorite tool handle wood.

The gumi handles are cut out from branches, and thus the pith can be seen:


Gumi has been referred to by some as 'Japanese Boxwood',  however this is totally erroneous. Boxwood, as such, a genus of about 70 species in the family Buxaceae. Chinese boxwood, for example, is buxus sinica.

Gumi comes from the family Elaeagnaceae (try saying that three times fast; the scientific name is Elaeagnus), part of the plant order Rosales. It is a deciduous shrub getting up to 8m tall at most. There are some 50-70 varieties, however the wood used for utensil handles, gumi, associates to E. multiflora specifically.

The English name for Elaeagnus generally is Silverberry, with E. multiflora being termed 'Cherry Silverberry'. The Japanese also call this particular species natsugumi.

A drawing showing parts of this plant:


Here's a photo of the plant when fruiting:


Source: Wikipedia.

By accounts I have read the fruit has a sweet yet astringent taste, apparently a bit similar in flavor to rhubarb.

With 16 chisels to set up and sharpen, it will be a while until I have a chance to use them all, but I'm looking forward to getting to know them one by one, cut by cut.

All for this round - thanks for visiting the Carpentry Way.

Thursday, January 14, 2016

A Ming-Inspired Cabinet (26)

Post 26 in a continuing series, which might be interrupted at any point to dig into other topics, you never know.

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Some reader, in a private communication a bit too sensitive to be shared publicly, has been indicating that I am not dressing sexy enough for these posts, so I thought I'd show y'all a little leg today. Hmm, maybe I'll even go so far as to show a LOT of leg, how about that? Hah!

The first task was to take the leg blanks down in dimension a little bit, not something particularly meriting photography. The next task was to mortise the ends of the legs for the bronze leveler feet. These mortises were 1"x1"x 1.0625" deep, and I wanted to approach the task in two stages, the first being to rough out the mortises, the second to bring them out to dimension. The mortises were to end up square-cornered, so they would be finished by chisel work.

A drill is the standard choice, but drilling into the end of a leg, a task which on the surface might seem easy enough, is in fact a bit tricky most of the time. Unless the leg is short, it won't fit into a smaller size drill press, and if it is long and you have a standing drill press, then you will have to construct some sort of fixture to hold the leg on a line axially true to the drill chuck.

The legs I have could possibly be squeezed into the milling machine in a vertical orientation, however why do that when I can mill at a 90˚ angle, horizontal I mean, with the right angle accessory?:


The right angle accessory, which came with the mill, is a seriously heavy chunk of iron and steel. I use the power z-travel, using the table as a lift to help raise the attachment up into position.

Here, I'm relaxing the tension on a center grub screw which spreads the collar and allowed the attachment to mount more easily - with the grub screw eased off, the attachment will remain in place height-wise on the quill:


At this point the casting of the attachment can still be swiveled around, and I therefore worked to align the accessory to the back jaw of the vise using a transfer punch as a dowel and testing the 'pinch' between jaw and rod with a plastic feeler gauge until I had achieved decent parallelism:


As they say on a certain TV commercial from the 1980's, just a li'l pinch between the cheek and gum will get you where you need to be.

With alignment sorted, the two bolts on the attachment's collar could be tightened to secure it onto the quill.

Next step was to fit a drilling chuck and then working to center the spur of the Forstner to the stick:


Another view of the initial set up:


I made a start with the motor, and promptly realized that the spindle was turning the wrong way on the output end of the attachment. Oops! I went to the back of the mill and flipped the main switch over to reverse motor direction. Then I set a depth stop onto the vise jaw and did a test cut:


The cut was okay, except the drilling chuck allowed the Forstner bit to spin a bit, and the bit had actually come loose. I tried re-tightening it but the same thing happened again.

Not wanting to screw around with that, I removed the drilling chuck altogether and put in a collet chuck instead, which can grab the shank of the bit with the many facets of the collet rather than the three used in the drilling chuck. This solved the problem immediately and I can see why machinists often prefer to use collet chucks instead of standard drilling chucks. I'm going to start using them more often too, and an added bonus is that the collet chuck doesn't stick as far out of the spindle end, so it is inherently stiffer. I'm tired of spinning drills in a chuck and damaging their surface.

With the collet chuck mounted, I took care to recheck everything was coming to the correct point:


The drilling itself was effected using the x-axis power feed for most of the cut, turning the hand wheel by hand the last tenth of an inch or so to the target depth of 0.9":


A while later all 9 legs were rough drilled:


I then made up an MDF fixture which would allow me to rout on the end grain to mill a 1"x1"x1.0625" deep mortise:


The completed mortise:


Checking the fit of the leveler foot as best I could:


I felt like the fit was about right, just a hair snug.

A while later, all the routing was complete:


From there, it was a bunch of chisel work to bring the mortises out to a square:


A first fitting:


It came together well I thought:


Later, all the levelers are fitted to the legs:


Another view:


The levelers are fitted snugly enough so that the parts won't separate simply due to gravity and not so tight they can't be readily pulled apart:


The next step was to mill the combined leg and leveler to dress the all the long faces down a couple of hundredths of an inch:


All four faces on each pair were cleaned up, until I had this tidy pile of parts, of uniform dimension and all square in section:


Making the legs square in section is but a preliminary step - next I'll be making the leg section slightly rhomboidal. Here I've marked out the legs to keep track of which faces get milled at which angle:


All for today my friends. Thanks for visiting! On to post 27