Saturday, January 9, 2010

Battari Shōgi 10

This is the tenth post in a series describing the construction of a battari shōgi, a type of fold-up bench or produce stand which associates to Kyōto-area merchant's houses. I'm constructing this to replace its worn-out predecessor at a Boston Museum. Previous installments in this thread are to be found in the 'Blog Archive' to the right of the page.

Today was fairly productive- not compared, say, to the output of a 6 hour shift at an Ikea factory, but I managed to move a few things along all the same and felt like the day went pretty smoothly.

Today was the day where I got to spend a little time on a friend's metal lathe. I haven't worked on a metal lathe since I was 16 years old, but it's like riding a bike pretty much, if you know what I mean. My friend George has a 1950's-era Monarch lathe, which has some sweet Art Deco styling. It originally came with vacuum tubes inside which gave it's DC motor variable speed. A pretty cool little unit - I want one!! It would look great in our kitchen, LOL.

Before setting off, I cut into the corners of the Lignum Vitae blanks as I was worried the arrises might tear off when the cutter on the lathe bit into the wood - this, I discovered later, may have been unnecessary, but it was entertaining to run the noko into the wood all the same:


I turned the main spindles and they came out well:


The Lignum Vitae is a delight to work on the lathe- it turns cleanly, almost like plastic, even with a only a marginally sharp cutter.

The other task was to turn a section into the floating spindles which are to be used on the main hinges of the bench:


Well, I say floating, however they will be glued on one end to the bench long side rails. Maybe the glue will bond these materials, who knows?- it isn't critical to the success of the connection, that's the main thing.

The main spindles I turned so as to have about 0.008" clearance in their sockets. It's hard to know exactly how much space is really needed, however given the extremely consistent environment in the museum, and the minimal movement likely to be seen in Wenge and Lignum Vitae, I simply wanted a solid connection with minimal rattle. Here's the spindle coming through the leg mortises with their inserts:


A side view:


While I'm at it, how about another view?:


The spindle is a hair longer than the mortise through the leg so as to give the leg a little side to side float, and to allow for seasonal movement.

Here's the fit of the floating spindle stock into one of the bolster mortises:


So, the next task on the list was to mortise the ends of the long side frame rails for the spindles, but a couple of things stood in the way of that objective. While I had the frame apart, I took the opportunity to groove the frame members for the floating panel, using my grooving machine outside on the sawhorse. It was a sunny day but well below freezing, so I bundled up and moved with, uh, alacrity.

Then I used a small trim router and edge guide to push the groove width out to the target, in this case, 0.610". Here's a look at the inside of the frame, at one corner, with the dado complete:


Next task was to trim the ends of the long rails flush with the short side rails. If I had a sliding table saw or chop saw with a sharp blade that would have been nice, however I made do with a jig and my router to trim the excess length (about 1/16"), finishing with a little scraping on that nasty Wenge end grain. The result was fairly clean:


Here's another one:


It might also be apparent in the above pictures that I have chamfered the rails. This was done inside and out, which of course necessitated a Mason's miter on the lower end, since there is no mitered return. I'll try to remember to include a picture of that detail in tomorrow's post.

Then I could turn to the spindle mortising (excuse the lame pun). First I marked out the center for the mortises:


Then I started the hole with a Forstner:


I chose not to drill too far in with the Forstner, since they are really meant for use in a drill press and can wander slightly if worked in a hand-held drill. I could afford no wandering in this case. After the mortise was started, I used my router and a templet bit with top bearing to machine out the rest of the mortise:


The result:


These mortises were then adjusted to a precise depth (target was 1.000") with a final routing pass:


That's the 15-picture limit for today's show. Stay tuned for more tomorrow, and thanks for taking the time to drop by today. Ready for post 11?

3 comments:

  1. One of the things I notice in your photos are how versatile your horses are. I really need to build a set. Everything I have used & still use seems to tall for me now that I'm becoming more involved with Japanese tools and joinery etc. I'm 6' 5" and if I recall correctly my horses are 34". I need to figure out a good height. How tall are yours? Would my knee height be a good starting height to experiment with?

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  2. Hi Dale,

    that's a great question! Sawhorse height is largely a matter of personal preference and dependent upon the application. As a timber framer (at least I seem to remember, hazily, doing some timber framing once!), I prefer sawhorses that are 24" tall. I'm a little under 6' (@180cm) in height, and the 24" height allows me to place a typical beam, say 7" x 9", etc., on the horse and then place a woodworking machine, like a chisel/chain mortiser, drilling guide, beam saw, beam planer, etc, on top without having to lift too high - - and the result is to place the machine height around convenient hand -operating level.

    Also, the lower horses are more stable with heavy things on them, and the 24" height allows me to easily sit askance on the beam for chopping mortises. If I clamp the piece to the horse, I can squat down at one end and saw in comfort. And, if I am working smaller stock, a 24" height isn't too tall that I can easily bring a foot up and hold a stick in place when I saw it.

    Whatever the height that works for you, a pair of sawhorses of the same height is a good idea (that's one of the reasons the treteau I'm building is being made to a 24" height, so it matches the current one). I'm thinking that for your height, you might find a sawhorse in the 26~28" range about right, if you intend to use the horse in the manner I do. Something about 4~6" above your kneecap I guess. It would be simple to temporarily set up some blocks or crates to a given height and try working on it to see how you like it. Some people like taller horses because they want to avoid stooping (perhaps they have back problems).Horses that are too tall make planing a chore in my view.

    If you intend to do, say, a lot of planing, and want to mount a planing beam on the horses, then you would want to take the thickness of that beam into account along with the typical size of material that you usually work to get the ideal working height.

    I hope the above was of some help to you.

    Chris

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  3. Thanks Chris, that is some useful information. My tall saw horses come from my carpentry days, it was easy to stack and cut 2 x's and sheet goods on them. Not to good for woodworking though. I think I'll cut a set down to 26" and see how well they work out for me. Yes, I do plan to use a planing beam on them as well. Good thing you mentioned that, I'll keep it in consideration as I give the 26" set a go for awhile.

    Take Care

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