Monday, January 5, 2015

Gateway (26)

Post 26 in an ongoing series describing the design and construction of a kabukimon, a type of Japanese gate. Post 1 in this series can be found here if you'd like to start at the beginning. Each post links to the next at the bottom of the page. Recent installments also located in the 'Blog archive' index to the right of the page.

--------

Started out today with making the end cuts on the 11.25"x13.75" main posts - two cuts with the Makita and the end is trimmed, the goal being to have the two cuts be very closely in plane so minimal clean up is required afterward. Let's have a look-see then.

First cross cut done on the right side post:


 And number 2, same post:


A check on the post top, but most if not all of it will be under the large copper cap to be fitted later. I'll probably epoxy the crack closed though.

Some clean up with a hand plane is in order - then, when I was done I realized that as this was the top of the post, and to be covered with the copper cap, the planing was, uh, unnecessary:


Oh well, it was good exercise at least. Note that you can see a touch of sapwood at the bottom left corner of the end grain shown in the pic. I had asked at the mill for the timbers to be free of sapwood, however they did not bat 100% in that regard. The sapwood portion does not, however, run the length of the stick.

Another post, another pair of cuts:


You can see by the end grain that this post came from a bigger log than did its partner.

This is the bottom surface of the post, so the surface needs to be flat and square:


Last one on post two came out fine also:


This is the top of the stick, so the surface flatness is less critical, though I still cleaned it up afterwards with a hand plane.

Next up were the mortises in the beam for the stub tenons associated to the kabuki and magusa:


Another view:


The above pic shows the orientation of the mortise as it will be in the field. The stub tenons are at the base of the kabuki. As you can see, the stub tenon mortises are asymmetrical on this side of the post. There's a reason for that.

The other little mortise you see is for the magusa, which is a door header fitted directly below the kabuki (the main crossbeam):


While cleaning up the mortises I had a sweet little end grain pare happen:


It's a keeper.

(not really)

The other post through the same stage:


Still a little clean out to do in the main mortise, however I'll wait to do that just prior to trial fitting. Most of the waste has been trimmed out.

Trimming the slot mortises continued on the kabuki:


And at the end of the day I made a start on the nose piece tenons, which are fairly long suckers:


Looks like a giant pair of silicone ear plugs at this stage. That's it, I'm getting into sculpture now.

(probably not)

All for today - thanks for dropping by the Carpentry Way. How about sidling over to post 27?

8 comments:

  1. I think planing endgrain with a sharp plane is one of Life's great pleasures. There is also the possibility that I need to get out more. The pieces are looking great so far.

    ReplyDelete
    Replies
    1. Paul,

      there is something nice about taking shavings off of end grain. It would be nice if I could stand the beam on end and work on it in the normal planing position however!

      Thanks for your comment.

      ~C

      Delete
  2. Umm Chris... I know you're busy and all, but it looks like your legs are gettin a lil chunky on that chisel! Beta-ura?
    Ahh it's the season, happens to the best of us ;-)
    Owen

    ReplyDelete
    Replies
    1. Owen,

      I guess it is on the way there towards leg fatness, but since I never tap out a chisel, that's pretty much the direction things will take. Teasing accepted.

      ~C

      Delete
  3. Hey that was more productive than I'd expected! I often wondered about chisels as once I read your article I started seeing beta-ura everywhere - but not many people use japanese planes where I am, though chisels are fairly common. Why not tap out chisels? Is it just accepted that since it's a smaller area the benefits are negotiable? This brings another question actually, do you ever hollow grind your chisels? I've assumed that people don't with japanese blades, because I can't get my hollow ground bevels to vacuum to the stone and I would like to blame that on something (I only ever see it with kanna blades) ... I'm curious because if you did, eventually your "landing" would disappear and you'd need to tap it out, (I believe). If you don't hollow grind, does the landing remain a consistent size over time as you flatten, increasing it at a fairly similar rate as sharpening would reduce? Last question - is hollow grinding unnecessary because the majority of steel you're sharpening is softer?
    Thanks as usual for sharing your knowledge, this gate looks like quite the fun project! I imagine it's quite the transition going from the tables to this - probably didn't get to use that mortiser on the tables did you :-P
    Cheers,
    Owen

    ReplyDelete
    Replies
    1. Owen,

      you've been saving up your questions for a while I see.

      There are a couple of reasons to support tapping out chisels:

      - to maintain the aesthetic of a nicely shaped ura
      - especially with larger chisels, to reduce the amount of steel that must be dressed flat
      - if the chisel were severely chipped on the edge

      I have learned not to drop my chisels, and will sacrifice a limb to stop them from hitting the ground. I am not overly concerned about the appearance of the ura, though that may change now that you have publicly shamed me. I'm feeling most self-conscious about it now.

      I get to tease you back - remember who started this?

      About the benefits being 'negotiable' : I'm not sure how one would negotiate with either the sharpening stone or the tool - perhaps you mean with oneself? I prefer to keep such conversations to a minimum, especially if other people are about. Perhaps you meant to say 'negligible', in which case, yes, the benefits of tapping out chisels for the most part are negligible or at least only worth doing in certain circumstances.

      Hollow grinding the bevel is a no-no with Japanese chisels and planes. You allude to some of the reasons above, however please be clear that the majority of the material being worked on the bevel is iron, not steel. They're not the same thing, and seem to be very often confused or conflated. Look at any Japanese Woodworker catalog and you'll find examples.

      So, here's the thing with hollow grinding. Probably 80% of of the material you are working on the bevel surface is iron, which is comparatively soft. Let's say you move the bevel across a grinder and hog out a concave surface on the bevel. The idea with this technique is somewhat similar to having an ura -- reducing the amount of material which must be worked to obtain a flat plane on the surface. This works fine if the entire material is the same consistency, however after grinding the hollow on a laminated tool, you would then be working a material with a hard consistency on one end (the hagane, or cutting steel) and a soft consistency on the other. The inevitable outcome is that the soft iron is worked down much faster than the cutting steel, and what results is a slackened bevel angle, and a tool that probably won't be holding its edge very long, though it might cut like the devil on those first few passes. A lot of beginners with Japanese tools tend to have the problem of over-working the iron portion of the bevel, progressively making their chisels or planes with more and more acute bevel angles. They will be sharp after the process, but the edge durability is gradually made worse and worse. I've seen this more than a few times. Hollow grinding is like a fast-track route for the same outcome.

      To me, the 'shortcut' of hollow grinding doesn't make any sense, at least with Japanese tools. Working the bevel is nowhere near as onerous a task as working the ura side, and the Japanese chisel/plane blade already has a hollow there to facilitate the process. If you want a difficult flattening task, try working the back of a 2" western chisel- there's a reason many people only work the last 1/2" or so, and things like the 'ruler trick' have become popular.

      ~C

      Delete
  4. Haha you got me there! I did mean negligible - the little box on my phone makes it hard to proofread longer comments :-P It's not so much that I save up the questions, just asking one leads me to another! I could probably stand to do a little of my own research first but people like you make it pretty tempting to "cheat!" That makes a lot of sense though, and I'm sure I would have overlooked that as well - I feel quite fortunate not to own any yet myself, or I'd probably be re-grinding them right now. I also was definitely forgetting that the soft portion is iron. I will be passing this info along to a couple friends, and I'm sure it will be appreciated.
    Thanks again!
    Owen

    ReplyDelete
    Replies
    1. Owen,

      appreciate your comments and questions. Anytime.

      ~C

      Delete

All comments are moderated:

Anonymous comments will be deleted

Spam will be deleted

Comments containing links unrelated to blog content will be deleted