25 August 2015

Dutch Toolchest: upper and lower sections

Following the lead of Christopher Schwarz and riding the wave that he induced, I built the Dutch toolchest in the early months of 2015 and by springtime, I was aware of a problem with the drop front. It had expanded beyond the allotted opening, making it nearly impossible to remove it, reinsert it, or use the sliding batten to lock it into place. The drop front required replaning about three times over the course of the following 6 months to make it workable. The drop front of the top section is made of white pine by eye.
I wanted to follow Schwarz' idea of a Dutch toolchest lower section on casters. The casters would give me a bit more flexibility in my new work environment and the lower section would house some of the additional tools I had acquired. I therefore rejected Schwarz's construction detail of a sliding batten that required lifting the top section completely off to remove the batten and thereby gain access to the lower section. He uses the lower section only for storing and transporting materials to offsite locations. I was instead drawn to the variation that he highlighted in a posting referred to as the Canadian Gravity Latch. This would allow me the same degree of access to both sections and to show off my Western woodworking skills!
I roughly followed his dimensions and made up the construction details of the gravity latch as I went along.
I have access to fairly clear Southern Yellow Pine so I chose that for my stock. I cannot yet get anything wider than 2"x10" in either SYP or SPF. I got around this hurdle with the upper section by using German made laminated pine shelving boards for the sides. I laminated SYP stock to create the 11-1/4" boards for the main carcase. These were dovetailed with rabbets on the tail boards to lend rigidity and ease the marking of the pins.
Dovetail joint

There was some twist that has started to develop but I managed to squeeze the four boards together, the dovetail joints pulling the corners in square. The back of the upper section had simple shiplap rabbets; whereas, on the bottom section, I had the wherewithal to make a tongue and groove joint. I used some scrap European Beech for the battens. (There is always a lot of this as scrap in this woodshop.) The gravity latch went together without much trouble as I had already understood the principle from having made the upper section.
Thumbcatch on the gravity latch
I unified the two pieces with the same beading plane and a coat of milk paint covered in BLO.
The DTC: upper and lower sections
And it worked for a while without a glitch. Yet since this is China, nothing is ever so easy. About a month or so after everything was together, I started to have trouble with the drop front. It was apparent that the newly exposed surfaces that had been planed down to 3/4"were cupping noticeably.
Newly ajar and uncloseable

Here is a similar example that occurred much faster when I attempted to dimension a piece for a shaving bench.
Released tension after exposing fresh surfaces

My first solution was to cut a series of relief cuts on the inside surface. This seemed viable and I had a circularsaw to execute this idea. After removing the battens, which had evidently done very little to counteract the released stressed with the SYP, I ran a series of sawcuts as deeply as I dared while avoiding the screw holes.
Seemingly reflattened yet still curved

Ribbed for everybody's pleasure

And then I reassembled the mechanism and crossed my fingers. I could see very little effect from attaching the battens and if there was any change to the curvature, it wasn't enough to bring it back to functionality. I pondered adding more sawcuts but I think I had maxxed out on that solution. It then dawned on me that I could simply removed the wood that was interfering with the fit. The battens proved to be prefectly positioned, built-in guides for this operation. I ran a making knife along both battens and after creating knifewall, then I sawed down a bit. I pared out most of the waste before cleaning up and doing the final fettling with shoulder and block planes.
Rabbeted with ease

The result hardly shows the major surgery that has been inflicted upon it. There remains some shelving or interior attachments to be added to accommodate whatever tools I decide to secure in it.

19 August 2015

Duelling Dowel Plates

Every woodworker is ably assisted with access to a machineshop, one with a vertical milling machine, surface grinder, engine lathe, forge, and all the usual tooling. With such a setup, somebody can make a dowel plate with as many increments as available drill bits. For those of us lacking such a tooling bonanza, Lie-Nielsen makes an offtheshelf model that is well worth its price. Actually they make two models, one with factional inches and another graduated in millimeters. A woodworker who wants to make full use of scrap pieces for making straightgrained dowels will do well to make use of  these two tools in tandem.
Only one size is based on the other
It's not widely known that the inch used in the USA was long ago defined according to the metric system as 2.52 cm. [Other inches are also defined according to the metric system.] Not approximately but exactly 2.52 cm, or 25.2 mm (since 1959, in fact). For those of raised on this preFrench revolutionary system, a good number to keep in one's head is that 25 (.2) millimeters equal and inch. This allows us to redefine the two seemingly incompatible dowel plates in a way that allows us to use them together.
Here is a handy list of the equivalence in millimeters for the fractional inch dowel plate sizes.
1/8" = 3.15 mm
3/16"= 4.725 mm
1/4" = 6.3 mm
5/16"= 7.755 mm
3/8"= 9.45 mm
1/2"= 12.6 mm
5/8"= 17.75

The dowel plate holes on the metric plate are: 3, 4, 6, 8, 10, 12, 16

There is no secret code that can be revealed from staring at these numbers but I suspect that anybody who has already used dowel plates will readily see the expanded uses from having both. First, it's practical to reduce the diameter of dowels incrementally in order to produce straight and true lengths. The closer that one can space these steps, the better. As one can see, driving a dowel that just passed through a 5/8" hole into a 1/2" is a whole 1/8" reduction. A 16 mm step between these two can ease the dowel down to size a bit more gradually. The whole sequence of steps for reducing dowel diameters is thus:
5/8", 16 mm, 1/2", 12mm, 10 mm, 3/8", 8 mm, 5/16", 6 mm, 1/4", 3/16", 4 mm, 1/8", and lastly, 3 mm.
Secondly, sometimes, a slightly oversized dowel is what one needs whether to allow for wood compression, in dry or green woods, or due to unreliably accurate drilling setups. This seems to be more often the situation with hardwoods being driven into soft(er)woods. If one is working in fractional inches, an 8 mm dowel is slightly larger than a 5/16" hole (7.875 mm). The same is true for a 16 mm dowel in a 5/8" hole (15.75 mm). With the addition of some metric drill sizes, this feature can be expanded with the fractionally sized dowels being driven into metrically sized holes, too.

