Wednesday, July 22, 2015

Japanese saw vice: finished and explained

It took me a while, mostly I didn't want to cut in half the rauli glue up since it looked like it wanted to be a table (despite the horrible grain orientation I made).

But yesterday night I cut everything to size and spent a good deal of time shaping the vice with a kanna. There are several points that became clear to me during the making and think they are worth noticing.

As we saw already, the 240mm size comes from the height at which the file stands when you are sitting.

The first section on the left of the drawing is 30mm. Then comes a gap of 90mm followed by another 30mm section that's slightly rounded. The holes come here. Then 90mm more and you reach the bottom. This last section is composed of two different surfaces: the one receiving the wedge and another one that is free. The wedge is made by making a line at 45mm of the bottom and half your thickness and taking that out with the plane. Once that's done, you need to reduce the part between the end of the wedge line and the holes so the only point of contact is where the holes are. This make for a nice clamping pressure.

I hope you see that where in the lines of the holes I didn't plane. So this is the gap you are looking for

The process of making is quite straightforward. Start with a large piece of glued up wood and cut to the lines with your azebiki:

Then cross cut with your biggest badassest sawest 

Applying some force to my new chumasaru pattern 360mm monster created this pattern. Eats rauli like crazy, almost like a circular saw. That's almos 10mm per pass, and reasonably straight so I could shoot it in a few passes. 

And then use the kanna to define the planes I talked about at the begging.

There I was making the wedge section, working both ways to go with the grain. 

That was yesterday. Today I chamfered the corners and sanded the curvature on top. It goes against my religion to sand but I want the metal fillings to stay away from the wood and near my tray, so I may also put some shellac on it. We will see. 

You need chamfers at either end of the jaws so you can put the saw easily with the jaws closed.

And this is how it looks after first sanding with 280, I put water to raise the grain and now I'm going for it again.

What else? The way I choose the grain orientation was really idiotic. You want to plane against the grain to make the shape, so ideally you have grain goin towards the centre of the vice so you can use the 鉋 from either side. 

I bought 5mm to large bolts, so I'm getting new. You also want it unmountable to plane the surface of the jaws the need may arise. 

Final thoughts in the design. Why the gentle curve on the vice outer face? To reduce weight. If you are gonna move that shit for 35 years of your life up and down, one side then the other, you want it the lightest possible. Why the wedge is so long? Because you can shape it to create a particular pattern of pressure, say press more on the left than in the right. This will help you to deal with wood movement (or at least I believe so). 

Now, just make the wedge, finish sanding and find my little shield. Then off to sharpening. Happy sawing, as Gabe says. 

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