13 November 2016

The Moxon Vise

Wodoworking projects in China often take much longer than can be anticipated to require. A case in point is a Moxon vise that I have finally brought to completion. I actually started this project two jobs ago when I still could only envision doing woodwork in my Spartan sized apartment. As with so many other devoted followers of Moulariprionia, I had gotten the original impetus from Schwarz' modern interpretation of the Moxon text and sundry weblog postings. I also looked around at different construction methods that had been created since the Schwarz put his imprimatur on the Moxon vise.

Although I looked at some clever models that featured pipe clamps, from the very beginning I knew that I wanted to use wooden threads for two reasons. Any iron surface is always a hazard to sharp edges. Second, The larger threads of wooden screws are inherently faster to use. There was the problem though of not having an ability to cut threads, internal or external, in wood. I've known of this challenge for a very long time. It was the main reason that I bought a Barnes treadle lathe several years back. A problem with using a more common engine lathe is that few of them can cut threads on the low end of the scale, at around 4 threads per inch. I've noticed that Lake Erie appears to have developed specialized machinery for cutting their flawlessly executed wooden vise kits. I hadn't quite perfected my own tooling on the Barnes lathe before I was made homeless but that's another story for another forum.

I had obtained some lengths of roughsawn pine stock that also were put into making low benches for woodworking and seating. Apartment living requires such dual usage. I was anticipating doing much of my handtool work on a beech Ikea slab, once considering that I might rip it lengthwise and double it up for a more massive workbench surface, rendering it thick enough to be used with benchdogs and holdfasts. I wanted something that was easier to clamp down to a bench surface and many designs did and still do require awkwardly supported vertical clamping on the fixed chop.  Attaching the vertical fixed chop to a slightly longer base makes holding this appliance to a bench much simpler to secure. I managed to use this unfinished appliance in the apartment to make a few items by simply clamping the fixed chop to a table and clamping the wood piece with F clamps. Functional but not exactly satisfactory.

While working at Harvey, I was asked to help them analyze and market their latest production lathe model. I thought that it might sell better if it were marketed with auxiliary attachments in order to promote as a home woodshop in one. There are certainly woodworkers who only use a lathe as their principal woodworking machine. I believe that they call themselves turners. I did some research, looking into historical examples and proposed several attachments that could be offered in order to complement the basic lathe: disc sanding jig, horizontal spindle molder, lathe tool sharpening wheels, horizontal drillpress, circular saw table attachment, and even a leadscrew with a thread cutting accessory. Very few of my ideas ever received responses at Harvey. I was fired when a new shop manager was brought in and he's recently moved on to start his own woodshop entertainment center.

Next I dragged my unfinished Moxon vise to Hangzhou when I was hired there to develop an introductory handtool woodworking program. They were slightly more interested in hearing about my ideas for a Moxon vise, at least, initially. I proposed that with the proper thread cutting tools, it would be possible to outfit the woodshop with such devices and to offer a course for students to construct their own. They understood the idea of a Moxon vise because, as I discovered when they suddenly showed me, they had already bought a Moxon vise hardware kit from Benchcrafted. They just hadn't gotten around to building a vise with it. They let me know that they thought the Moxon vise was very expensive. Somewhat disoriented, I countered that by purchasing a German set of taps and dies, we could manufacture as many Moxon vises as we needed and, you know, manufacture and sell such a bench appliance or, even, offer a course for student woodworkers. They repeated that the Moxon vise was too expensive. 10 months later, I returned to Nanjing with the two Moxon vise pieces without having made progress on it.

I came to the conclusion that I would have to buy a set of tap and die myself and bear the full cost. I had already experienced the tool set that is exported from Taiwan and knew of its unpredictable defects. Schwarz has written about disappointment with inadequately hardened blades. I snapped the blade holding croche the first time that I used one. There are various secondhand models on the market, but that's an impractical option in China. The Beall Tool company offers a setup that requires an electric router. I don't want to put myself into a situation requiring one of these ear damaging tailed devices and I find that the threads on their tools are too fine. Subsequently, Saint Roy's suggestion that one can purchase the Beall taps, (a convenient option for those in North America)  and then manufacture one's own box dies was also out of the question. (Season 27, Screwbox for Wooden Threads) I also lack the necessary means for readily obtaining, fashioning, and finally heat treating tool steel.

I hadn't yet learned about China's newly enforced limits on personal overseas purchases and what grief that can cause those who don't purchase through business accounts. My only remaining decision was to decide which size to buy. While I am fairly confident in the quality of Germanmade tools, their prices do cause hesitation without first having tested one. Looking over the progressive sizes of wood thread cutting tools, I determined to buy the largest that I could justifiably afford. My wife refers to these and all others as her tools since I must purchase them using her credit card account and she is decidedly Chinese. The price differential between the 32mm (1 1/4") and the 38mm (1 1/2") sizes was greater than I dared to cross. I felt somewhat confident that anything larger than on 1" (25mm) could also be used in other pending projects such as the Milkman's workbench. I was also more pleased with 4 threads per inch rather than the Beall standard of 5 threads per inch. As an aside, Beall presently only offers tooling for dowels no larger than 1 1/2".  Getting locked into their system has a clear upper limit; whereas, the Dieter Schmidt offerings ranging as large as 62mm (2 1/2"). Well, I can dream.

