Thursday, March 10, 2016

A Ming-Inspired Cabinet (41)

Plugging away on the bubinga, with the current piece du jour being the vertical divider panel in the central compartment. This board has multiple mortise and tenons top and bottom, joining to the two main horizontal divider assemblies in the cabinet.

I have recently discovered that my Wadkin PP dimension saw, pride of Great Britain and all, assembled by craftsmen in lab coats and all that good stuff, does not cut exactly 90˚ with its adjustable miter fence when the fence is in the '90˚ position by index pin. It cuts a near-perfect 45˚ in the 45˚ index position, however not in 90˚. Since the miter fence is not adjustable in those index pin mechanisms, and therefore depends upon the precision of those detent positions in the table for (some) angle settings, it is likely that at least one of those detent positions is not dead nuts. Added to that issue the face that the face of the miter fence casting is not square to the table surface, but then again, the sliding table casting is bowed too, so hard to know exactly what is what at this point. Grr. Oh well, just another machine to muck around with, which I will do when I have the time. I guess I can learn about scraping soon(?).

For now, I correct the out of square cuts with a plane on the end grain:


There's something vaguely pleasing about end grain shavings:


I didn't take any picture during the joinery cut out, save for a stage near the end where I am rough cutting the spear point miters:


Then a paring jig is used to take the miter closer to the line (but not all the way there quite yet):


Afterward, using a plane to clean up the front edge of the vertical divider board:


It was then time to start fitting up. The first part I am fitting is the upper front cross piece, which is dadoed for the two sliding doors which will be built later on:


On she goes:


A little further down - a view from the backside:


After a few adjustments, the rail could be lowered most of the way:


A view from below however reveals the rail is not fully seated yet, as it is sitting high on the spear point (just as intended at this juncture):


A little more paring of the spear point mortise ensued, followed by a few licks with the plane on the front edge:


The completed joint, as viewed from the front:


The tenons protrude for now, however they will later be trimmed flush with the bottom of the grooves after wedging:


Now for the connection for the upper rear rail, which is a single tenon:


Getting the rail started on its descent:


Fully down, or so it appears:


I think it is very close but maybe a little adjustment required yet to get a tight shoulder abutment:


A view of the same connection from the backside:


Now fitting the lower shelf's front rail, which is twin-tenoned with a spear point:


Getting there - this view is actually of the undersurface of the rail (the parts are oriented upside down):


Mostly down:


The pencil lines you can see indicate the lines to which the mortise will be opened up later to accommodate wedging. At this point the spear point is still a distance from closing.

A while later this connection was completed:


That leaves one more rail to fit on this set, and that will be part of tomorrow's shop action, along with assembly #2, for cabinet #2.

Thanks for visiting the Carpentry Way. Comments always welcome. Up next: post 42

2 comments:

  1. I think some of the problems might be related to the age of those machines. I am probably the XX owner of my tablesaw, and it has probably had its share of dents while being moved from place during its course of life.

    You can still get nice new equipment that will be really accurate, but the price will be a lot higher than what I can afford to pay.

    I hope you'll be able to sort out the problem once you find the time for it.

    The cabinet build itself is looking spectacular.

    Brgds
    Jonas

    ReplyDelete
    Replies
    1. Hi Jonas,

      thanks for your comment. It's true that some of the problems on this machine relate to age and wear and tear. The main pivot, for example, on the miter fence has been repaired with a helicoil at some point in the past, and this may well have contributed to the imprecision of the miter fence detent positions. It's a little odd though that it is dead nuts at 45˚ only though.

      The bowed table could be caused by dings and dents on the upper surface, or it could have been an improperly seasoned casting.

      I like a lot of things about the machine, and I'm glad to have it, but there are definitely aspects to it that don't float my boat so much. The crank handle for the raise/lower, for example, is physically close to the table lip and it is easy to rap your knuckles on the table when spinning the handle. There is a persistent rumble emanating from within when it is running. The rip fence is heavy and not especially easy to move, and the fine adjust knob on the rip fence is so close to the table top that it is hard to turn properly. The fact that the rip fence can tilt seems, well, unnecessary.

      It's curious to me that the miter fence has detents for 90˚, 45˚, and 60˚ - but not 67.5˚ (for octagons). Surely octagons would be the most common polygon to miter, after tetragons (4-sided)?

      I wish the sliding table had outrigger support to longer pieces could be properly carried for cross cutting and mitering.

      The question for me at this point is whether I want to spend the time and money to address the main issue, which is the bowed sliding table and lack of outrigger. I have concluded that the best solution would be to have a brand new table CNC fabricated out of mic-6 tool plate. It's all very doable, at a cost, and it might make more sense to obtain a different machine, which will surely cost a lot more. It's hard to know whether one is throwing good money after bad or not.

      First world problems or what, huh?

      ~C

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