Wednesday, February 3, 2016

A Ming-Inspired Cabinet (30)

Post 30 in a continuing series...

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While the posts connect to the long side inverted 'T' beams by way of a tiny 5mm square peg, the beams themselves connect through to the above-mounted cornice assembly directly, using hammer-headed draw bars. I had previously mortised for these drawbars and their associated fixing pins only on the short side inverted 'T' beams, however I realized it would be better to double those connections up at each corner-  thus the long side inverted 'T' beams needed to be mortised for both draw bar and fixing pin:


You can just see in the above photo that the fixing pin mortise has been filled with a sacrificial piece to preclude blowout when mortising cross-wise for the draw bar.

The sacrificial pins were tapped out afterwards using a metal drift pin:


Setting the inverted 'T' beams aside, at last I can deal with the stretchers. I decided it would be prudent to make up some pieces to gauge the spacing for the stretchers, since, after so many cut out steps, it was likely that there would not be perfect fidelity to the layout established in the drawings.

Here, the legs have been clamped down tight and the test pieces fitted:


 As it turns out, the lengths were very close to the target numbers, as were the bevels, save for one corner which was slightly out for some reason.

As the posts slope both ways, none of the cut lines on the stretcher shoulders are 90˚. With the bevel on the broad face of the stretcher the angle is all too apparent, however on the narrower edge of the same stick the cut angle is only at hair off of 90˚, at all of 89. 85˚ or so:


This splay-posted structure is one of the more complicated ones I have done, simply due to the fact that the splay is so slight that many of the angles are just very slightly off of what they would be if the posts did not slope at all.

Another view:


The following picture shows well, I think, that even though the angle of 89.85/0.15˚ is a very slight slope, it counts for something. The bevel gauge is flipped around to show double the effective angle, relative to the fence:


Now working on the tenon cuts on the long stretchers:


To cut each tenon, 4 separate set ups are required:


This one is about halfway along:


The larger bandsaw was used to rip the tenon waste:


After roughing out, the tenons on the long pieces looked like this:


Then on to the router table to clean up the surfaces and bring them to dimension. The cuts off the bandsaw are fairly close to the line, so the amount of router work is minimal, which is the way router bits cut the best:


After routing:


Then, working again on the short stretchers, a second check to see that I am in the ballpark for length, shoulder to shoulder:


The tenons are then further cleaned up, and slight adjustments made, using various chisels:


 This tenon is complete:


After the tenons are done, then they must be fitted to their mortises, which seems to take a while. Here, first short side stretcher is fitted up:


A closer look at one shoulder:


And the other:


Maybe a closer look wouldn't hurt:


On the exit face:


A while later, the second short stretcher was fitted:


Then it was time to work on the long stretchers again - here, I'm checking the shoulder-to-shoulder lengths before final clean up:


A bit of a staged photo for sure, making use of the fact that the parts can hang in place simply by friction on their side shoulders.

I cleaned up the tenons on those two long stretchers, and that is as far as I got today. The remainder of the stretchers could be fitted up tomorrow, however perhaps my optimism is premature in that regard. They'll be done when they're done.

Thanks so much for dropping by and checking out the comings and goings here. I hope you'll return for the next installment. On to post 31

9 comments:

  1. Hi Chris,
    beautifull and interesting as usual! just a question, now that you have that wonderfull piece of german cast steel that works magic in any direction, why do you still choose to use the router table?
    François

    ReplyDelete
    Replies
    1. Hi François,

      appreciate the comment and thanks for the question.

      While I do sometimes toy with the idea of getting rid of the router table and only using the shaper, in the interest of freeing up floor space, there are a few strong reasons why I am still making frequent use of the router table in my shop:

      1) Currently the shaper is set up to run the molding profiles on the cornice pieces, and thus I have no wish to disturb it. It is an advantage to have the router table for such times - indeed, many shops which do a significant amount of shaper work tend to have more than one shaper, as it allows them to keep one machine set up for a certain frequently-tackled job, and use the others for other task, dedicated or flexible. It is the set up, after all, that takes 90% of the time.

      2) The router bit I am using to trim the tenons is small, having 1/4" shank and has a cutter measuring 1/2" ∅ and 1/4" depth of cut. Until recently, I did not have a collet at 1/4" ∅ for the shaper, so that's one thing. For another, the small bits like that work better spun at higher rpm, and the fastest the shaper goes is 9,000 or so, unlike the router table which goes up to 24,000 rpm.

      3) I have a fairly extensive selection of tooling for the router table, but currently very little for the shaper.

      4) configuring the shaper for a task generally takes a fair bit longer than the router table, so if it is a small run of parts, I might generally be more inclined to do the work on the router table.

      I think I'll continue to find the router table a worthwhile tool to have in my shop, even once I have a more complete set of tooling for the shaper. It seems to me that the smaller router table is still going to be the go-to choice for small cutters, high rpms, and unique or small runs of smaller size, shorter length parts. The shaper will excel at moving large cutters with great power, and has a stock feeder, so it will be the choice for larger sticks, larger runs of longer length parts, molding work, millwork, and large tenoning operations. For woods prone to burning from a cutter, like Black Cherry, the shaper will likely always be a better choice if it can be used for a task.

      There certainly are a good number of 'medium tasks' with medium sized pieces of wood, which could be tackled equally well with shaper or router table.

      ~C

      Delete
  2. Thanks Chris for your quick answer, that makes sense. I can remember when I was younger, that was before the CNC centers that can spit window components in 7 minutes, craft shop with 6 or 7 shapers ligned in the shop, each one set for a single operation.

    François

    ReplyDelete
    Replies
    1. Yes, and I might add that near here a CNC job shop just added their second large 5-axis machine, to the 4 or 5 other CNC routing machines they already have. You could fit a car inside the new machine.

      Seems like the CNC shop wants to have as many CNC machines in their facility as those craft shops you mentioned had/have with their 6 or 7 shapers.

      ~C

      Delete
  3. Chris, It's coming along beautifully. Especially exciting to watch the progress at this point.

    ReplyDelete
    Replies
    1. Thanks Brian.

      By the way, I congratulate you on your new blog,

      https://brianholcombewoodworkerblog.wordpress.com

      I checked it out and looks great! Keep up the excellent hand tool work.

      ~C

      Delete
  4. Yes and less wages to pay, replace 6 shaper operators by 1 CNC operator just feeding the machine!

    ReplyDelete
    Replies
    1. I believe that more than few people seem to have picked up on your idea in recent years.

      Delete

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