In order to avoid marital strife, I did as much as possible to keep my total purchase from Dieter Schmidt as low as possible. I therefore did not buy the corresponding drill bits in the same order, believing that I could easily source the 26mm TDS and the 32mm bit for the major diameter. I also had an adjustable square taper auger bit that could create whatever hole I needed it for, at least, in the short term.
Returning to the theme of how much longer tasks in China require, I've not yet been able to buy the drill bits that I had anticipated buying. I wanted to buy bits that I would use with a brace. I have the necessary adapters, the most common of which accepts the standard 1/4" drive (6.35mm). There is another adapter that allows for a 9mm hex drive. This technology is essentially from the Japanese market and some high quality Japanese woodworking tools do show up in China, occasionally and intermittently, it seems. I've written before about the high quality of Japanese hex drive auger bits but it seems that there is not yet sufficient local demand to import them in the larger sizes or for them to appear on the local market from local manufacturers.
I can find 26mm bits with 1/4" hex drives but anything larger requires an expansive drill chuck at the 32mm size. In the short term, I reluctantly bought a set of Irwin auger bits but upon close inspection, I expect to be disappointed with these. The lead screw is damaged from sharpening the spurs. These examples might have been rejected as exportable (which explains how I was able to buy them locally) or else this sloppy grinding is of the standard level of production quality. Irwin saves on production costs by not polishing the interior of the flutes. Painting drill bits, in this case with a very thick blue coating, is an indicator of low quality manufacturing. Lastly, the length of these flutes is only 1 3/4" (45mm). These are likely to be targeted to the tradesmen who don't drill through anything more than a 2x4. Such truncated flutes cannot expect to deliver consistent results and so, at least, until I discover better made drill bits, the 25mm drill bit might ably produce the 26mm TDS that I need.
coarsely and crudely ground

Readily available bits suitable for braces

A feature that I want to highlight and which I have so far not seen in other models is that I only put internal threads on a block of beech that I attach to the back of the immovable chop. I do this for a few reasons. First, it conserves materials. Beech or whatever hardwood that one chooses for the threaded sections is generally more expensive or harder to obtain than pine or other wood for the bulk of the vise. There is no necessity to making the chops of beech. The thickness of the beech block is ideally enough to allow for 3-4 threads of engagement. Having these as separate elements also helps with long term maintenance. I originally thought that the threads might wear out first, but I am now inclined to believe that the chops will suffer more errant tool damage before the threads wear out. This will allow a user to fabricate a new set of chops and transfer the threaded sections to the new Moxon vise.
Removable threaded beech block

Lower movable chop
Quite a few Moxon vises feature a chamfer on the top edge of the moveable chop, often with an elaborately detailed lamb's tongue, to accommodate the steep angle necessary for sawing the pin board of halfblind dovetail joints.  I've obviated this by making the moveable chop narrower, setting it below the top edge by about half the thickness of the chop. I don't expect a bench appliance to remain pristine so it makes little sense to build it to look so damned pretty.
Cutting the internal threads is the easier of the two operations. The tap drill size (TDS) is, in the case, 26mm. Drilling the hole as squarely as possible will go far in making this vise easier to open and close. The tap requires a standard tap handle to accommodate its 13mm square end. Putting threads on the rod requires considerably more work and care.
I did a test run at making a dowel section after first ripping octagons on a tablesaw. These facets would form the handle section. I made a quick gauge to help me size the rod at 32mm along its length. Ideally one can make this gauge using a 32mm drill bit that will also serve to drill the holes through both chops.  
Gauging the major diameter
It is advised that the dowels be soaked in oil before cutting the threads and I can attest to this method. This does seem to cause the wood fibers to swell. The lesson that I have learned is that the dowel is better off being undersized, which leaves the threads slightly flat and much easier to cut.
One realization that I have learned is that cutting beech with a small V-cutter (larger sizes have two cutters) produces a large amount of heat and the aluminum cutterhead acts as a heatsink.  This operation requires patience but it can also warm your hands.
Using the Moxon while cutting the threads
The one drawback that bears mentioning is that the cutterhead has a lead section that is approximately 1 1/2" (40mm) which leaves some of the dowel without threads. It's hardly a problem on this project but it might require additional planning in other situations.
Unthreadable segment

Schwarz, in his estimable wisdom, has come around to using the same Germanmade tap and die sets.