I don't know what's easily available in other markets, but I can readily find Japanese manufactured auger bits that use 1/4" drive shafts. This shank size seems to have become a standard for interchangeable tooling in the international market. The Japanese refer to this as a 6.35 mm hex drive. There is also a 9 mm hex drive for larger sized tooling.
A set of Japanese drill bits and a German make

These hex shafts can be used in both three jaw chucks for electric drills or in this amazing adapter that can be mounted into a two jaw brace. There are also adapters that accept 5/16" hex shafts and 9mm hex drill bits. Dieter Schmid Fine Tools, for one, in Germany offers a wide selection of Japanese auger bits as well as the necessary 2 jaw chuck adapters.
Packaged set of three bits for hang hole displays

I don't understand the Japanese sizing system. The packages of drill bits conform to what their customers want so it remains a mystery to me why drill bits might be bundled in a package with diameters: 6,8,9,10, and 12 mm. A bigger mystery is why Lie-Nielsen offers a metric dowel plate. Is it a sign that the Maine brand has reached inroads on international markets where the inch is merely a curiosity? Regardless of their reasons, I hope that this posting makes clear why both these plates ought to be in every woodworker's kit.

14 August 2015

First Course in Hangzhou

Between July 27th and August 7th, with the help of my assistant, I instructed my first Chinese students in woodworking, focusing on developing skills and joinery with handtools. A class of budding galoots spent their first week on smaller projects in order to devote the second to a Japanese tool chest based upon the initial design of Toshio Odate.

Something here that doesn't look right
 I was impressed by the level of energy and commitment among a group of true beginners. Their communication skills helped enable my lesson plans immensely.
All on task

Adding an ear to accept a grommet

Fitting the rebated bottom boards

Anarchy with filgree
Paring out a shoulder for a rabbet plane

These future heartbreakers could not be present for the group photo on the last day because their mother told them that they must be home before the streetlights came on

Fettling for a final fit

A pride of students and their accomplishments
The next scheduled course offering will take place during the first week of October.

13 August 2015

Starrett Combination Square Rehab and Praise

I've been annoyed with a problem that I suspect is common with similar vintage tools ever since I acquired a secondhand 12" Starrett combination square. While mostly a feature of its metalworking past, the scribe had trouble staying in its hole, dropping out unless it was inserted just so with the last bit of holding power left in the head.
About the same time that I was struggling to find a similar tool for students, I perused the Starrett website and noticed that there was an option for contacting the company. I selected "parts breakdown" in the reason scrolldown box. I wrote thus:
"I have an older model combination square with a scribe that has loosened over the years. Can you suggest any methods to adjust the hole that it inserts into or other ways to keep it secure and still useful?"
An acknowledgement arrived immediately and a fuller response forthwith. I reprint the email:

The Starrett part number is 01087-1/2. 

This awl bushing is just a small brass sleeve that has a taper on one end. The taper actually is what holds the awl in place. My guess is the taper section finally spread out over the years and the awl is now loose in the holder area. The old brass sleeve will need to be drilled out and the new sleeve inserted in its place (press fit). 

We can send you the replacement sleeve at no cost….the problem is getting it to you in a cost effective manner. If you have a suggestion on how best to send this low cost part to you – please advise.

Looking forward to hearing from you in this matter.

Ken Duffy

The L S Starrett Company - Export Department
121 Crescent Street
Athol, MA 01331   USA
Email: kduffy@starrett.com

Saints praise Mr. Duffy! Not even a demand for a receipt or a photo of the problem. I merely had to give a physical mailing address and the replacement parts would be on their way. Oh, I even asked for a few extra in case I screwed up the installation. He sent me five replacement parts. For those who don't understand why Starrett tools cost so much, this level of service explains their relatively low cost for the value of a tool that will outlive its owners.

The little parts arrived by FedEx directly from Athol, Massachusetts. I had offered to buy the free parts for the cost of shipping, but I was charged nothing. Not a cent or a fen. 

The instructions were to drill out the old shim and then reinsert its replacement. Being lazy and wary of letting my 'hard to replace in China' square come up against a twist bit, I pondered an alternative method. I took a short drywall and turned it into the soft brass insert. I then squeezed the head of the screw between vise jaws. 
The crudest solutions are sometimes the most elegant
I held a block of hard wood against the head and smacked it with a big ash mallet. It was driven out easily. Hurray!
I could see more clearly what had happened over the years.
The curtain peeled away
There are three flaps of metal on the end of the brass shim stock that compress against scribe. Either due to metal fatigue of abrasion, they no longer provided enough friction to hold securely. It's conceivable that after withdrawing the old sleeve, I could have pinched the flaps closer together and reinserted the original one. The amateur conservator in me was tempted to do so. The outer edge of the brass had been subjected to a lifetime or more of getting stabbed by the scribe's tip.

Shiny and shinier
I kept the original but decided to use the new sleeve and promised myself to cease being so rectally retentive. After blowing out the void in the head with compressed air, I pushed the new sleeve in with just finger pressure and then pressed the head against a flat surface to bring it flush.  

The tool rejuvenated and ready for the next lifetime of careful use.

From China I securely sing your mechanical praises, Laroy Sunderland Starrett, born in China, Maine!